Ep. 220 From the ground up: How to create and care for raised bed gardens | #GoodGrowing
Welcome to the Good Growing Podcast. I am Chris Enroth, horticulture educator with University of Illinois Extension coming at you from Macomb, Illinois, and we have got a great show for you today, raised bed gardening. I think I've answered this question many times in my career. I've built a couple of them myself, and so we are going to share with you today some of the tips, tricks, maintenance, hacks of raised bed gardening. I hate all those buzzwords I just said.
Chris Enroth:Ken is editing this week. He'll know what to do. Just leave it in, I guess. So I'm spoiling this all. You know I don't do this by myself every every single week because I am joined every single week by horticulture educator Ken Johnson in Jacksonville.
Chris Enroth:Hi, Ken.
Ken Johnson:Hello, Chris. Definitely, got to leave that in so we get the the algorithms in our favor.
Chris Enroth:I know. I know. You're yep. And I don't want we're not doing another take. We had to do a retake last week, and you know what?
Chris Enroth:We're just going with it this week. It's you and me. So here we are talking raised beds today. But how are you doing, Ken?
Ken Johnson:I'm I'm doing well. How about you?
Chris Enroth:I am doing great. Now tomatoes are ripening now that it is no longer 80 some degrees at night. The humidity let up for a bit, but not that much. It's humid again. It's getting hot again.
Chris Enroth:Are you getting some some ripe love apples in your garden?
Ken Johnson:We've gotten a few. At our Lukman Garden, we had a bunch on Thursday. They're pretty close. So we got pretty decent amount of rain on Sunday, and I'm a little afraid to go out and look because I have a feeling we're gonna have a lot of cracked Mhmm. Tomatoes that I'm just gonna be tossing into the compost.
Ken Johnson:But Yeah. We'll see.
Chris Enroth:Yes. I I have the same feeling. Lots of cracked tomatoes. The fungal disease, which we have not really had issues with these last few years, you know, where the tomatoes just start dying from the bottom up, It's definitely here this year. So lots of tomato dip, you know, the standard plethora of diseases that they can get.
Chris Enroth:It's it's definitely happening. So, hey, it's August. It's great.
Ken Johnson:Yes. Eventually. So this is usually about the time where, like, yeah, I'm not really care what the guard happens in the garden because I'm kinda over it. But
Chris Enroth:Mhmm.
Ken Johnson:Once it cools off, it'll be invigorated again. But
Chris Enroth:I'm ready for fall.
Ken Johnson:Right in the dog days now.
Chris Enroth:That's that's true. Yes. So, like, when it comes to gardening and even landscaping too, I I know you have raised beds. I grow in raised beds for, you know, certain things. Most of the raised beds I grow in are for work, actually.
Chris Enroth:But so that is the topic of today, Ken, raised bed gardening. We're going to try to go through everything from, you know, why we do it all the way from construction, tips, tricks, materials, what we grow in them, all that. So but I think we gotta kick us off with this this weekend of why raised beds? Because it's a lot of work. Why do we why would we go through all this effort to build a raised bed to grow our vegetables?
Ken Johnson:Yeah. There's there's several advantages, and there's disadvantages too, which we can talk about a little bit. But with raised beds, you know, you're lifting that that garden, off the ground in a lot of cases or higher up off the ground. You know, really kind of basics. You're dry out sooner, warm up sooner in the spring, you kinda get a jump start.
Ken Johnson:You don't have to wait as long for the soil to dry out. It warms up a little quicker. And that's kind of across the board, one reason why people do it. If you've got soil that's contaminated, heavy metals, lead, something like that, you can put this these raised beds in. And a lot of times, they'll put some cement geotextile fabric on there and have a barrier in between the contaminated soil and the soil they're bringing in, allows you to grow in areas where you potentially have contaminated soils.
Ken Johnson:You have poorly drained soils, you know, standing water, stuff like that. Again, raising that soil up off the ground helps it drain. It allows you to grow in areas where you could potentially have poor draining or probably don't want it in standing water, but areas that drained, slowly or just really other potential soil problems, a lot of compaction. You don't have to deal with breaking that up. You don't have somewhere to grow, like, soil available to grow in, you know, up in like Chicago, you know, core team meeting we had up there, I don't know how many years ago now.
Ken Johnson:We went to several community gardens that are growing on asphalt, back top parking lots, stuff like that. So you can put that raised bed there. Again, usually, you're putting some kind of lining in between that, but you're filling that, and now you're you're able to grow plants, in areas where you wouldn't otherwise be able to because of that impervious, surface there. You know, physical mobility issues, if you have issues with with bending, things like that, again, you're raising the soil up off the ground, can help reduce that. And and, really, you can build raised beds pretty much as tall as you want.
Ken Johnson:You know, there's gonna be some some limitations there. It can be very expensive to do that, but you can raise them up off the ground. You know, it could be four inches. It could be three feet. You gotta fill that, but, you know, you can raise that up so you're not having to bend.
Ken Johnson:Or if, you know, wheelchair access make it easier for for people in a wheelchair to access that stuff. So there's, you know, quite a few different advantages to to kinda raising that stuff stuff off off the ground. Mhmm.
Chris Enroth:Yeah. I think especially the mobility issues, you know, one of our vegetable gardening classes, when you're talking about raised beds, we're talking about also container gardens. The topic of salad tables comes up. I think that's what they call these sort of raised platforms that you can kind of wheel underneath, and it's like a a table, And and it's, you know, rectangular shaped and you can grow vegetables in it. But I still think we we we sort of came to the consensus on that as more of a a container system for the salad table.
Chris Enroth:You know, usually with our raised beds, we are connected to the ground in some way. That, you know, we might also we might have that geotext fabric underneath there to make sure that we're not getting any contaminants or nothing leaching upwards from the soil or pavement beneath. But, yeah, it's raised beds. We're really looking specifically like this is has a it is resting on the ground, essentially.
Ken Johnson:Yeah. And like, you know, like a a keyhole garden Mhmm. Would be something you could you know, if it's try to see the kind of picture, it's kinda kidney shaped. So, basically, you got you got an area in the middle where you could walk into, or if you make it low enough, you could put a get a wheelchair or something into that, and it's gonna be you can reach that while you're kind of in the middle of the bed. Mhmm.
Chris Enroth:Yeah. And and that's been a huge benefit. It there there is a cost associated with those taller beds, but I know we've done at our Knox County nursing home project site for Master Gardeners, we've built fairly taller raised beds. And just the the kind of mental, sort of just awakening that occurs with someone who's been out inside for a while with with poor mobility issues and can get outside and get their hands dirty, get them, like, all enmeshed in lettuce greens and all kinds of other plants. There's really an awakening of their senses and memories.
Chris Enroth:So they they can be incredibly beneficial from that that mental health standpoint as well.
Ken Johnson:Yeah. But I will say it's you know, there are some some drawbacks to do in raise beds and kinda mentioning if there's the cost associated with constructing these if you're gonna be doing a, one that you're constructing. So the materials to build it, the the soil to fill it, is you're gonna incur some cost there. Maybe because they do drain, you know, quicker, that's it can be an advantage, can also be a disadvantage. A lot of times you're watering these, a little more frequently than you would in an in ground bed, just because they're they're draining much quicker, especially if you're not getting a lot of rain or it's really hot.
Ken Johnson:Not as bad as like a pot, but they don't have that kind of necessarily that big reserve of water to pull from like you do in the ground. So there there are there are gonna be some drawbacks, you know, like everything in life, there's there's benefits and drawbacks to everything.
Chris Enroth:It's true. That's true. Well, diving along more into this raised bed journey here, I there's a lot of ways to build something to make it taller than the surroundings. Lots of materials can be used to to build a raised bed. And I did see in a lot of the research the defense for having structural raised beds or confined raised beds, those are a couple different terms, but but essentially building something to hold that soil.
Chris Enroth:Because raised beds is a common practice in commercial vegetable production and even landscape plant production as well, where you have a machine that goes through and mounds the soil up, but there's no physical, like, wall holding that soil in place. And there you know, a lot of those studies show that there's quite a bit of leaching and erosion that do occur in those systems. And then they have you have to have a machine come back and reshape the beds every probably every year, maybe even new each time you rotate in and out of crop. So, you know, require a special mechanical equipment. You you it it eventually settles.
Chris Enroth:You get leaching erosion, all of that. So, you know, we're talking specifically about constructed raised beds. We have frames around them, and these frames can be made out of what I like to use, just wood. I like using plain old pine wood that will rot within five years because I don't care. I'll just rip up that rotten board and and and replace it.
Chris Enroth:But there's not always something what people can do. Maybe you want something that will last a little bit longer. Maybe you would want something that looks better. And so there you know, if we start down this list of materials, the things that we can have are first is just the wood. You can choose between treated lumber or untreated lumber.
Chris Enroth:And when you're selecting that treated lumber, just making sure that you're avoiding any of those reused railroad ties, anything that would have been used in in an industrial sense and railroads is an industrial use of lumber. And so, you know, we don't wanna be using that because the chemicals used in those wood preservatives are not labeled for use in a residential landscape. So I know that there are some people who are very proud of maybe you live in a railroad town, you're you you like the idea of having railroad ties in your yard as part of your landscape. If it is from an actual railroad situation, we it is technically illegal to be using that because they are not labeled for use for residences. They are only labeled for industrial use only.
Chris Enroth:Normal treated lumber though. I guess we should talk about this. In the past, it was CCA, chromated copper arsenate, and that arsenate might trigger a warning in people's heads, you know, arsenic. Some of these chemicals, we do not want leaching out. We also have copper in there, but copper is more toxic to plants than it really is us.
Chris Enroth:And it has to be a pretty concentrated or pretty localized dose of that copper element to to affect that plant. And so but that's that CCA product, that has been phased out for purchase by homeowners. So you might still be able to find that, but again, it's only for those industrial or those commercial applications. It is not something that you can find available at the at the lumber store in in your neighborhood. So what it has been replaced with is ACQ or alkaline copper quaternary.
Chris Enroth:So it still has that copper in there. I know some people are still a little concerned about copper in treated lumber products, but again, it is, you know, it is more toxic to plants than us. So it it is something if your plants start declining because of copper toxicity, you know, then you could start start worrying about that. But it it the leaching of those elements don't necessarily spread throughout the bed. It's very localized right next to the soil against those wood products.
Chris Enroth:But I use untruth oh, go ahead.
Ken Johnson:Ahead. I'm sorry. For for that, there is Oregon State. Some people did a little study in that, and we can put a link to the to the write up they did. And it's only moves, I mean, like, an inch or two from that board into the soil.
Ken Johnson:Like, when they tested in the middle of the bed, there was no excess copper. And even the the excess they found wasn't wasn't very high. So you're more than likely I can say never. Get myself in trouble. But more than likely, you're not gonna have any issues with with copper, toxicity coming from from your boards.
Ken Johnson:Mhmm.
Chris Enroth:Yes. And I use untreated wood for my raised beds. You could do cedar, which is kind of an is a naturally rot resistant, but I live in a rural area. They don't even carry cedar boards in our local hardware store, so it is a special order, and they're expensive. So I it again, it's usually a two by six pine board that that I'm using untreated.
Chris Enroth:So do you do you use raised bed, wood material for your raised beds, Ken?
Ken Johnson:Yes. We've got some some wood raised beds, and we use pressure treater pressure treated. And we've had those for some of them about eight years now, and we don't have any no issues with with the wood anyway. Mhmm. Put it that way.
Ken Johnson:Yeah.
Chris Enroth:I I'd say we use untreated pine. We installed our raised beds in 2017 no. 2016 no. 2017. And probably in 2022, we that's when we started swapping things out.
Chris Enroth:You know? I was like, oh, yeah. This board's pretty rotted. Pull that out. We swap that out.
Chris Enroth:The only thing left behind in some corners was, like, the wood screw that everything else totally rotted away. And but and we just slap back on a few more a few more pine boards. So, yeah, I can find some pictures of that. We did order some cedar boards for some of these raised beds. And, you know, they're not rotting as quickly, but they are still decomposing.
Chris Enroth:You can tell they're much you know, you could if I kicked it really hard, my foot might go through it or something. But and there's a lot of warping that seems to have occurred with those cedar boards. So yeah. But but so I would say wood treated, untreated might be one of the most popular materials for building your raised beds. But I have used logs also, just fallen trees out of the woods, pulled those out.
Chris Enroth:And this was for a raised bed area at my parents' house, and we shaped a a nice little woodland garden bed, and we filled that with some fill dirt. And so we have used something like just fallen trees for raised beds. And that's something where as they rot, it actually adds to the character of the garden. And so it was it was all done on purpose with the with the hope that they would rot. And if we ever found any more trees, well, we just drag them over and then rebuild the border with fallen trees.
Chris Enroth:So yeah. So lot, I would say, most popular out there.
Ken Johnson:Yeah. And probably the easiest to
Chris Enroth:Mhmm.
Ken Johnson:Find out and probably the cheapest. Maybe not in the long run if you're replacing constantly, but, you know, if you just wanna get started, probably the easiest and cheapest way to go.
Chris Enroth:Yeah. Yeah. Well, there is a hybrid of sorts. There is composite lumber, which that is something I I think I think there's different products out there. Some might be, like, sort of a a mixture or a slurry of plastic and wood wood pulp kind of fibers, which they then extrude into these they look like boards or board like products that you can cut just like a regular piece of wood.
Chris Enroth:And so so you could do some type of a a composite like that and probably they I'm sure out there there's a straight plastic raised beds that you could get. I don't know if I would go straight plastic. It just sort of depends on that material. But but, yeah, there there's also that composite lumber.
Ken Johnson:Yeah. And that's gonna be at least whenever I've seen composite lumber, like deck boards and stuff like that, it is significantly more expensive Mhmm. Than your wood. So keep that in mind when you're when you're pricing things out. As as you're gonna
Chris Enroth:Yeah.
Ken Johnson:Be spending a lot more money on that composite.
Chris Enroth:That's true. And I don't know if we dare delve into microplastics, Kent.
Ken Johnson:Yeah. I don't know if there's been any research done on how much microplastics, something like composite lumber would shed. Mhmm. Yeah. Not to be flipping of it, but it's everywhere.
Ken Johnson:So
Chris Enroth:It sure is. And, yeah, I I don't know. I guess personal decision, you know, you I I try to avoid as much plastic as possible use in in my landscape, but you'll see I'm a total hypocrite when we get to trip irrigation. But, yes, the next material, though, is metal. I see a lot of these for sale these these days, Ken.
Chris Enroth:You know, just these online kits, these metal corrugated looking, raised beds, they they, like, kinda look like those old makeshift, water troughs, and people are using them, setting them out. Actually, there was a recent a video done with University of Nebraska, their wildlife person, had commented that these metal raised beds, it's actually a really good deterrent for voles with a v, that they are not able to climb up these metal sides to get into your vegetable garden. Now I don't know if that means could they burrow under and go up? That might maybe. Or maybe if you bury the sides a little bit, that would prevent that.
Chris Enroth:So but metal has been very popular. I know you have some metal raised beds at Luukman Gardens.
Ken Johnson:Yeah. So, yeah, we we started with some wood beds. They've only lasted two years before they started falling apart, so we converted the metal raised beds. And, yeah, they're the ones we've got, that's just panels that they screw together. So, like, you know, the that bolt and some some washers.
Ken Johnson:So you can kind of, to an extent, depending on what kits you get, customize how long it is, how narrow it is. It's usually two what do I have is two, two and a half feet or, like, four feet wide. So, again, depending on depending on how you configure it. Yeah, you can you can figure it multiple ways. You can buy multiple kits and make a 30 foot long bed, with those if you wanted.
Ken Johnson:I will say, I can throw some pictures in here. We do have some taller ones, and they were a little bit shorter. They didn't come with any brace rods to go across, and we're starting to get some bulging. Some of those especially when ones that were didn't get the ground perfectly flat. It's a little bit of an angle.
Ken Johnson:We're getting some of the sides starting to bulge out. So we've gone to the ones the kits that are a little bit bigger, little more expensive. You can make longer beds, but they come with brace rods to help kind of prevent some of that that bowing. Keep that in mind. There's numerous companies out there, that'll sell them.
Ken Johnson:They come in all kinds of different colors. You know, kind of a white, green, brown, tan. I'm sure there's probably more out there, but those are the ones that you kind of the most common colors, that you see there. And then various heights, you know, eight inches, 24 inches, 32 inches. So there's there there's a lot of different options out there when when it goes about a lot more than there used to be anyway.
Ken Johnson:And
Chris Enroth:then the other material, probably, maybe one of the more most permanent out there is using something like stone or rock. And whether that is, like, a a dry laid stone or maybe you use some type of mortar to hold it in place, That that that's definitely an option, especially for folks who live in, you know, rockier parts of the world, you know, looking at people over at the Flint Hills Of Kansas where I used to live, where you dig a hole and you hit a rock. So it's really hard to have basements out there without digging a bunch of rock out. So, you know, if you have access to a lot of just stone naturally around or if you go buy it or or wherever you might find it, I I would say there are, I think, some rules in some states where they don't want you pulling stones out of natural areas. So just make sure that you're adhering to all local rules and laws about where you harvest your rock or your stones.
Chris Enroth:But then also, we have brick and concrete construction supplies that you can use to to to build your your your raised beds.
Ken Johnson:Yeah. I think that's another pretty I I would say it's probably a little more popular with, like, ornamental type veggies. I don't It just seems more permanent than you would have, like, for a vegetable garden. Mhmm. But, yeah, less cinder blocks see those quite a bit or even, you know, brick raised beds is, you know, houses being built.
Ken Johnson:Those are built within, like, around a patio or or something like that. But, again, they're fairly I would say fairly fairly cheap depending on on what brick or or concrete block you're choosing, but, you know, it's pretty affordable still.
Chris Enroth:Mhmm. Well, Ken, in our our our boundless pursuit of growing plants, we have built many raised beds or or put them together. Whether or not you read the directions, I don't know. I try to as often as I can. So do we have any tips, or should we be should we walk people through, like, putting one together?
Chris Enroth:Or, like, you know, what what are some of our construction tips for folks?
Ken Johnson:Yeah. I think the the big one is kind of the corner bracing. And if you're building a longer bed, make sure you've got bracing. That's usually four to six feet so you don't get that bowing. So it's another tower or this in the tie rods, for your metal raised bed, what have you.
Ken Johnson:But usually for your for your wooden raised beds, you know, if you're doing it, it's a real simple one. Two by fours, two by six, one by whatever. And you've got your your long, your longer boards, making sure you're screwing those into, a corner piece. A lot of times people use a two by four or four by four in the corners. Screw into that.
Ken Johnson:There's brackets that you can buy, for that purpose. But really kinda anchoring those corners well. For the raised beds, we have the wooden ones. We got a concrete blocks that have notches in them that you can slide a two by six into. And there's a hole in the middle that you can drive rebar through.
Ken Johnson:So that's how we built ours. So with no screws or anything like that like that in there. And then when we built it, we built some and made them we forgot to account for the box when we built them. So we made them four feet wide on the box, add another four or five inches on each. So it's more like four and a half, almost five foot to the middle.
Ken Johnson:So it it makes it a little difficult, to reach the middle. So when you're building these, typically, I don't recommend any wider than four feet, if you can reach from all sides. If you can only reach from one side, looking at more two feet, that's how far somebody can reach. If you make it wider, then you gotta start walking in it, which kinda defeats the purpose, in a lot of cases of building a raised bed. So checking your dimensions and just making it sturdy enough such your boards aren't bowing out, I think would be the big things.
Chris Enroth:Mhmm.
Chris Enroth:No. I I think that is the the making sure you don't step in there is a very important tip for us because if you build, especially, a tall raised bed, it's really hard to get a tiller up there to relieve that compaction that your feet cause. So, yeah, the whole idea of that raised bed is that we don't have to walk in it. We don't have to compact that soil, and it becomes hopefully a better medium for plant growth with the root system. But we'll talk more about that, I think, in in the fill part here just coming up.
Chris Enroth:But maybe a few other things, like, definitely making sure we fought Boeing a lot with our some of our raised beds. We did take some pieces of two by four, cut, like, an arrowhead shape on the bottom of them, screwed that to the side of the wall of the the weight raised bed, hammered that in the ground. And that lasted for a little bit, but of course, it rotted, and then Boeing, you know, kept happening. So you you know, we now use a those foot long landscape spikes. Like, they look like giant nails.
Chris Enroth:We drill a hole through there, through the board, and we we put that into the ground. You could also use rebar. You could put pipe straps on the inside, and that rebar could just slide right through that pipe strap and hold that wall in place. The other thing that some of your, like, pipe straps and and other fixtures could do is that you could design your raised bed to then have, like, a PVC or metal conduit then slide onto that rebar or into that pipe strap. And then you could put plastic over top.
Chris Enroth:Boom. You have an instant low tunnel, you know, instant season extension. Also, we're gonna get into to the drip irrigation side of things, but as you're putting these beds together, think about how you're going to be getting water to them. If you're going to be using drip irrigation, you know, where is that that plastic pipe going to come up? Is it gonna come up the side of the bed?
Chris Enroth:Are you gonna install it on the in in the inside of the bed? Just things like that to consider when building those raised beds and small few fancy extra add ons. And I guess the other thing is it it is important to know when you are, using lumber or wood, screwing into the ingrain of lumber is not a very strong connection, and so that's why those corner blocks are so important, as Ken mentioned. But it it it will help in the very short term, keeping those boards together. If but but you really need that corner blocking because a a screw in the at the end of the wood just will pull right out over time.
Ken Johnson:Yeah. Or look for the there's a lot of garden catalogs that will sell just like the corner bracing kits Mhmm. And stuff too. They're usually metal or or something like that if you want. Maybe something more a little more aesthetic than a a four by four cut off in the ground.
Chris Enroth:Right. Yes. And I'm sure everyone, you know, listening, watching, you've you've probably built raised beds yourself. So if you have any tips or things that you've learned over the years, please feel free. Leave those comments down below.
Chris Enroth:Yeah.
Ken Johnson:So we teased fill material. And this is one thing I at least hear that in Jacksonville, I've always kinda struggled with, is finding good fill material. So I know when when we first built our raised beds, we got a load of of topsoil. Do that in air quotes. Because when we they delivered when it got delivered, it was more like fill.
Ken Johnson:There was rocks and bricks and glass and slag in there. And we're doing this for vegetable gardens, like, not not growing vegetables in that. We dug it all out. Use it to patch holes in the guard in the yard. Took a while to get some grass and stuff growing in there, so I'm glad we weren't growing vegetables.
Ken Johnson:But, you know, you can buy find bagged stuff at the box stores. A lot of that's really high in organic matter, of peat Mhmm. Forest, my product, I think is what they call it, mulch. So that that you're gonna get a lot of settling, with a lot of that stuff. So I think a lot of times depending on where you live is gonna dictate a little bit what you're gonna be using for fill material and and the quality of that.
Chris Enroth:That
Chris Enroth:is true. Yeah. And it and especially, like, if you can use the soil where you're growing, the native soil, that might be more of an, like, an ideal situation. But you might be building a raised bed because it's contaminated or because there's some other issues, compaction, pH, whatnot. So but in some research that I was reading through, one of this was it was like a master's thesis.
Chris Enroth:I think it was from Georgia where this student looked at every raised beds and the fill composition, and they grew kale and basil in three different crops three different crops. So three iterations of that. I'll probably get some of these incorrect here. So maybe I should pull this up to actually read it. But she did look at compost only, native soil only, pine bark only, wood fiber mulch only, so basically wood chips, and then fifty fifty combinations of each.
Chris Enroth:And so it was what this person had found. And remember, this is one study, one season, one person doing this. And but what they found was that the compost overall performed better than any of the others. However, once they got to the third cropping event of the season, so they've done their first one, composted good, second one, composted good, were late in the season, the native soil was just as good as the compost. So they were statistically identical, for that third that that third round for that season.
Chris Enroth:So, really, what the conclusion of the study was is that maybe an ideal fill for this would be something fifty fifty compost native soil mix. And also with the big caveat that, hey. We need to keep researching this because a lot more people are wanting to do raised bed gardening in their yards. And I'd say, Ken, you mentioned settling. It's such a pain in the neck, isn't it?
Chris Enroth:Raised beds, they always settle. It's because a lot of them are mostly organic matter, and organic matter is not permanent. It goes away. It gets used. It goes up in the atmosphere.
Chris Enroth:The we lose it. Soil, native soil, one component of that native soil is minerals. Minerals do not go away unless through wind or water erosion or a shovel. But, you know, if none of those forces act on it, it stays there. And so that is one of the things that can help limit or at least reduce some of that settling is to have actual mineral soil in there, that sand, silt, and clay.
Chris Enroth:Now when we go in and we buy mineral soil, native soil, you know, we we do have structure, but a lot of that structure has been lost in that process of digging it up, putting it in your your in your raised bed, mixing it with compost. So I've lost a lot of that structure. It can be rebuilt over time, but you're again, you're gonna keep getting that settling. You're gonna keep getting that, so you have to keep adding to it. So for our raised beds, we did a fifty fifty mixture.
Chris Enroth:And that first year first two years, actually, we did to cover crops underneath our plants. So we had tomatoes growing up, and then underneath our tomato plants, we had cover crops. And I feel like that helped to stabilize and create a little bit of structure in the short term. And, no, there's no research that I'm quoting on this one or at all. So it's just something we did.
Chris Enroth:Like, well, we gotta do something so that, you know, it doesn't drain so quickly and that we we don't settle so quickly. So cover crops seem to do a little bit of help. We did do a, again, anecdotal study in that we had raised beds in our high tunnel. One was filled with potting soil, basically a peat based mix. One had, compost, and another was just the native soil.
Chris Enroth:We did cover crops on them, throw a picture up here of that cover cropped, raised bed. And we then planted sweet potatoes that next year, and it really seemed like the sweet potatoes and the native soil seemed to do much perform much better. Compost did pretty well too. The potting soil did not do well at all. It was just too sharply drained.
Chris Enroth:It just dried out too quickly.
Ken Johnson:Yeah. I think if if you live in a probably a little more populated area, you know, lot times if you're getting, that that raised bed mix, lot times, it's some kind of organic matter, maybe some topsoil, with sand mixed in to kinda help with that that drainage because you lose a lot of that that structure. There's there's again, depending on where you live, there's probably kinda special raised bed mix that you can get from nurseries or or garden centers, stuff like that. But Yep. If you're in a more rural area, at least in my experience, you're little more limited as to what you can find.
Chris Enroth:Yeah.
Chris Enroth:Yeah. And that that is one of those downfalls with raised beds is you are now starting off with no soil structure. You the soil has these pores in it. Ideally, a good soil has 50% pore space. 25% of that is water.
Chris Enroth:The other 25 is air, and the rest is mineral and organic matter content. So that's the whole soil pie for the ideal loam soil. But the soil pore sizes, they vary in a good soil structure. There's teeny teeny tiny ones and there's big ones and and everything in between. And because you have different pore sizes, you are able to hold more water in those smaller pores.
Chris Enroth:It doesn't drain through gravity as quickly, or the roots can't extract it as easily. And so you you just have you have better water holding capacity, and it just doesn't drain as fast, and that just doesn't exist in in raised bed soil right off the bat. It I would imagine, kinda takes years and years to build some type of structure like that in a raised bed.
Ken Johnson:Yeah. And especially as, you know, talking vegetable gardens, you know, we're only we have stuff in there for couple months out of the year, and we're removing it. Ornamental bed where you get constantly have roots in the ground, you may be building that structure up a little bit faster if you're putting cover crops, which I I've started putting cover crops in our raised beds. Just basically taking a year off, let the rye grow up and die, just just kinda leave it, let it break down. And I kinda hopes of building some of that structure on ours.
Ken Johnson:But the more you can have roots in there, you know, the better. Because as they're releasing those chemicals that make, you know, the stick the soil particles together and stuff, you kinda hopefully speed up that process of that that structure forming a little bit. Mhmm.
Chris Enroth:Yeah. Oh, one question I always get from folks. They've built a really tall raised bed. They wanna know, can I put, like, plastic jugs or gravel or something cheaper in the bottom half of this raised bed? So do you ever get that question, Ken?
Ken Johnson:I don't know if I have. What do you tell people?
Chris Enroth:Well, I'm glad you asked. What I tell folks is that this is a case by case basis. Understandably, not everyone's budget. You maybe you definitely want a garden. You wanna grow your own food.
Chris Enroth:One situation I'm thinking of, they wanted to grow native perennials in these raised beds. So you gotta go case by case basis. If you really can't if if you do not have the budget to fill your raised bed with all soil, but you're like, I really wanna grow. I'm like, well, I mean, fill what you can and then plant. But if you need to add, you know, a little bit of material on the bottom, I guess go for it.
Chris Enroth:From a plant or maybe a plant health standpoint, that's not necessarily a good recommendation. Because what we want to give these plants is as much soil volume as possible. And so I tell the folks, look. I understand your budget might not you might not be able to do this, but this from the horticultural, like, plant health standpoint, we wanna give them as much root space as possible. And so you maybe I've, you know, kinda said, ah, yeah.
Chris Enroth:Sure. I guess throw a couple empty milk jugs in there. It's gonna hurt. But again, with saying, like, but the the ideal thing to do is not do that. And so I I would say, you know, give them as much roots root space as possible, especially those native perennial plants that they wanted to grow.
Chris Enroth:I mean, they got deep root systems. They want they they need room to grow. So yeah.
Ken Johnson:So yeah, raised beds dry out quick enough as it is, the less soil you have in there, the more that more quickly that's gonna dry out. So take that Yeah. In mind
Chris Enroth:Oh, do oh, and the we talked about geotextile fabric for contaminated soil conditions. But, I mean, if you don't have the that site constraint, is it necessary to lay cardboard on the bottom or kill the grass, or do you need to do anything?
Ken Johnson:I'll I'll say for my raised beds, we just build them and fill them. I don't kill the grass beforehand because that grass probably is not gonna grow through, in our case, 10 inches of soil. And if it does, oh, I'm kinda the animal you probably deserve to live if if you push
Chris Enroth:Give it a trophy! Yeah.
Ken Johnson:And it's, you know, it's it's gonna be pretty easy to pull if it managed to grow all the way through that. And it's probably not doing all that well. So, yeah, I don't I don't bother killing stuff off before I mean, you can, but if Yeah.
Ken Johnson:Maybe if you've got, like, a you know, you're only doing a two, three inch raised bed, you may benefit a little bit from killing it off first. But if you've got it deep enough personally, I don't see the I don't know if seeing the point is is the right way to put it, but I don't think it's worthwhile to to to smother everything and then fill it. Right.
Chris Enroth:Yep. I agree. I'd say maybe the the only thing you would do if it is a really shallow one, scalp scalp the lawn. If you're going on a lawn, just take your mower, drop it to the lowest setting, and only in that footprint of that raised bed, just scalp it down. That's the only thing I could think of in a really shallow raised bed.
Chris Enroth:Anything more than, I'd say, three, four inches should get killed by what you're putting on top of it.
Ken Johnson:Yeah. And with that cardboard, depending on what's coated with it, may just shed water, which Yeah. May cause you some problems too.
Chris Enroth:We don't want that.
Ken Johnson:Yeah. And it's not gonna break down right away either, more than likely.
Chris Enroth:Mhmm. Mhmm. Yeah. Well, we've I guess, have we accidentally gotten gone into maintenance? Because our our next topic here was maintenance.
Chris Enroth:But I don't know. I so we do the cover crops. In terms of replacing fill, we we do use wood mulch to mulch our our garden, and that just sort of breaks down over time and just we just sort of keep adding to it. So, you know, if I had we we used up all of our native soil that we had, so we don't really have any of that to add more to it unless we go buy some more. And and so that you know, it's really just we refill our raised beds with mulch, and that decomposes, and it just sorta just keeps building up that organic layer on top.
Chris Enroth:Do you do anything to fill them up?
Ken Johnson:Yeah. A couple of ours, the ones we've had for seven or eight years now, they've settled quite a bit. So we've actually gotten some bagged raised bed mix put in there. And I just use, like, a a garden fork to turn it over a little bit to mix it up, but I'm not I'm not tilling. I don't know.
Ken Johnson:I'm beating up that soil. I'm just kind of incorporating it a little bit. I don't know if I should admit to this, but sometimes pots when we're done with soil and pots, we'll just dump them in there. May not be the the best thing to do, but that's what we do. Well, that's what we do.
Ken Johnson:So do it at your own risk. Because through there is a potential if you got pathogens or something in there, you know, you're introducing that into your raised beds. But if it's questionable, we don't. But a lot of times, we'll just plant died for whatever reason, didn't watered enough. That pot will get dumped into the raised beds and Mhmm.
Ken Johnson:And stuff. So but we do have to probably next spring, we'll probably be buying quite a bit of of raised bed mix. Because some of them have they're two by six boards. Some of them settled down below that two by six board. So it it's time to do some some major replenishing.
Chris Enroth:Well, we also had mentioned this multiple times about how these raised beds are very quickly draining. They dry out very very fast. At least here in for our our gardens in Macomb, we have gone to drip irrigation, and I don't know if we could do it without drip irrigation. Otherwise, we would need to have someone out there almost daily watering. What do we have?
Chris Enroth:Over 20 raised beds out here. Because we are growing, for our food donation garden here, we are growing on an old gravel driveway. It was the only place that we were able to get approval to put our garden, on our site. And, we put the shovel in the ground, and it didn't go very far. So that's why we decided to go the raised bed route.
Chris Enroth:And, but they do dry out so fast that if we did not have drip irrigation, I would lose volunteers immediately because it can be hot, and it is not fun watering this big garden when it's so hot. But it's all automated. We have it on a timer. It kicks on twice a week when it's hot and dry, and it irrigates for about an hour. Hour actually, I have it set to an hour and five minutes.
Chris Enroth:You can calculate that based upon the flow rate of the the drip line that you select, you know, how many gallons per minute does it does it let out. And just sort of over the years, I've just figured that an hour is a good amount of time. You go out with your hands or you could use a screwdriver, trowel, or something, and you probe around after you've run that drip irrigation system just to see how deep it's gone. And, you know, you know, is it penetrating down from the top of that raised bed down to the bottom? That's really what we wanna see.
Chris Enroth:We don't wanna have any excess water draining out of the bottom necessarily, but that that that is the is the time that works best for our soil mix as it is now and the size of our garden and the flow rate of our drip irrigation system.
Ken Johnson:Yeah. So the the stuff we have at home, we hand water. Should get your irrigation set up. And at Leuquen, it's the same thing. We hand water that I usually go out in the mornings, spend half hour or so watering if it needs it.
Ken Johnson:And and a lot of times later in there because lot of the raised beds we have aren't very tall. So as those plants get bigger, they can get down into that that native soil. And it's not this time of year, it's not quite as bad as early in the spring, early in the summer. You know, if we get dry, they'll they'll need a little bit more. I must say there's was it last week I was watering?
Ken Johnson:Started watering and then immediately the water started coming out the bottom. That that soil most of it's bagged, you know, like potting mix or the raised bed mix, which is kinda glorified potting mix. So it dried out pretty quick, it just kinda ran through. So
Chris Enroth:Yeah. Needs to rehydrate so that it doesn't shed water. It it absorbs water.
Ken Johnson:Yeah. But, yeah, the the plants didn't look considering how quickly that drained through there, they didn't look bad. So I'm I'm assuming a lot of those are probably down into the to the native soil now and may able to pull some water from there. Mhmm. Yeah.
Chris Enroth:And I I would say drip irrigation is not difficult. Most companies anymore, you pick out whatever brand you want. You can go online, and they have videos that show you how to install them, how to how to set them up, how to maintain them, and how to prep them for winter. Biggest tip on drip irrigation when it comes to winterization, any hard plastic fittings, it works best to get them out of the garden. A lot of flexible plastic might be okay, especially if you blow out your lines, or you drain them properly so that there's no water sitting in there when it freezes.
Chris Enroth:But even that hard plastic, it I've just you go out in the spring, you put everything together, do your first test, and there's these geysers that pop up randomly in the garden where you have these tees and elbows and stuff like, oh, I was just lazy last year. I didn't take off those hard fittings, and they they split. So yeah. And and they are plastic. You know, for the most part, it's all plastic materials.
Chris Enroth:And I said I try not to use as plastic in the in the garden, but that's one of the things where that is the exception to my rule because, again, we could do it without it.
Ken Johnson:Yeah. So I've just yeah. I'd say drip irrigation, do it by hand. Just if it gets dry, you know, we typically rain it for an inch of water a week. If you're not getting it through rain, plan on on watering your raised beds or keep an eye on them.
Ken Johnson:Go out and look at the soil, stick your finger in there, and see if it needs it.
Chris Enroth:Yep. And this summer, our irrigation system has been off most of the time. We have not had to water, but maybe a handful of times earlier in the year. Well, I guess, what are we watering in these raised beds, Ken? What what can we grow in a raised bed?
Chris Enroth:Is this just like an in ground garden?
Ken Johnson:Yeah. I'd say, again, this is depending on on the the size of your raised bed and and really kind of the the plant. I'd say just about anything you can grow in the ground, you could potentially grow, in a raised bed. Now on the vegetable side, you know, for for me, I carrots, potatoes, I've really got it where I only grow those in raised beds because we have fairly heavy soils, and it's just easier to grow those, in raised beds. It's easier to dig them.
Ken Johnson:Half time you have to dig them, you can just pull the carrots straight out, and stuff. Don't get really, disfigured, carrots unless I don't fit them out. That's really the only time I get weird looking carrots now. Because that could be because that is a looser soil. Same thing with potatoes.
Ken Johnson:It's a lot easier to dig those in in the soil. It's got a lot of clay in it. A lot easier to clean them too. Well, that way too. So, you know, for our for our root crops and stuff, I I think raised beds are really good, especially for most of Illinois where we have or a lot of Illinois where we have heavier soils.
Ken Johnson:The one that's commonly you can kinda kinda shy away from growing in raised beds on the vegetable side, like sweet corn, just because we need blocks of that. Now there are some shorter types. Those are the on deck type that only gets, what, two feet tall or something like that. So, you know, if you can, you know, big enough raised beds where you can put that in box, you know, that could be a potential. Some of the larger vining plants, you know, pumpkins and stuff, you could plant them in the raised bed, but the more likely they're gonna spill out of that, into the rest of the landscape, which is fine.
Ken Johnson:But if you don't want that, then you're looking at trellising them, or something. But they're gonna more than likely take over that raised bed unless you're growing some of the water some of the melons, you have more dwarf sizes that you could put in there. But yeah. In our in our garden, vegetable wise, root crops, a lot of herbs, stuff like that is what we grow in there.
Chris Enroth:Yeah. We we also treat it pretty much like a a a typical garden that we have a lot of tomatoes, peppers, do cucumbers. We also have a lot of trellises where we are along with groundhogs. So the foun fencing to keep the groundhog out is also double does double duty as trellising for some of our cucumbers. We do pole beans instead of bush beans.
Chris Enroth:And because with that trellising system that we've we've built for our raised beds, bush beans would would take up more space than probably the amount of beans that we could harvest in a narrower bed. So instead of growing more horizontally, we're growing more vertically, with a lot of our crops. And so, yeah, we we we use we use fencing quite a bit in our our garden to grow taller as opposed to growing outward and sprawling. So, yeah, no pumpkins for us. We do we do cucumbers sometimes on the ground.
Chris Enroth:We do we've done one we have one raised bed with just sprawling cucumbers in it, and it's growing cucumbers, but the ones growing on the fencing are still nicer. Yeah. So, yeah, a lot of the vining stuff, we we have to trellis it upwards.
Ken Johnson:Now you mentioned the raised beds keeping voles out. They don't do anything for groundhogs. They do not. Okay. How how do I look when they've eaten all my peanuts and carrots?
Chris Enroth:This darn groundhog. Actually, in our garden shed at the, here at at the extension office, it has burrowed underneath, and it has chewed a hole through the the floor of the garden shed, and it has now decided it it likes living in the shed as opposed to under the shed much better. So wildlife. Well, Ken, we do focus a lot on vegetable growing with our raised beds. But, you know, I mentioned before native perennials.
Chris Enroth:You don't have to just do vegetables in our raised beds, especially, you know, if this is for someone who, maybe can't stoop or bend down as well, and so they wanna grow up a little bit higher. Works really nicely around, like, patio settings. Growing ornamentals, flowers in in raised beds. Dare I say certain perennials, maybe even woody perennials like shrubs. Is is that possible?
Ken Johnson:Yeah. It is gonna be possible. Yeah. It's I I think the kinda the one issue I can think of with with growing more perennial stuff in raised beds is that soil settling. So probably, you're just gonna have a hard time adding more to that.
Ken Johnson:You may just have to live with the settling, to some extent because you don't wanna bury, those perennials. But, yeah, you could certainly certainly do that. And even we're talking about our minerals, but, like, something like a blueberry where we need those really amended soils, acidic soils, which we don't really usually have. In Illinois, that would be a good option. You know, if you don't wanna grow in a container, build a raised bed for your your blueberries or those those perennials that need a little more modified soils or soils that we don't we can't provide in a lot of Illinois.
Chris Enroth:Yeah. And I maybe in those situations, I would suggest to folks look more at using a a native soil, fill, you know, instead of a fifty fifty compost native soil, maybe push that, you know, more 60% native soil, maybe 75% native soil. It's gonna be heavier. It's gonna be more expensive. There's gonna be a lot more shrink swell also with native soils because if you have native soil, at least here where we're at, you have clay.
Chris Enroth:Clay, you know, there's a lot of shrink swell when it comes to when it's from from dry to wet. So you might have to have beefier walls, you know, you know, maybe thicker, lumber, maybe like a four by four or six by four, you know, basically larger post like lumber, for those, you know, more structural plants like a blueberry. Because they make these patio blueberries, which you can grow. They're cute. They have good fall colored, pretty white flowers in the spring, and and and fruit blueberries.
Chris Enroth:So, you know, and there's other other shrubs and things that we could, you know, talk about with these. I'm thinking of aronias, those those low scape mounds that they also have these days, some of our fibrinums that are, you know, can be planted around there. So in essence, what we're saying, you might have to have sturdier raised beds if you're looking to do, like, perennial or even woody shrubs in these beds.
Ken Johnson:And up the regular soil content.
Chris Enroth:Mhmm. Yes. Yep. Well, that was a lot of great information about growing in raised beds, building raised beds, how materials what materials we use to to put them all together with a good growing podcast production of University of Illinois Extension, edited this week by Ken Johnson. Hey, Ken.
Chris Enroth:Thanks for hanging out with me today, talking about raised beds and editing for two weeks in a row. I do appreciate that. Thank you.
Ken Johnson:Yes. Thank you. One of these days I'll get my I keep saying this. I'm gonna get my drip irrigation set up for my raised beds.
Chris Enroth:Just give me a call. I
Ken Johnson:keep saying it, I'll speak it into existence one of these days. Mhmm. Let's do this again next week.
Chris Enroth:Oh, we shall do this again next week. Well, one of the components of a fill for raised beds is compost. So let's talk about compost next week. How do we make it? We will be diving into the old compost bin and see what's going on in there.
Chris Enroth:Listeners, thank you for doing what you do best, and that is listening or if you're watching us on YouTube watching. And as always, keep on growing.
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