Wisconsin Public Television University Place  Square Foot Gardening Lisa Johnson  2/9/13 UP834  cc >> Wow, we've got a full house here. My name is Lisa Johnson, and I am the Dane County UW Extension horticulture educator. And I'm going to be talking to you today about square foot gardening and raised bed gardening and container gardening. So, I forgot about my handy dandy remote here. Are there any people in the audience that have already done square foot gardening before? Okay. All right. Well, it's really not a very difficult process. In fact, the reason that I have also added raised bed gardening and container gardening is because it only takes about 10 minutes to tell you how to do square foot gardening. [LAUGHTER] So, in order to fill the time, we are also going to talk a little bit about those other types of raised bed gardens. So, the square foot gardening idea was birthed by Mel Bartholomew, and it started back in the '70s. 

He wrote a book which was called, imaginatively enough, Square Foot Gardening, and he now has a new edition that is out, and the idea of it is that it is simply an intensive production system. The idea is that you can by using this system grow about five times as much food in a smaller space than you would be able to in a typical in-ground garden. Now, there are some issues that can come up with this which we will talk about later, but the idea then basically is you build yourself a four by four raised bed and you divide it into one-foot grid sections, and there, voila, you have it, square foot gardening. Not too difficult. I should also mention that the Square Foot Gardening Foundation exists. It's a non-profit. They do all kinds of teaching in many different countries. They give grants. They support community gardens, etc. and if you're interested in learning more about it, I've provided you with a website there. I should also mention that this presentation is on the Garden Expo website. 

So if you want a copy of it, you can go there. If you don't have a computer or a printer and you're not able to print it out, you can contact me at the Dane County Extension Office, and I will get you a copy. So, the style with these raised bed square foot gardens is up to you. I have seen even things like dresser drawers taken, and as long as you have some holes punched in the bottom so that they drain, you can even use something like that. The idea with the square foot is that you don't build any wider than four feet, and, generally, you use boards that are going to be about six to 10 inches in width because, in general, you're going to be growing vegetables in these and, in general, most of the vegetable root systems aren't much deeper than 10 inches. So you don't need to do anything with the ground, which actually saves a lot of time. One of the things that is wonderful about this system is that you don't have to till every year and that if you have a small yard, you can still produce as much food as you would produce in a larger in-ground garden but in a much smaller space. And if you have trouble bending over, having it raised really can help you as well. Again, we're going to talk about some of the issues. Some of the issues are that if you're trying to grow a bigger crop, such as a cucumber or a tomato, you may have a little bit of difficulty in that those crops tend to be rather large and can overpower the rest of the crops in your small spaced square foot garden. 

So, we'll talk a little bit about variety selection, which is one of the things you can do. Okay, these are a couple of examples of the ways that raised beds can be put together. And there are, on Mel's website you can get a kit, and if you're handy, you can, again, build your own. The bottom shot is one that's at the Dane County Extension Teaching Garden and our Children's Garden. We opted not to use the four by four arrangement, but we just made raised beds. You can certainly cut those boards into four by four squares if you wish. What we used were decking boards that are made out of a composite of recycled plastic and wood. The nice thing about that is that it's never going to rot. I don't have to worry about replacing it. Whereas, if you have pressure treated wood or cedar or something like that, eventually it might rot. 

So, again, many different ways that you can put these things together. You can see that in the second row there of pictures, or the second one down, that they've used corner pieces. And we used stakes in the middle and at the end of ours because ours, not being square, we needed a little bit of support in the center. You can get those decking boards, by the way, at any home improvement store. You can get them either hollow or you can get them solid. They've gone up in price a bit, and with the hollow ones, although they're cheaper, you have to buy end pieces so you don't get German yellow jackets nesting in them, which is an important point. And you also, with the hollow ones, it's best to support the sides a little bit because they tend to wow out a little bit. Whereas, the solid boards don't do that. Okay, so, again, some of the benefits, besides the fact that you get to produce a lot of food in a small space, is that you don't need tilling. You can use weed barrier fabric at the bottom. 

Although, it's not necessary, really, when you have 10 inches of material or six inches of growing media in there. Most weeds can't come up through that. If you do have raspberries growing nearby though, the raspberries will come up through that very nicely, so do make sure that you use, the weed barriers didn't stop raspberries but site your raspberries away from your raised beds. Now, with the grids, some people like to have them be permanent, and other people like to have them be able to be removed. So, you can use string if you wanted to, for example, or you could use any number of different kinds of materials to make the grid. And I'll talk more about that in a second. You can also, as you can see on these beds in the picture, and I've included the websites, by the way, that I got these pictures from in case you want more inspiration or want to see more examples. You can go and look at those. But you can see in a couple of those, they've added trellises in the back. So if you did want to grow something like a bush cucumber or a patio tomato or a crop that can take up some room but can be trellised, then you can put that at the back so that it's not shading everything. 

Now, certainly, when you're planting your square foot bed, you do need to figure out which crops are going to be bigger and which ones are going to be smaller so you don't put the bigger ones on the outside and then you're having to do that sort of thing to try and get through them to get to your other crops. And you don't want the crops that are on the outside to be shaded or overrun as well. So, what some people will do is they may plant one whole bed of shorter crops and then another bed of taller crops so that they get along better in this sort of environment. Again, you can use many different kinds of materials for your grid. Here's an example of one that is made out of pieces of wood, and they're screwed in so that they can be removed at the end of the season. Since the material that you're going to use contains compost and other materials that are going to degrade during the season, you're going to need to add more next season. So sometimes it's easier to add that and mix it in if you can take the grid off. So, some people will just simply lay the grid on the soil so that they can get the spacings right. Other people, again, will maybe screw it in or nail it in and then just remove it, or leave it there. Either way, it's fine. 

Some people like to use strings and then they just use nails to wind them around. If you are going to use some system like that where you have nails sticking up, I would recommend that you put a cap on them. Nobody wants to get scratched by a rusty nail. Some people will use, actually, spools, thread spools, and that works as well. So you just cut your grid to fit across whatever width you've come up with for your system. Again, the traditional one is four by four, and if you have a four by four bed, you're going to end up with 16 little grid spaces to plant in. Here's some more examples of different ways to set those up. I particularly like that one on the bottom. It's quite a bit of work but really pretty to look at. If you're putting it in your front yard, maybe something like that would be something you want to look at. 

Here's a couple of other examples. And the bottom one that's green is raised so that if you are using a wheelchair or you have difficulty bending over, that one's actually raised up even a little bit higher. And the one on the bottom, I believe also swivels. I know that Shelley Ryan, a number of years ago, did a raised bed video that had what looked like a kid's pool, and you could access it from a wheelchair and it had a handle on it. So you might want to look. I know that's in the archives somewhere because I've seen it out there. So you could adapt the same kind of design for a square foot garden too. Other materials, again, I've talked about the one at Dane County Extension where we're using that composite wood material made out of recycled plastic and wood. You can also even use building blocks. So, if you wanted to get cement blocks or other type of block material, you can use that. 

That would be just fine. Very heavy, but, again, you wouldn't have to replace it in any amount of time. One thing that you don't want to do when you're looking for boards to use for your raised bed garden is you don't want anything that has been treated with copper arsenate. There have been studies, it's not very clear that it leaches into either the media or the vegetables, but it can, when it comes in contact with your skin as the boards start to degrade, you can be exposed that way. If you scrape your knee on it or something like that, or particularly if you have children working around those beds, you don't want to use boards that have been treated with copper arsenate. They do have pressure treated boards. They have cedar boards, and those should be safe to use as well as the decking and the block material. Okay, so, what do we actually use in our material that we want to put in the bed? Well, one thing that you don't want to use is dirt straight from your garden. The reason for that is that, really, a square foot bed is a glorified larger sized raised container. And when you put garden soil in that type of container, especially if it's good old Madison, Dane County, any other part of the state clay, it will tend to turn into a brick, and most plants don't like to grow in bricks. 

So, what Mel, who came up with this system, recommends is that you use some compost, some potting soil, and, actually, I have, on one of the next slides, I have his recipe. You can use straight bagged potting soil. You don't want to use one that's labeled top soil or cow manure or something like that straight. You can certainly mix that in, and I do actually recommend mixing that in, because most of our bagged potting soils are what we call soilless mixes. It's kind of interesting that something that's marked as potting soil really doesn't have any soil in it. But it is nice and it's very easy for roots to grow and it hold moisture well, but it doesn't have a whole heck of a lot of nutrition unless you buy a bag that says it's got a slow release fertilizer in it. Now, you can use supplementary fertilizers if your bagged product doesn't have any in it, and they can be organic. You could use something like fish emulsion or compost tea or you could use any of the traditional water soluble products such as Miracle-Gro or something like that. Or you can use slow release fertilizer yourself. In any case, with the bagged soilless mixes, because of the lack of nutrients, you do need to add some kind of fertilizer because most of our vegetables need that. 

And again, even if you add up to a third of compost, it may not be enough to meet the nutritional needs of those vegetables. Alrighty, so here's Mel's recommendation. He recommends a third compost, a third peat moss, and a third vermiculite. If you take off the compost, the rest of it looks a whole lot like what you might get as a bagged product. The bagged products, though, also may contain things like coconut fibers or other types of organic material that is not soil. And the raised bed garden folks or the square foot garden folks suggest a blended compost also. You can buy that in bags as well. UW Extension, because we're not sure of the analysis of the compost, in other words, how much nitrogen, phosphorus, potassium, etc, it's going to contain, we do recommend adding, if you're using a soilless mix and even a soilless mix with compost added to it, we do recommend that you do add a little bit of extra fertilizer. These are some of the resources that are available about soils through UW Extension. We have the one on organic soil conditioners which includes things like --, peat moss, etc. here are also some that you can find at our Learning Store site that are about growing vegetables in containers. 

All of these are at our Learning Store site, and we do have our publications booth today so you can see some of these if you want to. Where you come in, where the Wisconsin Public Television booth is, our Extension booth is right behind that, and then right across the aisle is the Learning Store. So you can take a look at some of these publications if you'd like to. Okay, so now we're going to talk about the crop spacing that is recommended by the square foot gardening folks. They recommend that you plant in these one-foot grids, depending on the size of the plant, the mature size of the crop, that you plant either one, four, nine or even 16. Okay, so, that can be all well and good, but there are some little things called plant diseases that can occur. There are some plants that don't like to be planted that close together. They tend to get fungal diseases like powdery mildew and things like that. So, what we recommend is that you choose disease-resistant plants when you're using your square foot gardening grid. And you can also use smaller sized, again tomatoes, cucumbers, some of those other things. 

Or you may chose to grow you tomatoes in a large pot. One of the ways that you can figure out how to best do your spacing is either you can buy the square foot gardening book, and they have a whole bunch of examples of how to space different crops, and you can also go on the internet and, for free, find some of these things. One of my favorite ones is at Gardener's Supply, and you can pick your crops and then drag them over to your bed. It has a little bed icon and you can figure out how to do your spacing depending on what you want to grow. And here's another one. That's pretty impressive looking, isn't it? You can see that the bigger crops, like cabbages that are going to get quite large, there's only one per grid; whereas, something that's going to be very small, like radishes or leaf lettuce, that you can put quite a few of them in a single square. So, that's just another, I'm not endorsing either one of these sites in particular. They're just there for examples. If you do a search on square foot gardening sample plans, you will get a whole plethora of them that you can look through. Okay, so, I mentioned there are a few problems with square foot gardening. 

One of them is that it's really hard to do crop rotation. Now, when we're growing crops in the ground, we have all kinds of microorganisms that are in the soil, and a lot of them are good microorganisms. Some of the, although, are not so good microorganisms. Some of those, for instance, that attack our tomatoes, I'm just going to use that as an example because tomatoes have problems with just about everything it seems like some years. There are septoria leaf spot, which can overwinter in the soil. You can have early blight that overwinters in the soil. Now, because we're using raised beds and we're not really growing in the soil, you can really eliminate a lot of those problems. However, if you continue to grow your tomatoes in the same raised bed, not even just moving it around to a different spot in your one raised bed, you can build up various pathogens in the soil. So, that's what crop rotation is about, and if you're an organic farmer, that's one of the main techniques that you use to keep your crops healthy is that you make sure that you don't grow plants from the same family in the same area every year. You, in fact, use a three- or four-year crop rotation. 

So, if you don't know what plants are in what families, that can be kind of tough. I should tell you that we do, in the Extension booth, have a fact sheet on crop rotation that you can take a look at. It tells you what plants are in what families, and so that can help you. So, usually, again, a four-year rotation is what's recommended So if you had, like, three beds, you'd be perfect because you could do a three-year rotation, never growing your tomatoes in the same bed in any one year. So you start one bed number one, then move them next year to bed number two, bed number three, then back to bed number one. Now, you're also going to be adding new compost, new potting soil every year, so that will also help with this. There's the link if you want to go online to find our crop rotation fact sheet if you don't make it over to the booth today. You can look at that. So, again, if you only have one square foot garden, it's really hard to do crop rotation effectively because you're going to end up almost certainly with some plant that's in the same family and allowing those diseases to build up in the soil. So, again, using the, sorry, let me go back here a second. 

So, using plants that are resistant to disease, that's going to help you. Making sure that you're using good soil in your beds, that's going to help you. And crop rotation, that will help you too. Here's, also, if you can read it when you print this thing out, this gives you some idea also of which plants are in which families. So, for example, in the carrot family, APACA, we have not only carrots but also dill and celery and parsnip and cilantro and some other things. If you're looking at the tomato family, that also includes potatoes and eggplants and so on. So, you wouldn't grow any plants from any particular family in the same bed in a consecutive year. All right, mulching is going to help you out too. And one reason for that, particularly with things like tomatoes where you have soil-born diseases, if you put a mulch layer between the soil and the plant, the spores can't get from the soil up on to the plant. One of the ways that early blight is spread, one of the most common ways and also septoria leaf spot is that rain or your irrigation water hits the soil, splashes up on the plant leaf, and then sure enough then you start getting leaf spots. 

So if you have that mulch layer there, whether you're using straw or whether you're using hay or newspaper, any of that will help provide that barrier. Some people also will snip off the bottom few leaves of their tomato plant to, again, help prevent that spore transfer from the ground. Okay, now, square foot gardens, being raised beds, are going to be a little bit different than taking care of a regular vegetable garden that's in the ground. For in-ground gardens, I usually, or Extension usually recommends about an inch of water a week. Now, last year, because we had such high temperatures, it really was better if you put in two inches of water a week, and probably about two inches of water a week is what you're going to need in a raised bed. And you may even need more than that as the season goes on. Early in the season you've got cooler temperatures, the root systems are smaller, but as you go through the season, the plant gets bigger, the root system gets bigger, and the temperature goes up, which means that the soil, which is raised, and you've got the sun shining against the boards, that's all going to heat up which means the plants are going to lose more water and use more water. You're going to have the soil losing water to the air as it evaporates, and also you're going to have a bigger root system, bigger plant. Mulch will help there, but just make sure that your plants don't dry out. Okay, now I'm going to go into a few non-square foot gardens that are raised beds with a little twist on them. 

If you have kids, this is a really fun raised garden to use, and it's pretty cheap. You just go out and you buy yourself one of those goofy looking little six-foot kiddie pools that have the little fish and stuff swimming on them, and you poke some holes in the bottom. Usually I recommend you use one of the drills that has the rotary on it so you can make like a two-inch hole. Punch in about 10 of those, and then you can get some cheap wood slats. Again, you use the potting soil, and voila, you have a pizza garden. And in each slice, you can plant something that you might want on your pizza, like tomatoes, peppers, you know, onions, etc. The drainage holes are absolutely critical, of course, unless you want your plants swimming in the swimming pool. Other types of container gardens that are not on a square foot grid, you can still fit quite a few plants in something like a stock tank. And you can also certainly grid off a stock tank if you so desired. Again, you do need to poke holes in the bottom of that. 

The one issue, well, one of the issues that we have again, as I mentioned, when you have plants crowded close together, I'm sure that our plant disease expert, Dr. Brian Hudelson, would probably have a fit about this because he is always saying make sure you have good air circulation so you don't get powdery mildew and you don't get all these other fungal diseases. So that is one thing that can happen with square foot gardening. Again, you try and plan so that you get good air circulation and you don't have bigger plants overshadowing smaller plants. Another thing with just using smaller pots is that you can move them around if you have to, of course. These are some recommendations if you decide to use containers instead of a raised bed or in addition to your raised bed. These are some container sizes that best fit the root systems of these particular plants. So, you can see that in a small pot a lot of the herbs will do just fine, but, obviously, a cucumber or a sunflower or a tomato is not going to do fine in an eight-inch pot. You need at least, well, even for a patio tomato I'd use at least a five-gallon pot, or a 10-gallon would be even better. Peppers will do fine in a two-gallon pot. So you just kind of have to look at what the mature size is. 

And if it is blowing over all the time, you'll know that you goofed. So, one thing sometimes people will do is stake the thing to the ground. I've seen that in a number of situations. Here we go, as an example. This one I think is, well, it's not staked into the deck, but some of those rods may be running through the crevices between the boards to keep them standing upright. So, again, for those bigger crops, bigger pots. Yes? >> What kind of soil do you use in those pots? It's so heavy. >> Yeah, I understand. The question is, what kind of soil? Again, you're going to be using a bagged potting soil, which is pretty light, but I would mix it with a little bit of compost or manure or something like that in a four to one ratio just so that you give it a little bit of bulk. Another thing that you can do, and I've bought these really cheap little rolling platforms. 

You can get a little round wooden thing with wheels on it that you can get at you average hardware store. And so I do use those to move pots around, and, fortunately, I can roll them out in the summer out of my garage and roll them right back in again in the fall. So, that really saves my back. Was there another question? >> Yes. When you're growing tomatoes in a container like that, do you need anything in the bottom, like pebbles or Styrofoam, to make sure the water runs out, or can you just fill it with potting soil? >> That's a really excellent question, and the answer is unfortunately not very clear but I'll give it a shot. What you should do is you should make holes in the bottom, of course, but you also should make, if it's a tall, deep pot, like a five-gallon bucket, you want to make some holes about three inches up from the bottom of the pot in the side, and that's to facilitate the drainage. You really don't need rocks. That's just going to make it harder for you to move. So, I would just, the idea is the same, that you're making sure that you get good drainage. Good question. 

In fact, I think later on I may have a picture of that. So we'll see in a minute. Again, you want to use, for container growing of vegetables you want to use compact or bush form. You can get that for squash, you can get it for cucumbers, tomatoes, etc. or if you're going to be trellising, you can stake your trellis into the ground and lean your pot up against it. That usually works pretty well too. I've certainly spent enough time pounding rebar into the ground to make sure that vegetable pots and other pots wouldn't blow over. Okay, yep, there it is. You can see that he's putting some holes in the side as well as in the bottom. And, again, the reason for that is that the water, sometimes early in the season before the roots have penetrated all the way to the bottom, it tends to kind of pool down there at the bottom, and you can end up with root rot issues. It's a good idea to put a couple of those a few inches up from the base. 

Now, vertical gardening has become very popular again as our yards get smaller. If you have a fence or even if you have an exterior wall that is close to your house that you don't mind putting a structure on, you may want to try some of these things. Again, I've included websites if you are interested in looking into those particular products. There's also plenty do-it-yourself sorts of things that you might want to try. I've seen some interesting patterns and colors. I've seen people use all kinds of containers and paint them. Here's a couple that are in the kind of way of landscape pictures. Shelley Ryan, I believe, did a video on one where she had sort of a tree that was in one of these types of containers that are on the, let's see, that's you right. Had to look at it. Those are just --. 

For things like that, you want to grow things that aren't going to get very tall, otherwise, of course, they're going to droop over. But that can be a fun way to do some things like leaf lettuce, if you wanted to do that. There's another one next to it where somebody has used simple rain gutter. Now, if you're going to use that, you need to make sure that it's really well supported and that you stop up the ends so that all your soil doesn't run out and that you use smaller sized plants. Again, that would be a good one for leaf lettuce or maybe for flowers or something but not for something large or viney. You can even, there are even indoor systems that you can use. These are a little bit more pricey, but you can look those up. They have their own internal drainage so they don't drip on your floor. And just kind of another nice way to do things. There are, if you look on the internet under vertical gardening, again, you'll come up with just tons of different systems that are available out there. 

Okay, now for fertilizing your container plants, I've kind of alluded to this a little bit, again they have limited root space. It's not like growing them in the ground where they can spread out in search of nutrients. And since your soil that you're using doesn't have a whole lot of nutrients in it, it's going to be critical that you provide that. So, again, you can either use organic or you can use the traditional synthetic types. If you want to use something like compost, just keep in mind that it typically is less concentrated than the traditional synthetic products so you may have to use more of it in order to get the same kind of effect. But you can water in fish emulsion. I should warn you it's a bit on the fragrant side, so if you're going to use that as your main fertilizer, you may not want the plants real close to the house or under the window where you have to be smelling what smells like dead fish all the time. You can also use compost tea. That will work quite nicely as well, and we do have several businesses in town that produce compost tea if you don't want to produce your own. And then, if we have a year like last year, once we get to 86 degrees, 90 degrees, plants start to shut down. 

They don't use a whole lot of fertilizer. So at that point you can cut back on you fertilizing. No point in putting it out there in the environment. No point in wasting your money. The plants just aren't going to be growing fast enough to use it. And yet more resources here. We have, at the Learning Store, a number of different publications on container gardening, raised bed gardening, container gardening fertilization, etc, etc. And if you're looking for just one on generally growing vegetables in the Midwest, there's a great publication that's out of the University of Illinois that's called Vegetable Gardening in the Midwest, and it has just about every kind of crop that you might want to grow. And so you might want to take a look at that. I believe it's something like $30. 

It's a nice book. And, of course, the Square Foot Gardening book by Mel Bartholomew. The new version is out and available on Amazon or any of those bookstore types of businesses. So, thank you for your attention, and I appreciate it. [APPLAUSE]