All right, folks! I know you're all anxious for the next step in your special gardening experience. Well, here goes! Having made your box, we need to put soil in it. But not just any soil will do. Many soils around the country are not satisfactory for raising healthy vegetables (I never understood this while living in Indiana). There are many ways to improve your existing soil, but we won't even give any space to that at the moment. We're going to start out with great soil instead of working towards great soil. Surveys show that it usually takes about seven years to get your soil the way you want it if you practice general soil improvement, and that involves adding lots of manure or compost, and sometimes things like vermiculite or perlite, plus calcium and other minerals. And guess what the average American does after seven years? They move! And the odds are that the people moving in behind you don't garden. Just think of all that hard work and money invested, now being idle, or worse yet, forever sealed by a building project or maybe a parking lot! That's why I recommend putting some kind of barrier between your raised beds and the existing soil. It makes it easier to take the soil with you if you ever decide to move. Or you could even sell it, if for some strange reason you don't want to garden anymore. It is after all a better growing medium than the potting soil you buy in the store!
Obviously, having perfect soil in your entire garden might be too cost restrictive to try to do it all at once. But remember, one 4-foot by 4-foot bed will grow the same amount of vegetables as an area four times that size in a regular garden. And with this special soil mix you don't need to do a soil test! We already know it's just right for vegetables.
What You Need
In his book, Mel Bartholomew recommends using equal parts of vermiculite, peat moss, and compost. All three of these ingredients are natural. The mix is a pleasure to work with, has a light fluffy texture, and smells good. The first two ingredients have no nutrients; they are sterile. Compost, however, is loaded with all the nutrients and minerals that you could imagine. If you think making your own garden soil is too unusual or too extreme, ask yourself this: "What do professional greenhouse growers use for growing crops in their greenhouses? Do they go out and dig up the fields for soil?" Of course not! They mix up their own potting soil from carefully selected ingredients and never use outside soil. We will use the same concept, but let me say again: start in small. Don't think you have to convert your whole garden to square foot gardens in one year. You
don't have to do it all at once.
Using a five-gallon bucket, I discovered that three buckets full was just right to fill a 2-foot by 2-foot box made out of 2x6s. This made it very simple, since I needed equal parts of three different ingredients to make the mix. Multiply that times four to fill a 4x4 box. I mixed it together in a big wheelbarrow with a hoe (three buckets was all I had room to mix in the wheelbarrow at a time). You can also dump the ingredients on a tarp and mix it by tumbling it from side to side. However you do it, be careful not to waste any. This is too precious to allow a lot of waste. If it's too dusty, you can spray it down with water, although I prefer to just do it when there's not much wind rather than soaking it before it's in the box.
Now, for those of you who live in the south where heat and drought are common, I'm going to recommend a slight change from the original Mel's Mix. Mel was trying to make it very simple by saying to use equal parts of everything. Also, he was concerned about over-watering. His mix is so light it is impossible to over-water! The soil will soak up what it can (which is a lot) and the excess will drain right out. Here in central Arkansas, I found that Mel's Mix dries out
too fast during hot weather. So I made a few changes which are actually helpful in more than one way. I cut back on the vermiculite (which saves money, since that is the most expensive part of the mix around here). And I made up the difference with compost (which saves money again, because compost is free around here). And this gives the mix more bulk and holds the water a little better. This could be the wrong thing to do in cool or damp parts of the world, but it works great around here. I've never had anything suffer from over-watering yet!
Vermiculite
Vermiculite comes from mica rock, which is mined out of the earth, ground into small particles, and heated until it explodes like popcorn. This makes a sponge-like "puff" which makes your soil extremely loose and serves to soak up water and hold it until your plants need it. Vermiculite comes in different grades - fine, medium, and coarse. The coarse agricultural grade holds the most water and also does the most to keep your soil loose, which is important for root development. Call around to your local nurseries, garden supply centers, greenhouse supplies, and major home improvement stores, and even farm feed stores and ask if they have large 4-cubic-foot bags of coarse vermiculite. If you happen to live in an area where it isn't sold locally, try the internet. For my local friends, I've already done the research. It is available on the internet, but I haven't found a cheaper source than our local stores, especially once you consider shipping. The cheapest place I know of is E&R Seed in eastern Indiana, where they sell it for about $15.00 a bag. To have it shipped here, however, more than eats up all the savings. They don't have a website, because it is Amish owned and operated. It is available at our local 270 Feed and Farm Store for about $23.00 for a 4-cubic-foot bag. Breshear's Nursery has it here at the Highway 5 and 7 Junction between Hot Springs and Hot Springs Village. They charge about $25.00 a bag. Lowe's has vermiculite in 8-quart bags, but the problem is that it's the finer grade and prohibitively expensive. Last year the general manager of our local Lowe's store, who is a personal friend of mine, sold a bunch of his vermiculite to me at a very special price after spring planting was about over, and I told him I would buy it in quantity to save him the warehouse space required to store it. I figured if he could match the price per cubic foot to that of the bigger bags, I'd find a use for it or be able to re-sell it after my gardening class. So I've been using some of it along with the coarse kind in my raised beds, with satisfactory results.
Using Mel's method, one 4-cubic-foot bag of coarse vermiculite is a little bit more than you need for one 4x4 raised bed. Four cubic feet fills a five gallon bucket five times. With my modifications a 4-cubic-foot bag will be enough for two 4x4 beds. If you are making a 2x2 bed like I am showing the children how to make, all you need is three gallons. I figured my local gardening friends might not want to buy a big bag of it for such a small garden, so I am offering it for sale in 3-gallon increments, at $3.00 a piece. I also still have 8-quart bags from Lowe's which I can sell for $2.50 a bag.
Some people always ask if they can use perlite instead of vermiculite, because it is cheaper. The answer is NO. What is the difference between the two? Perlite is good only for drainage; it has no water holding capabilities at all.
Peat Moss
This also is a natural product that comes from bogs and marshes. It acts like a sponge and will absorb tremendous amounts of water. It helps to keep your soil loose and light. The most economical way to get it is in the compressed bales. 270 Feed & Farm has it for about $19.00 for a 3.8-cubic-foot bale. Breshear's Nursery is asking $15.00 for the same size bale.
Lowe's has them a little bit smaller, a 3-cubic-foot bale for $10.00. Per cubic foot, those at Lowe's are cheaper by a narrow margin.
As you take it out of the bales and loosen it up, it will expand quite a bit. A 3.8-cubic-foot bale will fill a five-gallon bucket approximately nine times. There is more variation here than with the vermiculite because of all the compression and expansion involved. You need one bucket for a 2x2 bed, four buckets for a 4x4. One bale will be enough for two 4x4 beds, with a little left over. You can either divide what you have left over between the two beds or save it for some more beds in the future. Or perhaps mix a small batch of the special soil for a container-grown plant. The smaller bales from Lowe's will give you about seven buckets full. If you want to skimp, you can just divide that between two 4x4 beds and make up the difference with compost. Once again, for those who are local here and only need a little bit, I can sell you smaller portions. A 5-gallon bucket full, just enough for a 2x2 bed, costs $2.00.
Compost
Around here, the cheapest and most readily available of these ingredients is compost, because the city of Hot Springs has a program where they dispose of brush, yard waste, leaves, tree trimmings and similar materials with a
large composting operation. It is possible to buy compost from greenhouses, nurseries, and home improvement centers, and sometimes farm stores, but this can be very expensive. Mel stresses the need to use a
blended compost, meaning if you do buy it bagged you need to buy 5 or 6 different kinds of compost and mix them together. This is the only way to ensure that you get the full spectrum of nutrients that your plants need, because most commercial composts are made from only one material, which is usually not nutritionally balanced if left by itself. The compost from our local composting facility already has a variety of materials in it, so it qualifies as a blended compost. Visit this
link for more information on their hours of operation. There have been a few times during the spring that their supply of compost ran out due to high demand, so if you want you can call the number on their website before you go to make sure they have some. You may load all you want for free, but you can pay them to load it for you on certain days if you choose to do so. For $6.00, they will load your pickup, and do it in a matter of seconds. One 5-gallon bucket full is what you need for a 2x2 bed. However, compost is the one ingredient in this mix that you will need to add more to at least twice a year, so I suggest you get more and store it somewhere free of weeds. Storing it outside is all right; but in a garage or shed is better. Store it in a garbage bag or extra trash can or similar sturdy container.
One drawback about this compost is that it does have some weed seeds in it. The reason for this is that their composting process is not hot enough to kill all the undesirable seeds and stuff in the materials that are brought in. The best thing you could do is make your own compost, and make it hot. The easiest way to do this is with some kind of a compost tumbler. Maybe we'll write an article about composting later. In the meantime, my opinion is that free compost with weed seeds is better than not having compost, and even better than paying five to ten dollars per cubic foot for compost.
The cost of the soil for a 2x2 raised bed? Five dollars. The total cost so far for making a 2x2 bed with 2x6s (with the soil in it) is about $10.00. Start-up cost for a 4x4 bed is about $30.00. You never have to add more vermiculite or peat moss. All you ever have to do in the future is add more compost. Every time you want to take one crop out and plant something else, add some more compost. How is this possible? Because if you have a living soil, full of microbes and healthy bacteria, they are constantly "digesting" the soil, breaking it down and releasing nutrients to your plants. Using compost is gardening God's way!
Blessings to all!
