Hi, I am Ed Bruske from D.C. Urban Gardeners here in my garden in the District of Columbia talking to you about compost, and what you just saw me doing there is planting a cherry tomato plant. It's a little late in the season, but this cherry will grow really fast and be producing tomatoes all the way into October - and what I have done is, to help the tomato along, when I dug the hole, I filled the bottom of the hole with compost, and now I surrounded the top of the tomato with compost and just scratched it into the surface a little bit. You may be wondering, What is this compost doing for the soil and for the plant anyway? I guess we need to go back a couple of steps, because compost really is the organic portion of the soil; that means the part of the soil that came from things that were once alive and that have been broken down in the decomposition process by bacteria and fungi and all kinds of little critters. It happens all the time in nature, and a good healthy soil really needs at least 5% organic matter in it to support good, healthy, plant life. All those micro organisms really work together with the plant, around the plant root zone. We call that the soil food web and they are bringing nutrients to the plant, the plant is feeding them, and the compost in the soil does a number of other things as well. In fact it does so many good things for your soil; I would hardly have time to mention them all.

But a couple of really important things are that, one, it holds water. Compost or the organic matter in the soil will hold its own weight in water; so if you want to get water down to your plant roots and hold it there, you want to have organic matter or compost in your soil to do that. Another thing that compost does, is it helps make nutrients in the soil, things like, nitrogen, and phosphate, potassium, and a number of minerals that are essential for the plants that are already in the soil. The compost interacts with those and helps make them available for the plants to take up through their roots. So, organic matter is really important that way. Other things it does is, it helps hold oxygen in the soil. If you have ever seen a soil that was really poor, did not have much organic matter in it, it would be really hard, maybe hard as a rock; but you put compost in there, and it loosens it up, it gives the soil what we call great tilth, this crumbliness that happens in the soil. And what that is, is all the oxygen is in there, the space between all the particles in the soil, and the plants roots need that in order to take up oxygen through their roots. So those are some of the great things that compost does; it's not really a fertilizer, it has a low nitrogen component to it, it's not like chicken manure or anything like that, but it does do all those other great things for the soil and it also adds nutrients. Next, we are going to be talking about other kinds of compost bins, the manufactured bins you can buy for your garden, and it might be particularly useful for you if you live in an urban setting.