Compost for Your New Veggie Garden

Wow, we finally hit Day 10 of Garden Tribe’s Vegetable Garden Boot Camp. Yay! Subject of today’s post–COMPOST.

It almost doesn’t matter where you’re getting your information, it’s likely you’ll find this is one of the top recommendations for any garden, vegetable or otherwise: Use Compost! As I said in the post on Understanding Soil, “Feed the soil and the soil will feed the plants.” (That’s not exactly what I said, but who’s noticing?) And compost is soil food. The micro and macro-organisms that live in the soil subsist on what the rest of us throw out–at least the organic stuff we throw out. When the bacteria, fungi, mycorrhizae, pillbugs, earthworms, beetles (I could go on… and on…) feed themselves on the apple cores and tea bags, and garden debris, they cause decomposition over time. Which, when added to soil, continually foster a symbiotic relationship/activity with plant roots, allowing the roots to take up nutrients that would otherwise be unavailable to them.

Compost also makes the environment more conducive to the presence and proliferation of all these beneficial community members, by permitting better aeration and better water retention. The compost actually improve the structure of the soil by allowing the soil particles (fine to coarse), along with the organic matter and the bacteria/fungi to clump together (aggregate) into larger, combination particles. I know that’s an awkward sentence, so just imagine the clay soil we read about yesterday (fine particles) retains its nutrient value, but also loosens up and permits better root expansion. The sandy soil (coarse particles) stays light with great drainage, but gains better nutrient and water retention value. Everybody’s happy!

And since compost was once plant material, the nutrients and trace elements that went into the content of that plant material is now present in the compost. This includes not just “the big 3” NPK (Nitrogen, Phosphorus, Potassium), but Boron, Manganese, Molybdenum, Zinc, etc– elements we’ve hardly heard of, never mind remember they’re needed for plants to grow. Compost doesn’t have the amounts of these nutrients that you’d find in fertilizers, but because you’re using compost for more reasons than just fertilizing, you are using a much greater volume of material, so you still end up with an appropriate amount of most-maybe all- nutrients, and get lots more benefits besides.

How To…?

So how do you make compost? All organic matter eventually decomposes. What you’re after is relatively rapid, controlled decomposition. The process is dependent on fuel and heat–just like a fire. The fuel is “green” material, or mainly nitrogen containing debris, and the heat is “brown”, or mainly carbon containing debris. The “green” can be any of your food scraps (preferably no grain products, and never any meat products, so that vermin will not consider your compost bin their local restaurant), and any garden material (except invasives or weed seeds, and probably not woody garden refuse–takes too long to break down). The “brown” can be fallen leaves, straw, shredded newspaper (inks and colours are vegetable-based products these days–happily). My usual practice is to wrap 2-3 cups of kitchen scraps in 2-3 sheets of newspaper, and throw that onto the pile. In the fall I collect as many bags of fallen leaves (from neighbours or trees down the street) as I can, and then add them to the compost bin through the year. You need a lot more brown than green, but when you do, you’ll see how fast it all shrinks down and begins that lovely process producing “black gold”.

Important to the whole process is not letting pet micro-organisms die through lack of oxygen, or lack of water. Intermittently mixing the pile of material, layering greens and browns, and making sure there’s at least 3-4 times as much brown as green will keep it oxygen-rich. And locating the compost where it will receive enough rain, and turning the hose on the compost pile during dry spells will keep it moist enough (optimal moisture content described as a “wrung out sponge”– I’ve never tested my compost with bare hands to know that I’ve got the “right” moisture.).

If you want to research this a little more, University of Illinois has a great little e-booklet called Composting for the homeowner that you might like to look at.