Compost for Soil Fertility

Let’s keep it Growing with Compost!!!

So you put in this monster garden. It’s brilliantly conceived and flawlessly installed with the sweat of your brow and whatever comes from hardworking brains. It all looks amazing, so what is all this talk about people using compost?

You and your whole family are eating great, delicious, healthy, rejuvenating fresh produce! You have been voted most likely to succeed at life by your HOA. (which is a pretty forward thinking homeowner’s association for allowing you to put in such a vast, avant garde garden in the first place). Your keen, homegrown-veggie-fueled wits let you easily win arguments on the internet concerning politics and tightly held moral beliefs. Everything is going great…until….

One morning, as you sip coffee admiring your spread, you think maybe, just maybe, your extravagant heirloom tomatoes were a little bit further along this same time last season. Then you think the same thing about your pickling cucumbers…hmmm…maybe it’s just your imagination…

Or maybe you didn’t listen to your garden coach about the importance of tending to the microbial life in your garden soil and regularly replacing the essential nutrients that your plants rely on to make you oh so happy and healthy with their bounty…all that bounty!

So, what do you do now?

Let’s talk COMPOST! 

I’m about to jump into some talk about making soils happy and healthy and how to keep them that way. If you need a refresher, jump back to the Soils unit and meet us back here.

Healthy garden soil is a big mash up of all kinds of critters, plants, and minerals. Some are bacterial, some fungal, some alive, some dead, and everything in between, some even mycorrhyzal. Okay, so the mycorrhyzal ones are all fungi, but I digress.

When your soil fertility gets low, you’ll notice symptoms like slow plant growth or increased problems with disease or pests. Even without a regular soil test, it’s always time to replenish the nutrients that your gardening removes.

The best way to make nutrient rich and biologically active humus (aka black gold) to restore your garden soil is a compost pile. A compost pile near your garden is a great place to reuse plant materials from your kitchen and garden.

Although composting is really an art, meaning there are as many nuanced approaches to compost as there are composting gardeners.

The Compost Basics: 

  1. Clear grass and other objects away from a shaded patch of ground one square meter (or one square yard) that you can water easily and that close enough to your garden to easily haul materials back and forth
  2. Pile your garden plant waste (stems, stalks, husks, end of season plant skeletons, etc.) and plant-based kitchen scraps in addition to other bulky plant materials (leaves, smaller tree branches, etc.)
  3. Layer dried brown materials, like fallen leaves or old pumpkin vines, in with wet/green materials, like rotten fruit scraps or potato peels, in a roughly 30 to 1 ratio. Thirty parts dried material to roughly one part green/wet.
  4. As you are layering, water the pile with a garden hose, rainwater is ideal but tap water will be fine, enough so that when you take a handful from the pile and squeeze it, it will only shed a few drops of water.
  5. Using a garden fork or shovel, turn the pile every two weeks or so and add more water if it is necessary to maintain the original moisture content.
  6. The materials in the pile will break down faster in hot climates and more slowly in cool climates, although the pile, if mixed well and kept moist, will make a lot of its own heat to aid the process.
  7. When the pile has shrunk to roughly 1/3 of the original size and you can no longer identify the materials that you put in the pile originally, i.e. leaves or scraps are now all little black fluffy bits, your compost will be ready for use.

Tips for Compost Health:

  1. If your compost starts to smell sour or like something dead, it has gone anaerobic. Sometimes, too much water keeps the biology inside from getting enough oxygen. The answer is usually to turn your pile without watering it. If the smell doesn’t immediately improve, and the pile is still wet or muddy, turning every day should help eventually.
  2. If you can’t use your compost immediately, it helps to cover it with a tarp, etc. Protection from the elements stops the breakdown and drying that reduce compost nutrient quality and biological life.
  3. Make multiple compost piles, one at a time. That way you can have one maturing while you are feeding/building another slowly with your day to day garden scraps.

Applying Compost to the Garden: 

Now that you have this abundant source of black gold, let’s dd it to your garden soils. Compost is added before you plant when you prepare the bed, or after you harvest. To do this, you mix it into the top three to six inches of the soil, then water it in. Watering in moves the nutrients and biology into the soil, protecting them from the harsh sun and dry soil surface.

Other approaches: 

If you follow my blog, you know that I am a big fan of composting in place, aka Sheet Mulching. So, if you’re ready to experiment with more ways to build healthy soil, then you’ll love this:

More Resources:

Coleman’s book New Organic Grower has some great theory and a guide to compost production.

For much more detail and great descriptions of the mystery of soils, try The Soul of Soil. For more on the science in soil, try Teaming with Microbes.

Both are great jumping off points into the reasons why we compost.

More Compost Recipes: