Compost extract: Liberation versus libertinage
January 20, 2022
Last year, I wrote in these pages about making compost tea. This water extraction of compost, combined with foods to fuel the procreation of its beneficial organisms, is but one way to make the most of your microbiologically complete compost; it's the bacchanalia of compost infusions.
Tea season is spring and summer. By then, I will have refined my process greatly and plan to share the photos of my new invisible (to the naked eye) friends.
For now, I could make a batch of 21-24 day compost, if I formulate, hydrate and turn it correctly as discussed
earlier. Lately, I've been collecting and freezing the correct proportions of perishable materials in 25-pound pet food bags in a chest freezer.
Then I could make an extract of the compost, which is incredibly easy, fast and beneficial. If I make too much compost to use immediately, I can age it up to six months - it will only become more diverse and dense in soil life.
Compost extract liberates bacteria, fungi, protozoa and nematodes from compost and serves as a rapid-delivery system to the plant. It washes microorganisms into the root zone to do their work, whereas surface application encourages them to glue and secure themselves aboveground.
Unlike compost tea, it is only used as a soil drench. Compost tea, I have learned, is only properly used on aerial parts of a plant, unless it is being applied directly to a root crown for crown rot.
As such, compost extract requires no fancy sprayers, just like it needs no complex brewers to occasion liberation and libertinage; you can massage the microorganisms out of compost in a bag and apply them when you have an appropriate concentration to meet your aims. Depending on the quality of the compost, you might need to change it a couple of times for peak saturation of beneficials.
Here are some best practices with your composting: correct materials in functional proportions, optimal moisture level, aeration and turning, can get you a long way towards compost suitable for extraction. Only a microscope can immediately confirm that you've reached your objectives, or that the compost you've bought can deliver the goods - but more on that later.
For now I'm going to take my procedurally correct compost and put it in a plastic mesh bag with 400-micrometer pores. The pore size is important because the bag should retain the particulates, but allow the largest fungal hyphae segments and wormlike nematodes to pass through (if they don't approach the pore sideways). The closure of the bag is usually hook-and-loop or a zipper, or you might fold it over a couple of times and clip it.
Fill a 5-gallon bucket three-fourths full of water. If your water is chlorinated, add humic acid just until the water turns from clear to brown-tinged. This is to neutralize the chlorine that would otherwise kill your microorganisms.
Wash your hands and put 1-2 pounds of compost in the mesh bag. Give it a couple of dunks in the bucket; you should see some brown- or honey-colored liquids leach out. These are humic and fulvic acids, which show the presence of beneficial fungi in the compost.
Shake the compost to one corner of the bag, submerge it again and knead it underwater for 30-60 seconds. Don't use a scrubbing motion, but instead something between tickling and using baoding balls (Chinese hand-exercise balls often made of metal and rotated in the palm of the hand). You're trying to massage out the microorganisms without injuring them.
Lift the bag out, shake the compost to the opposite corner, and repeat. Once you've tumbled and kneaded the compost through all four corners, you're done. Return the spent compost to the compost pile to be repopulated with critters.
If kept cool, the extract can be applied within several hours. Longer storage is possible, especially if aerated, but the extract will lose diversity over time.
I plan to assay local composts by microscope and offer the results, so you know what you're getting if you're buying it. It will be clear that not all composts are created equal.
Alex Féthière has lived on Harstine Island long enough to forget New York City, where he built community gardens and double-dug his suburban sod into a victory garden. He can be reached at [email protected]