Surface composting is not very esthetic, but it works! Photo: http://www.lesjardinsduclosjoli.fr
In this day of dedicated compost bins and carefully planned layers of brown and green materials, surface composting almost comes across as something radical and innovative. Yet, it’s the oldest form of composting, the ones our farming ancestors used, and it’s so simple to carry out.
The technique couldn’t be easier: just toss your decomposable waste into the garden, around the plants that grow there. No need to bury it (although you can do that too, but then it becomes trench composting): just let it rot (the less polite term for decompose) where it falls. And as it decomposes, it feeds the soil in minerals and the soil will in turn feed your garden plants. Yep, just like regular composting, but with fewer steps.
In the ancestral form of surface composting, farmers harvested plants, cut off the edible parts to bring back to the family, and just tossed the residues back onto the ground. The residues would then decompose and feed the soil for next year’s crop.
In the modern version, surface composting is mostly used for vegetable and kitchen scraps as well as weeds. Not living perennial weed roots (more on how to handle those below) or weeds with seeds that could root or sprout and cause problems, but annual ones nowhere near maturity. Or leaves of perennial weeds. Spread the scraps fairly thinly, no more than an inch or two (2 à 5 cm): too thick and there might be some smell.
When Mulching Equals Surface Composting
You may already be surface composting without knowing it. When you spread straw, chopped fall leaves or shredded tree residues that have gone through a chipper shredder (this is officially knowing as ramial chipped wood) over the garden as a mulch, it’s actually a more sophisticated and attractive form of surface composting. After all, such mulches do decompose over time and you do have to keep topping them up with fresh material. And, of course, they enrich the soil just as compost does. So, mulching with decomposable products therefore is a form of surface composting.
Esthetics Be Damned!
Basic surface composting with vegetable scraps and weed bits is not a technique for prissy gardeners who want perfectly manicured gardens. After all, you’ll see kitchen scraps sitting out in full view, bright orange carrot peels, moldy vegetables, etc. It’s likely you’ll mostly be doing surface composting in the vegetable garden, though, and who really cares what the ground between vegetables looks like? Or do it in the farther corners of your flower garden where it won’t be noticeable.
Some gardeners remove their mulch, put down the scraps, and cover them with mulch again. That solves the esthetics problem, but it’s also extra work. I just toss the materials on top of the mulch and let Mother Nature take care of it. Earthworms come out at night and pull bits of material down under the mulch. If you’re patient, you can actually watch them do it. Fascinating!
Killing Roots and Rhizomes First
You don’t want to drop living roots and rhizomes of invasive perennial weeds onto bare ground. If you do, they’ll soon reroot and start a new invasion. So, dry them out first, laying them in the full sun until they’re thoroughly dead. This will take a few days (even longer in rainy weather), but exposition to the air and solar radiation will kill even the most persistent roots. I just hang this kind of weed on the branches of trees and shrubs or the foliage of tall perennials or vegetables. By the time they’re so light the wind knocks them to the ground, they’re dead and ready to decompose. And I just let them decompose where they fall.
What About Varmints?
I’ve been surface composting since I was a child and have never had a problem with rats, skunks, groundhogs or other mammalian pests rummaging through the surface compost. (Nor have any of the above ever visited my actual compost bin.) Sometimes I see birds pecking through the refuse, probably going after fruit flies and other insects, but mostly, I just see earthworms and even then, only when I go out at night. They seem to love surface compost.
Annoyingly, groundhogs go right past my decomposing scraps to dine on my still-living vegetables. I guess fresh vegetables are just tastier!
Surface Composting Dos and Don’ts
- Do add anything from the vegetable garden you won’t be eating, just dropping it to the ground between the plants: carrot leaves, insect-damaged leaves, rotten or damaged fruits, tomato and bean stems at the end of the season, etc.
- Don’t add anything tough that won’t decompose readily, like woody branches and corn cobs;
- Don’t add dairy, eggs, meat or bones might attract rats and other animals;
- Do chop up kitchen scraps finely for fast decomposition (I run them through the blender);
- Don’t drop diseased plants and leaves in spots where you’ll be growing the same vegetables the following year (put them elsewhere);
- Do add lawn clippings (if you don’t grasscycle);
- Don’t add seed heads or flowers from weedy plants: they might self-sow.
Surface composting: I suspect most gardeners already do it to a certain degree, but now you have a name for it.