In my experience, mulching is the single most important factor in
organic food-growing success. Mulch builds your soil fertility, suppresses
weeds, prevents winter soil heaving, and helps regulate your soil moisture and temperature—it’s
the magic pill for your garden!
I go into detail about mulching in my free ebook, Little Farm in the
Garden. So for this post, I’ll just share a few ideas I’ve had lately about
the mulching process—the quick and dirty version!
Do #1: Ideally, I put my food-growing areas to bed for the winter by
covering the soil with chopped leaves (or leaves that have been decomposing for
a while, known as leaf mulch), then a layer of compost on top. I also use a lot
of dead brakenfern, because we literally have acres of it.
In any event, we have such a rainy climate that the leaf
matter and compost stays nice and moist all winter. Until it doesn’t.
A couple of weeks ago, after all the snow had melted, a late winter
Northeaster—very cold, dry air—roared through Berryridge Farm. I’d thought the
soaking rains we’d had just before this storm would keep the leaves wet enough
to stay put. But no. All the chopped leaves and my lightly-applied compost dried
out in no time flat.
Watching that high wind peel most of my mulch right off the beds, the
mulch I’d applied so conscientiously, I realized where I’d gone wrong.
I generally am not able to create enough compost for all my beds from
my kitchen compost pile —there are just two of us generating fruit and veggie
scraps for the raw material. Which leads me to:
Do #2: For fall mulching, unless you have enough compost to cover the
entire bed with at least two inches of it, you might try this instead. You can
still top the mulch with whatever compost you have available, but then cover
your mulched beds with lots of heavy vegetative material. You can use prunings,
bark, or even cardboard, if you weigh it down. But I’ve had plenty of cardboard
fly off my beds too!
If you’re thinking of re-mulching your beds for spring, you don’t necessarily
want a super thick mulch layer. Although it will retard weed growth, it will
also prevent your soil from warming up for seed germination.
What I’m trying is scuffing the top layer of soil a little, then
lightly incorporating a layer of chopped leaves. I’ll still put compost on top,
but this way, I don’t have to see an entire layer of leaf bits fly away in a
brisk breeze.
John has created a good sized pile of thick bark from a big old alder
he’s been processing for firewood. For my spring bed prep, I’m going use the bark on top of the mulch to
control weeds, then I’ll remove the bark maybe two or three weeks before
putting seeds in the ground to let the soil warm.
Do #3: Keep a supply of mulch for top-dressing your beds. Or at least
for those crops that require mulch for a decent harvest.
For example, when I plant garlic in November, I top with soil with a
very thick layer of chopped leaves and a LOT of compost. This is one crop I
thoroughly cover—after all, being underground for 3 ½ months before sprouting,
the seed garlic needs to be protected from weather before the little green
shoots appear.
Potatoes are another crop that needs lots of mulch. Without some kind
of top dressing, the spuds near the surface often get exposed to sunlight,
which turns the skins green. Those green spots are toxic, so keep those taters
covered!
Count blueberries as a third crop that definitely requires mulch. The roots
need to be kept very moist, but they are shallow—many of them barely below the
surface. So applying mulch will keep the roots happy. But…do not apply
composted chicken manure. Blueberries love acid soil, and any manure-based
mulch or compost is too alkaline.
Do #4: If you’re short on leaves and looking at options other than
home-grown mulch…In the last couple of food-growing seasons, I’ve covered my
veggie beds with cardboard. It’s generally because I haven’t kept the beds
weeded, and the weeds got so dense I had to apply a “killing mulch.” Cardboard
does indeed do the trick: cover an empty, weedy bed in fall and you’ve got
beautiful soil by spring.
The good news is, earthworms love it.
The bad news is, so do slugs. So anywhere you have moist cardboard, you’ll
be sure to be raising a good crop of baby slugs. The other downside is, after a
long winter, your cardboard will often be in tatters, and you’ll be picking up
those pieces of cardboard all over your yard all spring and summer.
It’s true, the cardboard will eventually break down in a couple of
years, but unless you have a spot out of sight for all that rotting cardboard,
it’s pretty unsightly. I have also used thick layers of newsprint as a killing mulch, but again, there's all that decomposing paper to deal with by spring.
On to “Don’ts”...
Don’t #1: It’s a small but important detail: Avoid using fruit tree
leaves or prunings for mulching. They generally contain a lot of funguses that
you don’t want to add to your soil.
Don’t #2: Well, it’s not exactly a Don’t, just a caveat: Use other killing
mulches with caution.
True Confessions: I have sometimes let my beds get so weedy I need
something stronger than cardboard: I have to “fry” those weeds—covering some
areas with scrap steel roof panels. In the summertime, the ground beneath gets
so hot the weeds just cook to death in a number of weeks.
The problem is, the soil “cooks” too—including all the beneficial
microbes and other goodies. I have noticed the crops where I’ve used steel panels
on the soil have never thrived. This year, I am rebuilding the soil in those
areas’ with more leaf mulch. I’ll still use the panels, but only on pathways.
Black plastic: it’s one of the most commonly used killing mulches. And
it sure does work! Once year we bought two large packages of black plastic
sheeting and used it all over the place. Our weed problem was solved.
But solving one problem often creates another. Being the thrifty
gardener that I am, over the next few years, I reused the plastic. Over time,
that plastic breaks down, and I subsequently spent many, many hours picking
bits of it out of the soil. My concern was, and is, that birds will think those
shiny little bits are yummy bugs and will eat it. So, I’m not longer a fan.
Little Farm in the Garden has an entire chapter about mulch and
compost—I hope you’ll take a look! You’ll find the free ebook at Amazon, the
Apple Store, Kobo and all other ebook retailers.
If you’re a food gardener, what are your mulching dos and don’ts?