Feedback on Plastic Mulch

article image
PHOTO: PICSFIVE/FOTOLIA
Would you use the material this bag is made of as garden mulch?

How can Tom Doyle (“More Plastic Mulch!“)
improve the fertility and humus content of his soil year
after year if he leaves his plastic mulch in place for a 10
to 20 year period? Seems to me that he’s taking away from
the soil without putting anything back. That’s not
natural gardening, that’s robbery!

Give me good ol’ rotten hay and the leaves from a nearby
town any day.

Sally Goldblatt
Honeoye Falls, N. Y.

As a gardener, I have some serious reservations about black
plastic mulch, especially a permanent one. F.
P. Hughes talked about attempting to sterilize some ground
with plastic in order to make a nice lawn, and I’m afraid
it might be possible. Only I doubt that the mulch would
select out dandelions and plantain (eat them, no?). It’s
possible you just might wipe out whole subterranean
micro-populations. Soil health depends heavily on all the
tiny beasties that live in it, and we don’t know that those
near the surface are not harmed by being constantly in
total darkness with reduced air circulation. Light is
essential to many life processes; we can’t just assume that
it’s unimportant to soil life (there’s a really good
article on light as “nutrient” in the July, 1971 issue of
Prevention magazine; worth digging up if only for the
questions it raises).

Plastic doesn’t feed the soil, either, and it makes it hard
for the gardener to do so. Taking without returning equals
depletion (theft, rip-off) I would think, even if the first
years bring fantastic crops. The fact that this black
plastic “works” should by itself be no selling paint to
gardeners concerned about long-term soil health.
Hard pesticides “work.” So do chemical fertilizers.

I haven’t used plastic sheeting in my own garden (I may, in
a little corner, but I’m certainly not ready to turn
my lone acre over to it). I’m skeptical about the material
lasting 10 or 20 years in usable size. We put clear six mil
plastic on the side of a drafty house once, and it was
shredded to smitherines the second year. Wind got into pin
holes and worked on it until the plastic was finished. It ain’t cute hanging in the trees. More protected if
flat on the ground, granted, but 10 years? Seems
that one sharp-toed pooch on a spree could do enough damage
to make a strip of the stuff useless.

On the other hand, when you finally go to discard the
plastic, it resists. It won’t break down in cooperation
with nature, and burning it is a pretty poisonous prospect.

I hope we go easy with this new mulch, using it only in
times of special need (say drought, or for tomatoes in an
unusually cold season, etc.) till we’re clearer about the
consequences of its wholesale adoption. How do earthworms
dig the environment that black plastic mulch produces?
What’s the microbe count in similar soils before mulch,
after black plastic for one year, and 10 years? Any
deficiency symptoms in plants after five years, 10 years?
How does nature react after the plastic is removed? Do
things quickly and naturally “green up” or is there a long
recovery period, leaving the bare soil open to wind and
water erosion? Fish in ponds are killed by raising water
temperatures a few degrees. How about the effects of
raising soil temperatures slightly over long periods of
time?

We need to know if we have here a good earth-loving tool or
just another paving material.

Judy Patton
Emmett, Mich

I love MOTHER EARTH NEWS, but would like to take strong exception to
the articles on plastic mulch. Since plastic is absolutely
indestructible, the only excuse I can see for using it in
the garden is if you can get it from a source that was
otherwise going to throw it out. But buy it deliberately? A thousand times NO!

I’ve achieved excellent weed and Bermuda grass control with
several layers of magazines or newspapers, which cannot be
recycled through industry in my area. Layers of this
material allow moisture to penetrate and, after the first
few days, becomes packed down and won’t tear or blow away.
Furthermore, newspapers decay after awhile and add
nutrients to the soil, which plastics don’t (if you use
plastic, seems to me you’d have to plow in organic matter at the end of the growing season). The papers can be
covered with grass clippings, leaves, wood chips, etc. to
make them sightly.

The only advantage of plastic over other types of mulch to
be in raising the temperature of the soil (but I wonder if
in a desert climate like mine, the plastic would heat up
the soil and plants TOO much and fry them to death). I’ve
never tried it, but I understand that the use of flat rocks
will produce the same insulating effect.

I don’t think that we gardeners who like to call ourselves
organic should be buying such things as plastic to use in
our garden. We should be setting an example for others to
follow.

Katherine Boswell
Las Cruces, N.M.

About MOTHER EARTH NEWS’ articles on plastic mulch RETRACT,
RETRACT THEM.

I worked on a truck farm in Pennsylvania that used only
plastic mulch (six mil). True, it helps retard weed growth,
but it never, ever rots. And the business about 10 to 20
year use is pure crap. Plastic mulch only lasts a season,
unless you plant in the same slits the next year, and then
fertilizer has to be applied very carefully or it sits on
the plastic and runs off away from where the roots
are.

At the end of the season, what with the dead pumpkin vines and
a few frosts, it’s impossible to pull the stuff up and
dispose it in one piece. It cracks, and bits of plastic
stay in the earth. We ended up by burning it in the fall.

Laying the sheeting isn’t easy either, even with the kind
of rig we used: a tractor-pulled plastic laying machine
that digs furrows and then fills them in. Problem was that
in any wind at all, the plastic wouldn’t stay put.

As an alternative, I’d recommend straw or sawdust. Water can penetrate but weeds can’t. If weeds do appear,
they can be pulled and left lying in the garden as added
mulch.

Paul Converse

Why did MOTHER EARTH NEWS have articles on plastic mulch?
Plastic is the most unnatural thing ever. It never
decomposes and it creates pollution problems. I’m opposed
to plastic mulch.

Seth Morgan
Ardsley, N.Y.

Sorry to see such a spread on plastic mulches. While they
do have their positive aspects, they’re ecologically
expensive to manufacture and impossible to dispose of in
any sound way. There are reasonable alternatives:

1. Those who use wood for cooking and heating find
themselves with sheets of bark lying all over the wood
chopping area. A thick mulch of bark should have nearly the
same soil-warming properties as black poly, provide better
aeration and (slowly) add humus to the soil.

2. Old newssheet is a fair mulch, if layered thickly, and
will eventually break down into humus.

Both materials will add acidity to the soil but this can
counteracted with wood ash. A light application goes a
long way.

I’m sure other readers know of good mulches that add
to the environment rather than foul it. Why not put that
information together in an article? But please, MOTHER EARTH NEWS,
plastics should be avoided as much as possible.

J. D. Cuddy
Shevlin, Minn.

Re: “Plastic Mulch” and “More Plastic Mulch!” I’m very
interested in reading such accounts of other people’s
experiments and experiences, and I intend to do my own
experimenting with black poly in hopes of extending my
growing season, but I can’t imagine any other
advantage to be gained from using it rather than a deep
organic mulch. The latter is far cheaper, decomposes
completely, adds much to the soil, retains water, and
is at least somewhat more appealing to the senses. I’ve
successfully “sterilized” an area in several different ways
(cardboard, shredded leaves, newspaper) without spending a
cent, and my mulch replenished the soil.

By the way, at the prices quoted it would cost me $67.50
for enough 1 1/2 mil plastic and $140 for enough six mil to
cover a vegetable garden that only provides for four
adults, one child and, occasionally, a few friends.

I reckon that if one had very little space and only enough
time to “plant seeds or seedlings in already made holes and
reap the abundant crop that gets bigger and better each
year”, plastic mulch might be suitable. As for me, I need
more evidence before I’ll consider investing a large chunk
of my time and garden — not to mention my money — in plastic mulch

Michael L. Marty
Demon, Texas

One of the basic premises of organic gardening is not only
to harvest a plentiful yield with few weeds, but also to
produce fruits and vegetables that are as nutritionally
valuable as possible This can only be accomplished by
replenishing the soil before, during, or after every growing
season. I read of no such provision in either article on
plastic mulch.

Every crop depletes the soil of certain ingredients and
after a period of years land can get “all worn out,” so to
speak. Nutrients must be returned to the soil in the form
of organic mulch, compost, or green manure so that plants
can absorb needed nutrients and return them to us.

For my part, I’ll continue to keep my soil healthy so that
it may keep me healthy.

Lil Woods
San Diego, Calif


Well, gang, as you’ll recall, we said that “we’re
still not convinced it’s a good idea but there’s definitely
a growing trend (among some otherwise conservative organic
gardeners, too) to plastic mulch”. Quite frankly, nobody
around here likes the idea either but (1) we’ve already run
article after article on natural mulches, (2) it’s our job
to report on and bring to your attention alternatives
of all kinds and (3) plastic mulches do seem to
work — at least in the short run — for people like
F. P. Hughes and Tom Doyle.

Whether the infernal plastic proves out over the long term
or not (and we rather doubt it) remains to be seen, but it is the mark of a rational adult to at least
consider an alien idea. Perhaps if a few more of us set up
test plots where natural versus plastic mulch can be
compared side-by-side over a ten year period, we’ll do away
with plastic in the garden once and for all … or get a
pleasant surprise when the godawful stuff surprises us with
desirable results. Either way, and with no malice
aforethought, we have learned something.

For our part, we’d say that gardeners who want to blanket
their vegetable patches with a single sheet of something
would be better off to “Carpet Their Gardens” with an old
rug of natural fibres as suggested by John Krill in “Use Carpet as Garden Mulch.” — The Editors.