The Washington Post - 19.09.2019

9

DC

the washington post

.

thursday, september

19

,

2019

growing veggies, and especially as they
start out as seedlings, it’s vital to keep
weeds at bay by pulling them and carefully
cultivating the soil regularly. When beds
are not being used, they need to be covered
or, better yet, sown with cover crops. This
is also true in the colder months as winter
annual weeds germinate in October and
develop into seeding monsters in March
and April.
Winter r ye, vetch and clovers, sown
now, are green manures that will crowd
out winter weeds.

Hoes and other weeding tools

The common or garden hoe is great for
breaking up and grading loose soil but not
so good for weeding. Some gardeners like
an oscillating or stirrup hoe to attack a
weedy bed, but I prefer a hoe with a thin,
razor-sharp blade for slicing quickly
through weeds in tight areas — that is,
close to desired plants. The Dutch hoe is
such a type, designed to be thrust forward
at or just below the soil surface. My choice
is a hoe you draw — I use a model with
interchangeable heads, using its
Interlocken Draw Hoe attachment ($16.99,
wolfgarten.us).
Johnny’s Selected Seeds sells a range of
sharp-edged hoes. Various Japanese-made
hoes have high-quality stainless steel
blades and seem readily available online.
The weeding knife doubles as a trowel
but is useful for light cultivation of soil and

slicing of weeds young and old. One side

has a serrated edge. The Japanese version

is called hori-hori ($21.99, gemplers.com).

I wouldn’t be without it.

For fine weeding — around emerging

lettuce seedlings, for example — I use a

pocket knife that I keep sharp on a

whetstone.

For tap-rooted perennial weeds such as

dandelions, use a fish tail weeder to

remove the entire plant.

Solarization

For whole areas being cleared of

established weeds, you can use a plastic

sheet to trap the sun’s rays and cook the

weeds beneath. Solarization works only on

sunny sites during the hottest months.

Experts say clear plastic is more effective

than black sheeting. First, soak the

ground. Some solarizers like to elevate the

plastic a little — bricks will work — to form

an air pocket to cook the weed seeds and

seedlings induced into growth by the light,

heat and water. The plastic must be secure

at the edges against high winds and rips

promptly patched.

Sonja Birthisel, a postdoctoral scholar

of weed ecology at the University of Maine,

says that two weeks should be long enough

to kill most annual weeds but that

perennial weeds such as yellow nutsedge

may take as long as 12 weeks. Caveats:

You’re using environmentally unfriendly

plastic, it is not instant, and it’s ugly. It can

also harm soil microbes, but they will

come back, Birthisel said.

Don’t confuse solarization with

landscape or weed-blocking fabric, which

is typically laid in strips, pinned to the

ground and covered in mulch. Shrubs and

perennials can be planted through the

fabric. I am not a fan of fabric; it prevents

you from planting afresh — bulbs, for

example — and it invariably becomes

visible and looks ugly, among other issues.

Flame weeders

If you have large areas of patio, paths or

driveways, flame weeders are a way to deal

with those pesky weeds that grow up

between the cracks and defy hand pulling.

Most models are commercial-grade, rely

on barbecue-type propane tanks and are

pricey. Horticulturist Roger Davis operates

one named the Weed Dragon at L ongwood

Gardens in Kennett Square, Pa.

“It’s perfect for gravel patios, brick paths

and patios, slate pavers,” he said. “You

would never want to use it in a mulched

ring under shrubs or trees.”

Established perennial weeds may come

back after a few weeks.

These weeders may be restricted for

obvious reasons in areas of the country

prone to wild fires. Save the flip-flops for

the beach.

“We don’t let just anyone use it,” Davis

said. “You have to have a bit of training

here on site.”

Organic herbicides

Vinegar- or acetic acid-based sprays will

kill or damage top growth, but

formulations that are concentrated

enough to be effective herbicides may also

be acidic enough to injure the user. T hey

are useful on emerging weed seedlings.

Herbicidal soaps are available and work

by using salts to break down the cell walls

of targeted plants.

Corn gluten products work as a pre-

emergent herbicide; they will kill only

weeds beginning to germinate, not

established ones. They are expensive,

especially if used in quantities required for

a lawn, and must be applied at the right

time to be effective.

They are sold for use, too, in vegetable

gardens, but then you can’t re-seed treated

areas for several weeks afterward.

I can’t imagine tying my hands in such a

way in the vegetable garden. It’s a place

where I’m constantly reworking beds,

harvesting, pulling failures and re-seeding.

And weeding.

[email protected]

@adrian_higgins on Twitter

 Chat Thursday at noon Higgins will answer

questions about herbicides, weeds and all

things gardening. Submit questions at

live.washingtonpost.com.

 Also at washingtonpost.com Read past

columns by Higgins at

washingtonpost.com/home.

ISTOCK

Weeds fill empty spaces and germinate in disturbed soil, as buried weed seeds find light and moisture. The most effective and sustainable way to control weeds is to crowd

them out with desirable plants, not oceans of mulch. In the lawn, the answer is vigorous turfgrass; in ornamental beds, it’s intensive plantings.

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