Yard
and Garden
August
22, 2015
Q. I am having a hard time controlling weeds in my
garden. I do not like to use weed killers in the garden, so I pull the
weeds by hand, but they just break off and come back within a few days.
Is there some way to get rid of the weeds without weed killer?
A. When soil is dry it may hold plant roots tightly causing
the weed to break off and then regrow as you have described. Weeds are
much more easily removed from moist to even soggy soil immediately after
irrigating. For some weeds this is effective even when the weeds are very
close to the desirable plants. Some weeds have a more fibrous root system
and may pull us much soil at the base of desirable plants, or even dislodge the
desirable plant when pulled. In that case a knife or other tool to carefully
cut the roots just below the soil line or below the crown of a grassy weed may
allow you to manually remove the weed while doing minimal damage to the desired
plant.
Further away from your garden plants you
can use a hoe to manually remove the weeds. I like to use a scuffle hoe
that cuts the weeds roots just below the soil line. The weed can then be
raked from the garden. A scuffle hoe disturbs the soil less than a
chopping action type hoe which disturbs the soil and brings new weed seeds to
the surface where they can sprout and perpetuate the weed problems.
Another way to minimize weed problems is
to use mulch to cover the soil and reduce weed growth. Some gardeners use
black plastic under their plants. The black plastic eliminates sunlight
needed for germination of weed seeds, but it can become hot enough in New
Mexico’s sunlight to burn the garden plants. A covering of organic mulch
may help avoid overheating. The organic mulch (straw, wood chips,
newspaper, or other biodegradable material) may be used without the plastic as
well. A thick layer will also exclude light and reduce weed seed
germination. Perennial weeds may still come through the mulch since they
do not need light to germinate, but the mulch will help maintain soil moisture
making the weeds easier to pull. Organic mulches also moderate soil
temperature changes and may protect plants from our intense summer heat.
The soil in direct sunlight can be 10 to 20, or more degrees, hotter than the
surrounding air.
Weeds you have pulled can be composted to
use as soil amendment in the garden next year if they are not diseased or have
not produced seeds. If your compost pile heats properly the weed and
disease concerns become lessened. Another way to be sure weed seeds do
not germinate next year is to put the weeds into a black plastic bag in a sunny
location for a few days before putting them into the compost. The weeds
should be freshly pulled so that they are still moist when you do this.
They heat of the sun will kill most of the weed seeds and potential plant
diseases in a few days in the solar heated plastic bag. There should then
be less concern about perpetuating the weeds with the compost next year.
If you eventually become so frustrated
with the weeds that you decide to use chemicals, be sure to choose a product
labeled for use around the desirable plants you are growing and then read,
understand, and follow the directions.
Send
your gardening questions to Yard and Garden, Attn: Dr. Curtis Smith, NMSU
Agricultural Science Center, 1036 Miller Rd. SW, Los Lunas, NM 87031. You may
also send to cwsmith@nmsu.edu or leave a message at https://www.facebook.com/NMSUExtExpStnPubs. Curtis W. Smith, Ph.D.,
is an Extension Horticulture Specialist, retired from New Mexico State
University’s Cooperative Extension Service. NMSU and the U.S. Department
of Agriculture cooperating.
