The most organic methods of weed
control would not include some of the ones that follow. However they can be used in to
spot treat areas or as you see fit. One method that can help when using a spray is to wrap
plastic around the plant foliage, spray, then close the bag, let 'em cook. This way you
keep the spray off the soil and only on your target. Anything beats using synthetic
herbicides. We recommend never using them! That aside...read on, you may find something to
help your situation.
Digging: From April through June dig perennial
weeds like creeping charlie, dandelions, burdock, and thistles. This is
the most effective time of year to hand weed since root reserves are at
their lowest in spring.
Boiling
Water: Obviously you must be careful where and how you use boiling water i.e.:
it wouldn't be practical for weeds in the lawn area, but is ideal to use in concrete,
paved and rock areas. This is simple and couldn't be more organic as an application.
- Bring a pot of water to a rolling boil. Quickly
pour it on the undesired plant. You may have to repeat this to insure results. Best to do
in the heat of the day, however don't overheat yourself!
Corn Gluten: You may have heard
of the product
"Amaizing Lawns" or other corn gluten products which have a
pre-emergent herbicidal effect on lawn weeds in the
early spring when they are germinating. Don't apply a spring nitrogen
fertilizer if you used corn gluten meal on weeds because corn gluten also supplies a
source of slow release nitrogen. It
works on the more common turf weeds and crabgrass. Corn gluten, a protein found in poultry
feed, is a by-product of the corn milling process. You may be able to
find a cheap source of corn gluten (like at feed mill companies) and you can try it yourself.
Here's how:
- In April or early spring
just when the grass is turning green apply 12 pounds of the powdery gluten substance
per 1000 sq. feet of turf area, using a fertilizer spreader with the setting adjusted as
needed. When you are done water the gluten lightly into the surface, which will help it
latch onto the germinating seeds.
Flame Weeding: The idea behind flame weeding is to kill weeds with an intensive
wave of heat, without disturbing the soil or harming the crop root
system. Since all plants are composed of tiny cells filled largely
with water, a thin blast of heat directed at the stalk will boil the
water within the cell. The pressure generated by this expanding water
will then explode the cell itself, rupturing a cross section of the
stalk. When this happens plant food and water cannot move from roots
to leaves and the plant withers and dies.
When flame weeding, the most effective method is to catch weeds
early, from 1-4 inches. At this small stage, flaming is nearly 100%
effective, whereas weeds over 4 inches are more difficult to kill
without an extended dose of heat.
By destroying cell structure in the plant leaf, the weed will no
longer put energy toward growth, so even on big weeds, you will see a
stunting effect or even a kill, depending on how established the root
system is and how long the plant was exposed to heat.
This
method can be done with a small propane torch, however for larger areas one of the weed
flaming torches is an excellent tool. Weed flaming has long been a practice on organic
farms in Europe. The point of flaming is not to charbroil the weeds, but heat them just
enough so that they wilt. This will heat up the cell sap in turn causing them to expand and
rupture.
Flaming can be used as a spot treatment in lawns. The grass is going to get singed,
however it will bounce right back. You may need to flame tough perennial weeds a couple of
times to get rid of them. Do not use flame weeding on poisonous
plants like poison ivy.
You will have to practice to get the technique down. On smaller weeds
a slow walk is usually the best pace. Do keep some water handy
when you are flame weeding just incase.
Soil Solarization
Using plastic to solarize the soil is an issue debated by many.
Does it destroy the soil structure? Can it be beneficial? It can be very useful in
weed control and for clearing an area of vegetation without the use of herbicides. The
beneficial soil organisms can take more heat versus the harmful soil pathogens allowing
them to make a speedy return after solarizing an area. The way it works is the plastic
concentrates the sun's energy which into turn heats the soil to a very high degree,
sterilizing it. Thus killing off soil dwelling pests, disease and weed seeds.
Depending on your climate solarization has
been shown to control Fusarium and Verticillum wilts, crown gall diseases, possibly
nematodes, grassy weeds and weed seeds. As for the nematodes; they have the ability to
survive higher soil temperatures. The deeper the heat penetrates the soil the better the
results. With optimum conditions disease and weed control can last up to three years.
Soil Solarization
Technique:
Soil solarization is best done during the heat of the summer. To begin you want to
till the soil to a depth of at least 8 inches. Rake out all debris, smooth the area so it
is as level as you can get it. Proceed to soak the soil to a depth of 18 inches. Make a
slight depression at the boundary of the bed. Stretch some clear 4 mil plastic over the
bed as tightly as you can, adhering it to the soil. Then use rocks, more soil, landscape
pins, whatever you have to secure it snuggly in place.
Next step is easy; let the area cook for at least 4 weeks. In cooler zones allow a period
of 6 to 8 weeks for best results. Remove the plastic. Till the soil lightly, you are ready
to plant.
In more northern climates the addition of manures prior to putting down the plastic can
help to speed the process via increasing the soil temps as the manure decomposes. This
will increase the level of gaseous ammonia in the soil giving the solarizing process an
extra kick. Maybe enough to control nematodes!
Another trick is to use two layers of plastic to create more of an insulating effect. This
will trap more heat.
You can also incorporate shredded vegetables from the cruciferous family (broccoli stems,
cabbage trimmings etc.) These vegetables have a known effect in ridding the soil of
Verticillum and Fusarium blights. Let the trimmings dry out in the sun until brittle. Mix
them into the top 6 inches of soil, proceed with the process.
Vinegar-Salt Spray: This
combination is strong and the salt will sterilize the soil where you use it. Be careful. This is
not recommended for concrete areas as it will corrode the concrete. What we find useful to
give you control for spot application is to get a veterinarian type syringe and inject
solution into the center of the vegetation you want to get rid of. For larger areas use as a spray.
This is more potent when done during hot weather, avoid watering the area for 24 hours.
Flush out your sprayer several times with water immediately after
use.
Recipe:
1.Mix 1 pound of salt with one gallon of 5% acetic acid white vinegar.
2.Stir until the salt dissolves.
3.Mix in one teaspoon of liquid soap or two ounces of molasses to act as
a surfactant.
4.Spray the foliage thoroughly or inject into the crown. You may have to repeat in a few
days.
Using Vinegar on it's own: Vinegar is biodegradable. It can
burn or even kill some weeds. Store bought vinegar contains about 5%
acetic acid. It is produced from grapes, apples or grain via
fermentation in anaerobic conditions. 5% vinegar works on some young
weeds, but higher acetic acid concentrations produced by distillation
(15%) and freeze evaporation (30%), are needed for effective weed
control. Vinegars degrade after a few days and will cause a temporary
decrease in the soil pH. Best results are obtained when using heated
vinegar as a daily application for three days. If you use any vinegars
with 15% to 30% acetic acid you must use extreme caution. Do not get
breath the fumes, get it on your skin or your clothing and wear eye
protection. Flush out your sprayer several times with water immediately
after use.
Update:
04/17/08
