Weed Control Without Chemicals
There currently is a growing movement with gardeners and farmers alike to reduce or eliminate the use of chemicals for controlling weeds. One of the main reasons people are avoiding weed killers is that more and more there is increasing evidence of the damage herbicides can do to the soil. Another issue people are taking with these chemicals is the potentially nasty side effects. This graphic we’ve created below goes over some of the negative effects of herbicides and how to control weeds without chemicals. Enjoy!
Controlling Weeds Without Chemicals
Nothing can crush a gardener’s spirit like weeds. It’s not uncommon for a promising season with
tidy, weed-free rows to turn into an entangled nightmare as the weeds rapidly outgrow the plants
you’re planning on to provide food for your family.
Weeds have a bad rap because they tend to outcompete the desirable plants we’ve either spent
months nurturing before planting outside, or spent hard-earned money at the local nursery, for
nutrients and moisture. On their own, many have excellent qualities, and some might even be
considered superfoods, but when they aren’t where you want them, weeds need to go.
How to handle the onslaught of vigorous growth is the problem. There is growing evidence
indicating that the use of popular herbicides doesn’t break down shortly after application, as
often touted, and could be causing longterm issues in the soil. Because of this, while it’s easy to
grab a bottle to spritz away the problem, more and more gardeners want to steer clear of toxic
chemicals. Fortunately, there are plenty of ways to keep the situation under control for the
immediate season and beyond. First off you need to know what you’re dealing with.
Correctly Identify the Weeds in Order to Know How to Control Them
To effectively combat the weeds in your garden, you must understand the specific varieties in
your area and how to best handle them. This doesn’t mean that the botanical lingo of everything
green in your garden needs to roll off of your lips, but at least you should have an idea the proper
name and the life-cycles of various plants. Many times different plants have the same common
name leading to confusion not only as to the type of plant, but how to deal with it.
One of the best places to go for weed identification and information is your local Extension
office which coordinates with state universities to provide sound scientific advice for gardeners
and farmers. Many counties have a Master Gardener program where volunteers are available in
the Extension office specifically to answer such questions, and if they don’t have the answer,
they can typically find someone who does. Bring in the weed itself, or at least a photo, and
explain the growing conditions in order to receive advice on how best to deal with it. In worst
case situations, sometimes the Master Gardeners will actually come out to your place to assess
the situation and offer advice.
If you can’t tap into Extension resources, look to fellow local gardeners. Veteran growers are an
invaluable source of information on the typical weeds in your region. Truthfully, there are times
when these long time gardeners know more than the ones who have learned what they know
from books. And, even if you’re a new gardener, you’ll discover that plant people love to talk
about their chosen vocation offering tips you might never have considered.
One of the biggest reasons to know your plant is to decide how best to kill it. For example,
annual weeds, such as pigweed and lamb’s quarters, are the fast growing ones that reseed by the
middle of the summer. These are the ones that often give you fits early in the year, as they
seemingly grow as fast as you can pull them, so the key to suppressing them is tenacity and
consistency. If you can gain a handle on them early in the year, you are avoiding all the seeds
they would have produced during the season.
Biennial Weed Control
Biennials, such as great mullein and wild carrots, complete their life cycle in two seasons. The
first year, there is moderate growth, and they form seeds the second season. They are more
vulnerable during this first year of growth, making it the opportune time to take them out before
they have the chance to produce seeds to continue the cycle.
Perennial Weed Control
For many gardeners, perennials are the most challenging of the bunch since they are built for
long-term survival. Some, such as the dreaded field bindweed, have roots reaching over 20 feet
deep and rhizomes stretching horizontally just as far. Bindweed is so bad, it has driven a number
of organic farmers out of certified organic production in order for them to utilize chemical means
to gain control over it. If its impact is this significant for farmers, you know home gardeners will
have just as difficult of a time keeping it in check. And bindweed is just one of many perennial
varieties that don’t easily give up.
Occasionally, you can pluck a long tap-rooted weed, such as spotted knapweed or dandelion, out
of soft soil. Consider that a victory. Other times, pulling and breaking them off only creates more
issues, and heaven help you if you run a rototiller through a perennial weed batch. More often
than not, you’re aiding the plant’s ultimate goal of reproduction by chopping up the root and
regenerating plants all over the place.
This isn’t to say that manual removal of perennial weeds isn’t beneficial. Sometimes that’s all
you can do. Take bindweed again. While there’s no way to affect the root system without using a
systemic herbicide, chopping at the plant continually to weaken it and it may succumb to the
constant stress. I’ve actually heard of some farmers utilizing pigs to stress the plant. Chickens or
goats very well could have the same affect.
You can use other means to weaken the plant. Some people rely on the burner to weaken the
perennial weeds, as well. It won’t kill them as it does the annual weeds, but continual use will
stress even the perennial plants.
Other home gardeners turn to vinegar as a homemade weed killer, but this isn’t the same type
that you put on your salad. While there are plenty of claims that apple cider vinegar will kill
weeds, and it might in some instances, for more consistent weed elimination, use the
horticultural vinegar that has a 20% acidity level versus the 5 % in home canning or cooking use.
You can usually find it in garden centers or via online sources. Because it is so much higher, and
keep in mind that this is an acid, wear gloves, eye protection, and preferably long sleeves and
pants when you’re working with it.
The vinegar mixture is also best used on areas where you don’t have desirable varieties nearby,
as the vinegar and salt combination can affect the growth of surrounding plants. It’s great in
driveways or in the cracks of sidewalks, but don’t spritz the weeds around your tomatoes.
To fill a gallon sprayer, mix 1/2 gallon of the horticultural vinegar with 1/2 gallon of hot water.
Add 1/4 cup salt and roughly a half-teaspoon of dishwashing liquid. Pick a hot, dry, sunny day
to spray away. You should see wilting within 6 hours.
Annual Weed Control
When you’re dealing with annual weeds, consistency is the key. The trick to controlling them is
not to allow them to live long enough to reseed. By doing so, you’re saving a lot of headache in
the future. If a gardener can be on top of weeds with a hand tool or stirrup hoe from the moment
they show their little green leaves, they not only eliminate current plant competition, they reduce
the pressure in the subsequent year. But when the weeds are growing like gangbusters during the
spring, which is also one of the busiest seasons for gardeners or homesteaders, it’s not always
feasible to spend the required time in the garden.
Utilizing a pre-emergent, such as corn gluten, where the dipeptides in the processed corn meal
suppress seed germination by inhibiting root formation, is one tool (and possibly an organic one
with some brands) to use in around established plants such as vegetable or flower transplants,
trees, or shrubs.
Keep in mind, if you sprinkle corn gluten over a newly planted seedbed, you won’t have weeds,
but you won’t have any vegetables, either. After you plant transplants sprinkle it around the area
to minimize the number of weeds you’ll have to deal with the rest of the summer. It won’t take
care of every one of them, but you’ll notice a difference. The downside of corn gluten is that it
can be pricey to cover a large garden, but for smaller areas it’s an excellent tool to gain a handle
on the annual weeds. You can also apply it at the end of the season to help reduce the number
germinating in the fall.
The Best Tools for Killing Weeds
Taking care of weeds when they’re still tiny is the best way to keep annual or biennial weeds
from completing their lifecycle. This means grabbing your hoe or favorite garden tool to scratch
the surface and eliminate the weeds before they have time to grow much at all.
Choosing the right tool is completely dependent on what you prefer. The fanciest, ergonomically
perfect weeder isn’t going to make a difference if it’s not comfortable for you. For those who
prefer to hunker down close to the soil and tackle the weeds head-on there are plenty of hand
tools, such as the Cobrahead® with its gnarly looking blade, or any number of tools that help
you scratch, slice or dig. Even the single bladed digger can be practically all you need. Try a
number of them to see what works for you the best.
If you’re a gardener who might manage to get down on your hands and knees to garden just fine,
but can’t seem to get back up, you’ll want a longer handled tool to attack the weeds. Many
gardeners love the ease of the stirrup hoe. You simply run it over the top of the soil to slice out
tiny weed seedlings. A collinear hoe also cuts the tender weeds off at soil level, but turn to a
common hoe if you need to chop off tougher weeds. The wheel hoe is another favorite of many
gardeners because, once mastered, it is easy to use and efficiently eliminates most small weeds.
Whatever tool you use, it’s important to water the area several hours prior to weeding to allow it
to soak in around the weeds’ roots. Nothing is more frustrating than hacking away at weeds that
hold to the soil as if they’re set in concrete. On the flip side, you don’t want to water
immediately before weeding, or you’ll slog in the mud more than accomplishing much of
While there is a certain Zen-like quality to hand weeding the garden, using fire is a bit of a thrill
and offers a lot of satisfaction. Flame weeding has been around for decades, and with various
propane fueled burners, it’s easy for the home gardener to put a dent in the annual weed
population. Of course, when using fire, please make sure there is no breeze and no risk of having
the weeds burn out of control. Always keep a hose and shovel handy to extinguish any flames in
case the fire jumps beyond your intended target. And wear heavy shoes or boots, long pants,
gloves and eye protection to keep from being burned yourself. While flame burning is probably
the most enjoyable way to weed, it is also potentially the most hazardous.
Flaming is best done when the weeds are small, although you can still knock back the ones that
got away from you, if you weren’t able to keep up. Fire up your propane burner every couple of
weeks to singe newly emerging weed seedlings with an added bonus of killing seeds that are
right below the surface of the soil.
Even though annual weeds are extraordinarily vigorous early in the season, if you stay after
them, you can make headway. This isn’t as readily said about their perennial cousins.
Solarizing Your Garden to Kill Weeds
If you’re putting in a new garden, or have an overgrown area of your garden that defies all
efforts, look to the sun to do the hard work when it comes to weeds. Solarizing the area, which is
simply heating it up under plastic, does a banner job of cooking out many perennial plants.
Clear plastic heats up more, but in areas where the air temperature is cooler, black works better
because it also blocks out the light, in addition to heating the soil. You simply have to keep the
black plastic on for a longer period of time to do the job. You can buy a heavy 6mm type of
plastic (often used in greenhouses) if you’re going to leave it on for many months, or want to do
multiple areas over a number of seasons, but it’s typically not necessary if your goal is to
eliminate weeds in a particular area. Purchase a less expensive option that may not last for half a
year without forming holes, but will still do the job in a shorter amount of time.
To solarize your garden space, spread down the plastic, and pin it down as tightly as possible to
minimize any air circulation. Then let it heat up for at least 6 weeks. Keep in mind that tough
weeds, such as quack grass, may need an entire season.
Use Mulch to Prevent Weeds
Once you have a handle on the weeds, mulching is a big help in keeping it clean. You don’t have
to buy anything fancy. Use a thick layer of straw, chopped up leaves or shredded bark. The
important part is to be generous with them.
For the pathway spread cardboard or 6 to 8 layers of newspaper (they use soy ink anymore so
there are no issues of odd chemicals leaching into the soil) as a barrier, and simply dump the 6 to
8 inches (because it will compress) of mulch on top of it. If any weeds happen to poke through,
they’re incredibly easy to pull since it’s difficult for their roots to take hold. The cardboard and
the mulch will eventually break down, and turns into a gorgeous compost rich with earthworms.
To keep up the positive cycle, add more mulch as necessary, especially since walking on them
will pack down the materials.
You can spread 3 to 4 inches of mulch around your plants, without directly touching the stems, as
long as you don’t have significant problems with slugs or other pests that use the mulch for a
perfect path that leads directly to your vegetables. The mulch not only helps suppress the weeds,
it aids in retaining moisture.
The Chop and Drop Method
There is a growing movement of implementing permaculture techniques into home gardens
where the problem becomes the solution. In respect to weeds, a way permaculturalists utilize
them is by allowing them to benefit the soil, either by adding green matter when the weeds are
small, or creating a mulch with larger plants.
If you want to make positive use of the weeds, such as keeping them as a covering for the soil
without having them grow out of control, one option is to chop them down before they have the
opportunity to go to seed. Depending on how wide your paths are between your rows, you can
run a lawn mower between them to cut the weeds to a manageable height. This allows the main
crops to thrive without competition, while taking advantage of the benefit of deep roots or the
biomass left on top of the soil after cutting. If you can’t use a mower, trimming the weeds by
hand or a weed whacker is perfectly acceptable. The weed parts left on top will serve double
duty as a mulch.
And while it might seem counterintuitive to many gardeners, there are times when leaving weeds
in place can be a boon to the garden, particularly when they provide a nectar source for
beneficial insects. or a trap crop to the undesirables. Queen Anne’s lace and dandelions are both
attractants for beneficial insects such as the lacewings, and if you have issues with either cabbage
webworms or mustard aphids, leave some of the mustard growing around your cabbage plants to
attract the pests.
Weeds are undoubtedly one of the greatest factors that discourage gardeners since they quickly
can overtake an area, potentially decreasing production. But by staying proactive, it is possible to
get the best of them and enjoy a productive garden.
Common Weeds and Solutions
CANADA THISTLE (Cirsium arvense) – Repeated applications of vinegar is sometimes
effective. So is solarization and dedicated hand weeding.
BERMUDAGRASS (Cynodon dactylon) Control with constant hand weeding, solarization and
FIELD BINDWEED (Convolvulus arvensis) – Relentless hand weeding, flame weeding,
vinegar applications, and long-term solarization work, but it’s a long process any way you
CREEPING CHARLIE (GROUND IVY) (Glechoma hederacea) – Continual hand weeding
can control it, but it’s not easy. Vinegar might weaken it, as well.
QUACK GRASS (Elymus repens) – Cook them out under plastic, then mulch heavily. Or a
couple applications of the vinegar mixture will often kill it, particularly in driveway situations.
LAMBSQUARTERS (Chenopodium album) -Weed them out when they’re small. You can also
burn them. Or you can simply eat them since they are considered highly nutritious and rather
WILD MUSTARD (Sinapis arvensis) – Till or hoe them out when they are less than a half-inch
high. Using corn gluten early in the season can also make a difference.
JOHNSON GRASS (Sorghum halepense) – Like quack grass, you can solarize it under plastic
and mulch heavily, or dose it with the vinegar mixture.
CRABGRASS (Digitaria sp.) Use a pre-emergent or weed it out early, and then mulch to
prevent its return.
CHICKWEED (Stellaria media) – Seeds stay viable for decades so use a pre-emergent and
weed any that do sprout early in the season. The vinegar solution also works, and in terrible
cases solarization will do the trick. Chickweed is also considered highly nutritious so if you can
beat ‘em, eat ‘em.