The practice of organic weed control for your crops and gardens is not only good for the environment, but good for the health of you and your family as well. The potential harmful side effects of chemical herbicide use are many and the number of studies to support such claims is too numerous to list. Thousands of reports and government publications underscore this knowledge.
As one example, the number one ingredient in many commercial weed killers, glyphosate, is known to persist in the environment much longer than it is claimed to made by manufacturers. Heritable mutations have been observed in numerous amphibious species generations after receiving exposure levels many times less than the proscribed “safe” amount.
The producers of chemical weed killers have spent millions of dollars leading the average homeowner and gardener to believe that weeds are the bane of their existence and by using their point-and-shoot concoctions, herbal enemies are quickly dispatched to the outer rings of the nether regions.
Dealing with weeds organically does not have to be a lengthy ordeal and it does not have to be expensive, either. Below are several organic methods of weed control and their respective benefits.
Thermal Weed Controls
This sounds cool, but it is not high tech at all. The principle is simply to burn your weeds with a flame or by using the sun.
Soil solarization is a process of weed killing that uses clear plastic in the spring or summer to kill weeds. Generally, after an area is tilled but before desirable crops are sown, the existing seedbed will spring forth with any thousands of tiny broadleaf or grass-like weeds that are just waiting to suck up all the nutrients and water that you would prefer are steered to your plants.
By placing clear plastic over the tilled area, you are creating a greenhouse effect. Light energy from the sun will come through the plastic and shine onto the weeds. Not all of that light energy bounces back as light though; some builds up as heat. Since the cover is right on top of the ground, that heat is at the level of the weeds.
On a sunny day, it is conceivable the temperature on the soil surface under that plastic is as high as 130°F (55°C). This is high enough to kill young plants quickly and also to sterilize weed seeds that may still be at the surface.
This practice prevents those weeds from maturing to the point where they are a threat to your crops, and further prevents them from developing seeds to be a nemesis in the future. This method is only used before you have seeded or transplanted your crops, or occasionally after you have harvested and are done for the season.
Flame weeding is another method of thermal weed control. This is done with, as the name implies, a flame weeder. This is a propane-fueled torch that you use by scorching the foliage of any undesired weeds. This method can be done anytime weeds are present as long asit is contained to the intended weeds and not your plants.
Mechanical Weed Controls
Mechanical weed controls have been a mainstay of organic food production since the dawn of agriculture. Before mankind had chemical and hydraulic tools at his disposal, weed control was done by hand, simple tools or by careful cultivation.
The stale seedbed approach to organic weed control is very effective for controlling early weeds. After the soil is prepared in early to mid spring, it is left alone, much like as in the soil solarization method. Instead of covering the weeds, however, the soil is again tilled once the seedbed has germinated. A sowing of your desired crops occurs immediately after giving them a jumpstart on the weed seeds that have yet to emerge.
Hoes, roto-tillers, broad forks, rakes, and numerous other garden implements can be used effectively for organic weed control (and offer great exercise as well). Many gardeners get frustrated with this method if they wait too long to perform this task. Regular turning of the top inch or so of soil, especially in between the crop rows, is a good way to ensure that weeds do not get established and take over the garden area.
The term mulch generally conjures up images of shredded hardwood spread around one’s foundation plantings or trees, but it actually refers to any ground covering, living or otherwise, and is a great organic weed control.
Living mulches are those that are intentionally planted to cover the ground and out-compete weeds. In a conventional landscape, these are things like ivy, ajuga, or vinca vines. In a garden of edible plants that are usually replanted annually, it could mean other vining plants such as squashes or peas. Care must be taken so they don’t do too well and out-compete the other desirable crops.
Other living mulches are cover crops. These are intentionally planted green manures such as oats, vetch, or clover, with a purpose to hold the soil in place, add nutrients to it, and not allow weeds to proliferate. These are often planted during the off season but can be planted in rows between garden crops as a weed control option.
A less popular but effective method of using living mulch for weed control is to selectively allow some weeds to grow as a cover crop. When this is done, usually weeds that serve an additional purpose are chosen. Examples of this are letting edible weeds such as purslane or dandelions grow. The other main benefit to this approach is weeds provide an environment conducive to attracting and harboring beneficial insects in your garden.
Non-living mulches include materials that were previously living such as bark, straw, and grass clippings, as well as items such as newspaper and black plastic. These materials are compatible with organic gardening as they are natural materials and decompose. Even some modern plastics are bio-based out of corn or other degradable materials.
If a non-degradable plastic is selected, it will need to be removed at the end of the season. Plastic left in place can become a haven for unwanted animals and rodents such as voles and other field mice. As materials decompose (except for the non-degradable plastic),they can add additional nutrients to the soil. I am careful to say ‘can’ add, as some materials such as fresh wood chips or unaged hardwood mulch can actually pull nutrients out of the ground as they begin their decomposition process. It is best to use aged materials for this purpose.
A word of caution about using straw: if you are uncertain of the difference between hay and straw, it’s best to find out. Hay contains the seed heads of various grains and grasses that will get into your soil and germinate. You will be repopulating your seedbed with many thousands of undesirable seeds (unless you intend to grow hay).
Straw is only the stems of those same grains or grasses and should not contain any seeds. A tried and true recipe for organic weed control is to alternate layers of newspaper and straw. When done properly, it stays in place and provides season-long weed control.
There are numerous manufactured concoctions, many certified organic that can be sprayed on weeds to control them. They are all non-selective controls. The same precautions of preventing overspray and drift with chemical herbicides need to be observed when using organic ones.
Organic weed killers that inhibit seed germination (pre-emergence) are made from corn gluten. This method becomes more reliable with successive years of use, and should not be relied on as the sole method of organic weed control. It does, however, work to reduce the instances of seed germination by coating the seed, effectively blocking out the sun.
Organic herbicides that control weeds and grasses after they have germinated (post-emergence) are generally some combination of horticultural grade vinegar, acetic acid or citric acid, and other plant oils such as clove, garlic, or mint. Their effectiveness varies and none should be considered to be as effective as their chemical counterparts. They will kill or damage desirable plants just as much as weeds. Always defer to the manufacturers precautions on the bottle.
The Old-Fashioned Method
Although probably not what you want to hear, hand pulling of weeds is still probably the most beneficial method of organic weed control for both the garden and the gardener. It involves no chemicals, implements, or mulches. It not only gets you outside for extended periods of time, which has numerous psychological benefits, but you will gain the best understanding of what your plants need by spending time in the garden.
At ground level, you can assess their moisture level, inspect for insect pests, and note when the appearance of the first bud or fruit has occurred. There is no better way to understand your plants’ needs than to get down on their level and pull some weeds.
Find more methods for organic weed control here.