Weed Control Without Chemicals

Organic Landscaping in Lawns, Garden Areas

Dandelions gone to seed among dandelions still in bloom.
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"Weed control without chemicals" may conjure up unpleasant thoughts of getting down on your hands and knees in the yard on a hot day and pulling out stubborn weeds by hand. But suppressing weed growth without compromising your organic principles need not be so primitive. Learn about a variety of measures to use to keep plant pests from taking over your vegetable gardens, flower borders, planting beds, and lawn areas.

Use these measures in conjunction with each other for best results. Weed removal without resorting to potentially dangerous chemical herbicides can be tough work. Learn how to work smarter, not harder.

Laying the Foundation

The first smart idea in a project of weed control without chemicals in gardens is to prepare the plot of ground in question. Just as in a construction project, laying a good foundation is of the utmost importance. In this context, "foundation" means the state of the ground where your plants will be growing (beyond its fertility, which is a separate issue). Put these ideas in place before you plant, so that you will get off to a smooth start on your project:

  1. Kill weeds through soil solarization: Soil solarization is a preventive, organic method of killing weeds before they even sprout. This method is meant for homeowners wishing to start out with a clean slate, re-landscaping a weed-filled patch of land in such a way as to reduce to a minimum the hassle of weed control in the future.
  2. Lay landscape fabrics: For those in need of soil solarization, installing landscape fabrics can be considered step #2 in the project of weed control without chemicals. For those with less weedy properties, it is step #1. Weed control without chemicals should not mean going back to the Stone Age, and landscape fabrics are a case in point. These barriers are a hi-tech ally in the battle against weeds. They are not always a good choice, though. Not every gardener loves using them. But if you are a beginner who adores gardening but hates weeding, you owe it to yourself to learn more about them. Experiment with landscape fabrics to see where they work best (and where they present too many drawbacks). They are most effective in shrub beds.
  1. Use garden mulch: As the final element in a good foundation for your bed of annuals, perennials, or shrubs, apply garden mulch on top of the landscape fabric. Mulch comes in extremely handy not only when fighting the plants most commonly thought of as "weeds," but also unwanted grass. In fact, there are several different ways to use mulch to get rid of weedy grass.

Many people skip right to mulching in their attempts to control weeds organically, but applying landscape fabric first will lengthen the life of your garden mulch, since it will not break down as quickly if it is not allowed to come into direct contact with the soil.

Pre-Emergent and Post-Emergent Organic Herbicides

"Pre-emergent herbicides" is a fancy way of referring to herbicides that attack annual weedy plants at the source: their seeds. They act to inhibit seed germination in the soil before the plants in question even have a chance to sprout. Corn gluten is an example of a pre-emergent herbicide used for weed control without chemicals; it is especially helpful in fighting crabgrass (Digitaria). Remember, corn gluten will inhibit the seeds of "good" plants from germinating, too, so do not use it in garden spaces or lawns where you are sowing seed.

By contrast, you apply post-emergent herbicides only after the weeds have appeared. For weed control without chemicals, try vinegar as a post-emergent weed killer. Even plain old household vinegar is effective if you have only young weeds to deal with in your planting bed (killing older ones requires a special, stronger vinegar). As with corn gluten, you have to be careful using vinegar as an herbicide, because it is an equal-opportunity killer: Being a non-selective herbicide, it not only kills weeds but also harms landscape plants that are accidentally exposed to it. Likewise, you can pour boiling water on weeds to kill them, but be careful not to get it on your good plants.

Crowding Out Weeds

Another way to stop weeds naturally is based on the premise that a good offense is the best defense. This is particularly true of lawn areas. Grass that is well cared for will grow in so thickly that it will largely crowd out weeds. Think of your lawn grass as being in competition with weeds for the building blocks of growth: nutrients, water, sunlight, and growing space. There is only so much of these to go around, and your job is to give your lawn grass an unfair advantage in the competition. If you do so, then you may only rarely ever see a weed in your lawn, especially if you put down corn gluten in the spring to suppress crabgrass.

You can try taking a similar approach to perennial beds. If you are not a big fan of mulch, simply pack your perennial flowers close together, thereby depriving weeds of the bare patches that they so love to exploit. You can also plant compatible ground covers between your flowers. But you must be vigilant. Weeds and weedy plants can be very sneaky. Years after seemingly getting rid of an invasive plant such as sweet autumn clematis vine (Clematis terniflora), seeds that it had deposited into the soil will sprout. Lurking among your perennials, it is easy for it to go undetected and re-establish itself unless you pay careful attention. So, while it is theoretically possible to use the crowding-out strategy in perennial beds, it is not as easy to do so as it is in lawn areas, where weed seedlings are more readily spotted.

In Case You Still End Up Pulling Weeds by Hand

With landscape fabric and mulch in place, the bad news is that, even then, you may still get weeds. But the good news is that those weeds will be very easy to pull out. Pulling weeds embedded in garden mulch is not nearly as difficult as pulling weeds embedded in soil. With that good "foundation" in place, you may not even feel the need to bother with corn gluten and vinegar: Five minutes of easy pulling here and there should get the job done.

One exception to this may arise: If the integrity of the landscape fabric has been compromised, weeds may strike down roots in the soil beneath, making them difficult to pull out. In this case, water the area in question beforehand. In fact, a general rule of thumb for weeding is that it is easier to yank out weeds from moist soil than from dry soil.​

There are even some weeds that you can eat after you pull them. Examples include: