Weed Control

Weeds make work! Nature is primed to cover the ground, and weed seeds multiply a plenty. The problem with weeds:

• Weeds rob moisture and minerals from your crops
• Weeds compete for row space and sunlight
• Some weeds exude root inhibitors stunting your crop roots

Weeds have to be controlled. Various methods have been used, and let's review them.

1. Hoeing is the most common method with the small market gardener. It was well utilized when I was growing up, and our two boys have gotten familiar with the idea as well.
2. Mulching is providing a thick blanket of organic material such as leaf mold or compost. The sunlight is blocked, and the weed seeds germination is inhibited.
3. Plastic ground cover is where the farmer covers the field in plastic, and transplants directly into the plastic. It is effective for weed control, but I am not convinced it is environmentally sound. The plastic is not reused.
4. Flame weeders are effective as heating the weeds just enough to burst their cells, and the weeds die shortly thereafter. You can plant your seeds, and just before the good seeds come up through the soil you can flame weed, and decimate all of the weeds that have already germinated. You don't have to burn the weeds to a crisp, just heat them enough to kill them.
5. Vinegar spray is used for weed control when the weeds are very small.
6. Chemical herbicides are not suggested due to their long half life in the soil, and dangerous components.
7. Flooding is used to benefit some crops like rice, where the crop can survive the flood, but the weeds die.
8. Tractor cultivation this is hoeing on a grand mechanical scale. Row spacing has to match the tractor wheel base to facilitate multiple passes as the growing season progresses.

While I have done all of these methods, we currently we use hoes and mulches. I have some vinegar to test how that works this spring. The goal with any weed control plan is to kill the weeds off when they are small. The larger the weed, the more effort needed to kill it. Grasses have underground rhizomes which make them especially hardy. If possible, dig up and remove the rhizome. The best time to kill weeds is just after they have germinated, but before they have true leaves. When you disturb the top inch of soil, you may see small white root threads. This is the easiest stage of all to kill the weeds. A simple disturbing of the soil will do the trick. It will dry out into a dry dust layer that does not promote weed seed germination.

Mulching will prevent working the weed seedlings, but itself provides a barrier for weed seeds through blocking light to the seeds, and by the thickness of the mulch, to kill the weeds that do germinate before the weed penetrates the mulch layer.

For flame weeders, it is suggested to prepare the seed bed, and then let the ground sit for a few weeks before planting your crop, and water it and stimulate the weeds to germinate. This is called a "stale bed". Then plant, and flame the bed just before your crop seedlings emerge. This will kill back all of the germinated weeds. If you do not stir up the soil bed later too much, you will not have as many new weeds germinating. Studies indicate flaming is effective with weeds 4" or less. Weeds allowed to grow 6" or more are not easily controlled with flaming. Beds of carrots and beets are especially suited for flame weeding.


Resources:

• FlameWeeders.com
• Mulch Gardening Video (video)