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Are the Weeds Winning?

Published: Fri Aug 4th 2017

This has been a good growing season. Regular rains and not too many super-hot days means plants are thriving. Especially the weeds.

The best weed-pulling weather is a day or two after a rain when the soil is still moist and loosened, but not soppy wet. Last Saturday my kids and I made quick work of cleaning up a portion of the flower beds that was driving me crazy. Goldenrod, red-root pigweed, and oxalis just popped right out of the ground.

There are a few ways to get rid of weeds. The most straightforward is pulling, but that is not always practical.

String trimming taller weeds especially along bed edges and road hillsides where pulling is not easy is the best solution here. Weed-eating before they go to seed and propagate themselves further is the goal. At the farm we start at one end and work our way around the greenhouses. Then begin again.

Smothering weeds with cardboard or plastic is effective in the vegetable garden or where you want to plant new beds. Plastic weighted down with rocks between the rows helps to heat the soil in the spring for new transplants, yet prevents weeds from germinating underneath. It also stops evaporation from the soil, helping to retain moisture. If you leave plastic in place over the winter, you are a step ahead in controlling the weeds the next season.

Herbicides are another choice. Pre-emergent herbicides are applied before the weed seeds germinate. This is best used twice a year in the late winter/early spring and again in late summer before annual weeds like groundsorrel, pigweed and spurge appear. Often this is used in a mixture in “Weed n Feed” lawn supplies. Do not use this type in the vegetable garden or your peas, beans, corn seeds etc won’t come up.

Post-emergent herbicides are either “burn down” meaning they kill the top growth mostly, or systemic meaning they are also transported to the roots. Systemic herbicides are best applied in the fall when perennial weeds are storing reserved sugars in their roots for the following year. The chemical is taken down to the roots and kills the weeds.

There are also herbicides that select for broadleaf weeds, and do not affect grasses. Many of these herbicides like 2-4,d are highly volatile when the temperatures are above 80. When using this type of herbicide in the summer, you have to be really careful what you are near. Dicamba was in the news earlier this summer as drift from farm fields was damaging neighboring crops and trees.

Concentrated acetic acid, corn gluten meal and propane weed flaming are used in organic farms to control weeds with varying degrees of success. Corn gluten meal works as a pre-emergent when applied heavily for several years. Acetic acid (vinegar) works best on small young weeds as a “burn down” and will kill within a few days any plant tissues it touches. However, as it doesn’t reach the roots and perennial weeds can resprout. Flaming appeals to the pyromaniac in me, but works like vinegar only killing top growth. This also is dangerous as dry grass can easily spread a fire, and you must also be mindful of wooden structures and other flammable items nearby.

The truth is, if you are going to garden, you are going to get weeds. Hand pulling is the safest, most selective method. Mulching well with wood or plastic sheeting works well to prevent weeds. Selectively spot treating with herbicides and/or organic alternatives will help hold weeds at bay.

I always thought pulling weeds was good therapy. Better go see my therapist.