How do I remove weeds from my vegetable garden?
It is well known that weeds are unsightly and troublesome plants.
In lawns, they disrupt the lush, green carpet effect that we seek to achieve. Worse still, weeds invade vegetable gardens where they reduce yields and product quality.
Weeds compete for available moisture, nutrients, sunlight and growing space. They also serve as cover for insects, alternate hosts for disease, and hiding places for rodents and snakes.
Weed control is an essential step in maintaining a productive vegetable garden. There are several ways to control weeds.
Be careful with soil amendments. Although barnyard manure is a good source of fertilizer, it also contains weed seeds. Compost the manure before spreading it on your garden plot. Plant crops at the correct depth in soil that has been tested and received the appropriate amounts of lime. Vegetables that get off to a good start in good soil can often suppress weeds with rapid growth and dense vegetation that shades the ground. Vegetables good for weed control through shading include beans, squash, tomatoes, potatoes, pumpkins, sweet corn, and cucumbers.
Avoid watering the whole garden, which promotes excessive weed growth. Try using drip irrigation to place water directly on the plant. Hoeing and pulling weeds or cultivating with a rotary tiller is labor intensive but very effective in controlling weeds. Weeds should be removed when they are less than three inches tall and as often as every two weeks. Avoid deep cultivation once the garden is established, as this will bring new weed seeds to the surface and possibly damage the roots of the vegetables.
Mulches can prevent the germination of weeds. You can choose organic or inorganic mulches. Both are equally effective, but inorganic mulches will need to be removed from the garden each season, while organic mulches can be left or plowed into the ground. Commonly used organic mulches include bark chips, rotting sawdust, compost, newspapers (shredded or layered), and straw. They should be applied three to four inches deep around the base of vegetable plants.
Organic mulches should be applied in May or June after the ground has warmed up. Plastic is the most frequently used inorganic mulch. Black plastic can be laid in early spring to help increase soil temperature and therefore planting time. Fertilizer should be worked into the soil before laying the plastic.
After it has been in place for about a week, transplant the vegetables into holes cut in the plastic at the recommended spaces. Transparent plastic can be used in summer. Placed on the ground during hot weather, it will act as a greenhouse promoting the emergence of weed seeds. Weeds trapped under the plastic will die quickly from the heat. In some cases, temperatures can get high enough to kill many ungerminated weed seeds in the top two inches of soil.
A cloth mulch is very effective in preventing annual weeds and could be applied in the spring. It allows air and water to enter the soil, but prevents weed seedlings from becoming established. Cost is often prohibitive for fabric mulch in gardens.
Before planting crops a non-selective herbicide such as Round-up can be applied to kill existing weeds (autumn, late winter or early spring). Round-up should not be used where vegetables are present as injury may occur. Trifluralin (Treflan) can be used as a pre-emergent herbicide to control weed seedlings in gardens. This product is available in granular or liquid form but is not safe for all vegetables. Read the label before use.
Emergent grasses less than four inches tall can be controlled with a post-emergence herbicide containing sethoxydim (Poast). As with Treflan, this product is not safe for all vegetables and you should check the label.
The combination of cultivation techniques, mulches and herbicides will help vegetable crops perform better and increase yields, but perhaps the most important benefit is that it reduces the time you have to spend pulling weeds. herbs in your garden this year.
P. Andrew Rideout is the University of Kentucky Horticulture Extension Officer at the Henderson County Extension Office. You can reach him by email at [email protected]