How to Kill Sedge Grass in a Vegetable Garden
There are more than 900 types of sedge -- a fast-growing, grasslike plant that loves moist, sunny locations -- found throughout North America, making it one of the most common weeds you'll encounter in your vegetable garden. Don't let sedge rob your vegetable plants of the soil space and nutrients they need. Using a combination of mechanical, chemical and cultural controls, you can kill sedge and create an environment that is unfriendly toward this vigorous weed.
Water your vegetable plants only when absolutely necessary and apply water directly at the base of each plant instead of using a sprinkler or indiscriminately spraying the entire garden. Sedge requires moist growing conditions, and its appearance generally means you're over-watering your vegetable patch. Letting the soil dry out will often quickly kill this weed.
Arrange your vegetable plants as closely as possible in tight rows to shade the soil, and consider intermingling thin, tall vegetable plants with large, leafy vegetables, such as lettuce or chard. This helps shade the vegetable garden and because most sedges cannot tolerate shade, it may weaken or kills existing sedge while reducing the growth of new sedge.
Pull the sedge out by hand by grasping the weed at its base and pulling upward. Hand weeding typically leaves behind the weed's roots and it will regrow, but constant removal forces the plant to use its energy to produce new shoots, and doing this once every two weeks will generally overstress the sedge and kill it.
Spray the sedge with herbicide if all other methods of control and eradication don't suffice. For the best results specifically against sedge weeds, the herbicide must contain one of the following chemicals: sulfentrazone, bentazon, imazaquin or halosulfuron. Apply the herbicide according to the manufacturer-specific guidelines as toxicity and potency varies widely by product, and avoid getting the herbicide on any of your vegetable plants.
- While landscape fabric and other mulches often keep weeds out of your vegetable garden, they don't generally work for sedges.
Joshua Duvauchelle is a certified personal trainer and health journalist, relationships expert and gardening specialist. His articles and advice have appeared in dozens of magazines, including exercise workouts in Shape, relationship guides for Alive and lifestyle tips for Lifehacker. In his spare time, he enjoys yoga and urban patio gardening.