Weed control in vegetable gardens

Department of Horticultural Science Horticulture Information Leaflet 8101 Revised 4/93 - Author Reviewed 2/99 WEED CONTROL IN VEGETABLE GARDENS David W. Monks and Larry Bass Extension Horticultural Specialists ■ Weeds are unwanted plants in gardens that reduce available moisture, nutrients, sunlight and growing space needed by crop plants. Their presence can reduced crop growth, quality and yield. In addition, they can make harvest difficult. Weeds also provide cover for diseases, insects and animals (rodents, box turtles, snakes, etc.). Garden weeds are hard to control because they grow rapidly, produce vast numbers of seeds, and spread aggressively by vegetative structures and/or seeds. There are several methods that should be used in a combined, coordinated effort to control weeds. They include cultural, mechanical and chemical methods. Cultural Methods Fast growing vegetable crops can effectively suppress weeds by shading. Thus, one method of weed control is to select a crop that is capable of suppressing (shading) weeds. The following vegetable crops are listed according to their ability to suppress weeds. Suppression of weeds by crops works best when the crop germinates quickly an gets a head start on weeds. To achieve this, plant crops at the proper depth, with adequate moisture and fertility. Also, it is important to purchase high quality vegetable seeds or transplants that are free of weed seeds or seedlings. Garden soils should be tested and soil test recommendations followed to stimulate rapid crop growth capable of weed suppression. Fast growing ‘smother’ crops can be used to reduce weed germination in succeeding crops. For this purpose, smother crops are usually planted in the fall and killed by tillage or chemicals the following spring prior to planting vegetables. The straw residue from smother crops (i.e. rye, ryegrass, etc.) can inhibit early season germination of weeds such as common lambsquarters, common purslane and redroot pigweed by 75% or more. NOTE: Avoidplantingsmothercrops where small seeded crops such as lettuce will be seeded the following year or reduction in germination can occur. Smother crops are Distributed in furtherance of the Acts of Congress of May 8 and June 30, 1914. Employment and program opportunities are offered to all people regardless of race, color, national origin, sex, age, or disability. North Carolina State University, North Carolina A&T State University, U.S. Department of Agriculture, and local governments cooperating. Ability of Crops to Suppress Weeds Good Poor Squash Beans Pumpkins Peas, southern Cucumbers Com, sweet Melons Potatoes, Irish Sweetpotatoes Tomatoes Lettuce Carrot Pepper Greens Onions Peas, garden (English) Broccoli and Radishes Cabbage North Carolina Cooperative Extension Service NORTH CAROLINA STATE UNIVERSITY COLLEGE OF AGRICULTURE & LIFE SCIENCES