AMES, Iowa -- Controlling weeds in home gardens and lawns can be a busy job, and Iowa State University horticulture specialists Ajay Nair, Adam Thoms and Gail Nonnecke tackle frequently asked questions.
How do I control weeds in my asparagus planting?
Weeds compete with asparagus for light, water, and nutrients and will reduce asparagus yield and quality if not controlled. Cultivation and hand pulling are the best ways to control weeds in an asparagus planting. Hoe or till the planting periodically in spring and early summer. Cultivate lightly to avoid damage to emerging spears. Under severe infestation or to manage larger areas, Gramoxone or Roundup can be used for weed burn-down before spears emerge. After the final harvest, Roundup could be applied directly to the weeds, strictly limiting any herbicide exposure to cut asparagus stalks.
How do I control dandelions and other broadleaf weeds in my lawn?
In small areas, some weeds can be controlled by pulling and digging. This method is best accomplished after a soaking rain or deep watering. Unfortunately, pulling and digging is often ineffective on deep-rooted weeds.
In many situations, herbicides are the only practical method of weed control. Effective broadleaf herbicides include 2,4-D, MCPP, MCPA, dicamba, triclopyr and others. The most effective broadleaf herbicide products contain a mixture of two or three herbicides as no single compound will control all broadleaf weeds. Fall (mid-September to early November) is the best time to apply broadleaf herbicides in Iowa. Broadleaf herbicides can be applied as liquids or granules and often in combination with fertilizer. Note that a preemergence herbicide for crabgrass will not control broadleaf weeds.
How do I control weeds in my strawberry patch?
Weed control is essential to ensure optimal plant growth and fruit production. Weeds compete with the strawberry plants for water, nutrients and sunlight. Weeds also reduce air circulation, which results in fruit and foliage staying wet for longer periods. Disease problems are more serious when plant tissue remains wet for long periods of time.
Cultivation, hand pulling and mulching are the most practical weed control measures for home gardeners. Cultivate often, but shallow, to control weeds. Destroy the weeds before they have a chance to flower and produce seeds. Clean, weed-free straw and other organic materials can be applied as a mulch between plant rows in a new or established planting. Herbicides are not a viable option as few, if any, herbicides can be used on home strawberry plantings. If an older strawberry planting becomes too overgrown with perennial weeds, and cultivation or hand pulling does not provide sufficient control, a new weed-free location should be selected for establishing a new planting. Replanting of strawberries is common every five to seven years in home gardens.
During and after renovation of a Junebearing strawberry planting is an excellent time to control weeds by cultivating or mulching between the rows and cultivating within the rows until daughter plants begin to form roots. As daughter plants establish, hand-pulling is best so that the new plants are not disturbed as they grow and fill the row area. In day-neutral strawberry plantings, using straw or a colored (not clear) polyethylene mulch within the row helps control weeds. Hand pulling of any weeds may be necessary near the original strawberry plant that is maintained without daughter plants. Weed control in between rows of day-neutral strawberries is achieved by cultivating or applying an organic mulch, such as weed-free straw.
How do I control weeds in my garden?
Cultivation, hand pulling, and mulches are the primary means to control weeds in the home garden.
Cultivation and hand pulling effectively control most annual weeds. Perennial weeds are often more difficult to control. Repeated cultivation or the use of herbicides may be necessary to destroy some perennial weeds. When cultivating the garden, avoid deep tillage. The roots of many vegetables, fruits and flowers grow near the soil surface. Deep cultivation will cut off some of these roots. Also, deep cultivation will bring deeply buried weed seeds to the soil surface where they can germinate. Hoe or till around plants or between rows and pull weeds close to plants. To effectively control weeds, cultivation and hand pulling must be done periodically through the growing season. Small weeds are much easier to control than large weeds. It’s also important to destroy the weeds before they have a chance to go to seed.
Mulches control weeds by preventing the germination of weed seeds. Established weeds should be destroyed prior to the application of the mulch. In addition to weed control, mulches help conserve soil moisture, reduce soil erosion, prevent crusting of the soil surface, keep fruits and vegetables clean, and may reduce disease problems.
Grass clippings (do not use grass clippings from the first three mowings after a herbicide application), shredded leaves, and weed-free straw are excellent mulches for vegetable gardens and annual flower beds. Apply several inches of these materials in early June after the soil has warmed sufficiently. Plant growth may be slowed if these materials are applied when soil temperatures are still cool in early spring. Grass clippings, shredded leaves, and similar materials break down relatively quickly and can be tilled into the soil in the fall.
Wood chips and shredded bark are excellent mulches for perennial beds and areas around trees and shrubs. Apply two to four inches of material around landscape plantings. These materials decay slowly and should last several years. However, it will be necessary to apply additional material periodically to retain the desired depth.
Herbicides can be used to supplement cultivation, hand pulling and mulches.
Can I place weeds and diseased plant debris from the vegetable garden in the compost pile?
It would be best to place weeds that are producing seeds and diseased plant debris in biodegradable bags and have the material picked up and composted by a municipal or commercial composting facility. The temperatures in home compost piles seldom get high enough to kill weed seeds and disease pathogens. However, the weed seeds and disease pathogens will be destroyed by the higher temperatures at municipal and commercial composting facilities. The compost produced at composting facilities can often be purchased by home gardeners and commercial landscape companies.