Q. What steps can I take now to avoid a weed problem in the spring? It seems that as soon as the weather warms up, the weeds go crazy and I can’t keep up!
Although weeds are mostly a warm-weather problem, there are some things you can do now that will make springtime gardening more pleasurable.
Fall is the ideal time to plant perennials – the weather is cooler, and rainy season is only a month or two away. Beds should be cleared of any unwanted plants, including weeds. When removing weeds, try to get as many roots as possible. Once the area is clear, water generously and wait a week or two. Any weed seeds still present will germinate, and these new weeds can be removed. Repeat this process until there are very few weeds emerging (you’ll never get all of them, since weed seeds are constantly blowing in).
If there are extremely persistent weeds present, such as Bermuda grass, nut grass, crab grass, bindweed, or oxalis, you may want to solarize the soil. First, clear the area of as many weeds as possible. Rake the soil smooth and water thoroughly. Cover the watered soil with heavy-weight, clear plastic sheeting. Try to maximize contact between the plastic and the soil by weighing it down with rocks or bricks. Leave the plastic in place for up to six weeks for best results. This process uses the sun’s energy to raise the soil temperature enough to kill weed seeds and many soil-dwelling pests.
When planting a new bed, try to plan for as much coverage as possible so the ground is shaded. Remember the saying “If you have weeds, you don’t have enough plants”. If the new plants are not frost-sensitive, encourage them to grow quickly so that they fill in completely. New growth on frost-sensitive plants will be subject to damage if we have an early cold snap, so avoid fertilizing these.
Drip irrigation can limit weed competition by delivering water only to desired plants. Drip lines can also be adjusted to accommodate plant growth. Applying a thick (3-4 inch) layer of organic mulch not only suppresses weeds, but also protects shallow roots from overheating in hot weather. We like to use fresh, untreated grass clippings for mulch around young vegetable plants since they form a cohesive mat that is very effective at excluding weeds.
When weeds do appear, remove them before they flower. Deep-rooted weeds can be pulled using a stick weeder or pointed, narrow trowel (take care to avoid cutting drip lines). Very young weeds can be scraped away with a hoe. If you are diligent about removing even just the top growth, the weeds will eventually exhaust themselves and die.
Los Angeles County
mglosangeleshelpline@ucdavis.edu; 626-586-1988; http://celosangeles.ucanr.edu/UC_Master_Gardener_Program/
Orange County
ucceocmghotline@ucanr.edu; http://mgorange.ucanr.edu/
Riverside County
anrmgriverside@ucanr.edu; 951-955-0170; https://ucanr.edu/sites/RiversideMG/
San Bernardino County
mgsanbern@ucanr.edu; 909-387-2182; http://mgsb.ucanr.edu