The Q&A Archives: Too Many Weeds in St. Augustine Grass

Question: Hello,

I am a new homeowner and gardner and was told that my lawn was damaged by chinch bugs during the month of September and October. My grass is currently dormant due to the winter months, but I also have a lot of weeds. How do I get rid of the weeds and get the grass to grow back?

Answer: I don't think there is an easy solution. Start by hand digging the largest weeds or patches of weeds to remove them from your lawn. Then help your lawn become thick and healthy by following a regular maintenance schedule. Good lawn care can be summarized in three cultural practices: mowing, watering and fertilizing. If you will do these three properly, your lawn will be the best on the block! Frequent mowing is better than infrequent mowing. Mow on a 5-7 day schedule, removing no more than 1/3 of the leaf blade with each mowing. For example, a St. Augustine turf should be mowed to 2 1/2" when it reaches 3", while a semi-dwarf bermuda or zoysia would be mowed to 1 1/2 or 2" when it reached 2 or 2 1/2". While many homeowners like to water 15 minutes a day, your turf will benefit from a good soaking applied less often. Apply 1/2 to 1 inch of water once or twice a week. A coffee can makes a good rain gauge to test out how long it will need to be run to apply an inch. Frequent wetting promotes disease problems and a shallow rooted turf. Let the soil dry out a bit between waterings and the grass will develop a deep root system and do much better. Fertilize with no more than 1/2 to 1 pound of nitrogen in spring after you have mowed the grass twice, and again in fall (around late October). Apply a product with a 3-1-2 ratio of nutrients as this is roughly the ratio of nutrients grass takes in. So, for example, if you purchased a 15-5-10 fertilizer (15% nitrogen), you would apply about 7 pounds per 1000 square feet (1 pound / .15 = about 7). If you purchased a 21-7-14 fertilizer (21 % nitrogen), you would apply about 5 pounds per 1000 square feet (1 pound / .21 = about 5). Healthy turf will choke out most of its weed problems. When the turf is thin and soil is exposed to the sunlight, weeds will sprout and you have a battle on your hands. So first concentrate on the above 3 cultural practices and you will be amazed at the results. Thanks for the question. Best wishes for a wonderful gardening season. Please stop in again soon!

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