Since I base a lot of my topics on emails I receive, one topic that has been very active is crabgrass. Crabgrass is a very common problem in many of our lawns. Crabgrass is actually a summer annual that germinates each year, mainly in the summer although in our area of Florida, crabgrass can be a nuisance almost all season. Since crabgrass tends to grow in large bunches, it can rapidly take over a lawn especially if it is not in the best of health. A single crabgrass plant can produce as many as 150,000 seeds! That is why the problem may seem to multiply season after season. Crabgrass is not only a problem in Florida but is a problem throughout the U.S.
Crabgrass is not only a nuisance, but it can be often difficult to control. Many of the herbicides that you can get over the counter are only effective if you have a lawn other than St. Augustine. Most crabgrass killers are actually herbicides for killing broadleaf weeds and this type of herbicide can cause browning of your lawn if it is St. Augustine or Floratam.
Fortunately, most crabgrass infestations are in other types of lawns such as Bahia and Bermuda grasses. If you have these lawn types you can use a crabgrass killer with good results
Your best defense is to use a pre-emergent weed killer that states it will prevent crabgrass on the label. This type of herbicide does not actually kill the existing grass, but kills the crabgrass seedlings as they germinate.
I emphasize that this type of treatment will only prevent the crabgrass that has not yet germinated. You can find these products at many local garden and hardware stores. Although you should follow label directions carefully, there are some general guidelines you should consider. Always apply the herbicide uniformly across your lawn as if you miss any areas, the seedlings will have an opportunity to germinate and do their thing. In addition, do not de-thatch your lawn immediately after applying the herbicide as the chemical barrier will be broken. Do not use a pre-emergent herbicide if you already have an infestation. In this case you should use a post-emergent herbicide to kill the existing crabgrass. If over the counter measures do not do the trick, then the use of a professional lawn service would be advisable.
I want to again stress that you read the directions carefully and follow them precisely to avoid damaging your lawn or the environment.
If you have the St. Augustine variety, you should only use Atrazine for your weed control needs. Although it will not be as effective as the other herbicides, it will provide a safe treatment that will not brown out your Floratam lawn. Atrazine is the active ingredient in such products as Scott's Bonus-S along with other brands of Floratam weed control products.
Please use any garden chemicals responsibly and use them only when it is absolutely necessary. Since chemicals can seep into the ground water, only use them when other methods have failed.
Before using any insecticide or herbicide, follow safe practices and use rubber gloves, safety glasses and a chemical respirator (if you are going to be spraying the product). Always use the appropriate amounts as excess chemical can make its way to the groundwater and contaminate your well. If you get the chemical on your skin, flush immediately with fresh water. Remember that many chemicals are absorbed directly into your bloodstream and can cause long-term problems if enough is allowed to enter your body. If you ever have any unusual symptoms after using a chemical lawn product, contact your doctor and take the bottle of the suspected poison with you.
Joe Zelenak has more than 30 years experience in gardening and landscape. Send e-mails to email@example.com or visit his website www.hometowngarden.com.