By Bob Dailey
While winter-dormant St. Augustine lawns have yellowed, something is going on under the soil.
Winter weeds are beginning to germinate. And a lot of weeds do well here. Plantain weed, nutsedge, henbit, spurge, purslane, chickweed, and thistle are a few of the unwanted guests that plague our lawns in late winter and early spring.
Don’t despair. St. Augustine is the best weed-suppressing grass there is, followed only by Zoysia. Both are aggressive plants and, if properly maintained, will keep the weeds to a minimum, if not entirely eliminate them.
Weeds do like compacted, poorly-drained soil, bereft of available minerals, nutrients and organisms.
Residents who apply organic matter to lawns in mid-fall and mid-spring have already established a strong defense against weeds. And although these are ideal times to spread organic matter, anytime is okay. Aerating the lawn before adding organic matter is another step in the weed war. The organic matter helps soil to drain, and simultaneously holds enough water to establish a strong root system, and is the first and most important step in having a beautiful lawn.
Winter weeds start poking their heads up when the first string of warm days come in January or February. The best method to get rid of them is to simply pull them up and dispose of them in your green waste. Mowing them down before they seed also gets rid of them, but a grass catcher is necessary to keep the weeds from falling back onto the ground.
But weeds are ornery and persistent. Even in the most well-cared-for lawn, it’s probable that a few plantains and thistles are going to pop up. While “manufactured” herbicides may not be the best choice, there are a few products available to the environmentally conscious homeowner.
Agricultural vinegar is available at many garden stores. It is tried and tested and will destroy even the most persistent weeds. It even works on that super weed – nutsedge. Just be careful. Agricultural vinegar is much stronger than the normal white vinegar that most people keep in their kitchens. Wear gloves (preferably rubber gloves) when applying.
One application of agricultural vinegar eliminated a sizeable stand of nutsedge growing in the Alden Bridge Community Garden recently. Ammoniated soap of fatty acid or potassium soap of fatty acid are also effective herbicidal treatments for weeds, though more effective on plantain, wood sorrel, and spurge.
Whether using vinegar or soap of fatty acid, it’s not necessary to spray a whole area. Simply spot spray each weed. A spray bottle works well.
While corn gluten has been touted as a great pre-emergent herbicide, but there seems to be some disagreement as to its ability to suppress weeds. It’s also extremely expensive.
Whatever method residents use, creating a healthy lawn is an ongoing process, not an isolated event.