In the quest for a lawn that is free of crabgrass and other weeds, the application of a pre-emergent herbicide that kills seedlings before they become an unsightly nuisance is a powerful weapon. Preventing crabgrass with pre-emergent herbicide is actually the most effective way to rid your lawn of this common grassy weed.
What is Pre-Emergent Herbicide?
Pre-emergent herbicides are weed-killing chemicals that are applied to your lawn or garden before weeds appear. The chemicals form a protective barrier in the soil, killing crabgrass and most types of summer annual weed seedlings as they emerge, preventing them from taking root. To be effective, pre-emergent herbicides must be applied before seeds germinate. If applied after germination, they will not kill weeds. Preventing weeds like crabgrass before they appear is much preferred to treating them after they are already established. In fact, once crabgrass has had the opportunity to emerge, it is very tricky to get rid off. Pulling it can actually lead to spread because as the grass stolen (root system) is removed from the ground, hundreds of tiny seeds have the opportunity to scatter. That’s why your best chance to beat crabgrass is with pre-emergent weed applications.
What Time of Year Is Pre-Emergent Herbicide Applied?
Generally, pre-emergent weed killer is applied in early spring. The exact month of application will depend on where you live: February or March in a warm southern climate, and April in a cooler northern climate. Remember, this must be done before the weeds germinate. If weeds are already visible in the lawn, then a post-emergent weed control product will be needed.
How Is Pre-Emergent Herbicide Applied?
Pre-emergent herbicides are sprayed on the lawn in a liquid form or spread in a granular form. Your lawn care specialist will decide which formula is appropriate for your application area. Pre-emergent weed killers are lawn-safe and will not harm your existing lawn when applied correctly and in the right amount. For proper application, it is best to consult an experienced professional. After application, the weed killer should be watered in if rain is not expected.
Will Pre-Emergent Herbicide Last All Season?
In order to get long-lasting results from a pre-emergent herbicide, it should be applied in two split applications, about a month to six weeks apart. This ensures that the product will handle the early germinating seeds in spring and continue to kill emerging weeds into the late summer months. The split applications will make the herbicide’s effectiveness less likely to be diminished by excessive heat or rain.
If you have any questions about controlling weeds like crabgrass with pre-emergent herbicides, or if you are interested in starting a turf management program, our lawn care professionals will be happy to help.