If I don’t point out that I projected the most common lawn questions that would be coming up just a few weeks ago here, one of you probably will. Or my editor won’t let it slip by. But a lot changed with that cold blast that blew through last week. It messed with our schedules because it messed with our springtime. And it certainly brought out the questions in people.
When should I apply my pre-emergent weedkiller since it was so cold so recently?
Because it was so cold, and because the cold fell when it did, the application timing for applying pre-emergent herbicides was moved later by 7 days. For the DFW area you need to finish your application by March 20-22. (Repeat the application 90 days later.) Products to use include Dimension, Halts or Balan.
I applied my pre-emergent granules a week before the cold weather. Do I need to apply them again?
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Not at all. The herbicide was in place and nothing about the cold caused it to deteriorate. You’re ready to go with your first application. Sit tight.
Why isn’t my pre-emergent weedkiller working on the big thistles and clover? The lawn is a mess.
By their very name, “pre-emergent” weedkillers must be applied prior to the germination of weed seedlings. The coarse, broadleafed weeds that you’re seeing currently all got their starts back in early fall. The preventive control is Gallery granules applied the last week of August or the first week of September. Any later than that and you’ll likely miss them. You can always address them later (as in “now”), however, with a broadleafed weedkiller spray with 2,4-D as an ingredient. Read and follow label directions implicitly.
What can I use to kill the crabgrass that is already growing in my lawn?
That is not crabgrass. Odds are quite good that you have rescuegrass. Its seedheads look like flattened hands folded in prayer. It’s a cool-season weed that soon will die in the hot weather. Pre-emergent granules applied in late August or the first week of September will stop its germination before it ever starts growing.
Now that my St. Augustine and bermuda are starting to green up, I’m seeing patches that are obviously dead. I’m going to have to plant new grass. When should I do that, and can I apply pre-emergent granules to those areas to prevent weeds?
The best time to plant new warm-season grass sod is April and May, but new bermuda sod can be planted almost immediately if necessary. Soils can still be pretty cold for St. Augustine to establish good roots. It would be better to wait 2-4 weeks for it if you can. As for seeding bermuda, that needs to wait until May. By then the soils will have warmed considerably. Do not apply pre-emergent products to new grass until it has been through its first winter, and don’t apply them where you intend to be planting new grass this year, either.
We’ve had a good bit of rain lately. Does the grass have to be dry when I apply pre-emergents? Do I need to apply water afterwards, or is the soil’s moisture enough?
Read and follow label directions. Most products recommend application to dry grass when the soil is somewhat moist. Most recommend that you water the area lightly immediately after the application to carry the pre-emergent into the surface of the soil. You do not need to soak the ground deeply.
I use a lawn care service, and the dates they come to treat my lawn never seem to coincide with the ones you recommend. Why is that, and whose dates should I follow?
Great question. If you’re been happy with the work they have performed for you, follow theirs. They obviously know what they’re doing. They have access to a different set of materials with different pre- and post-emergent properties, so the timings may vary. Plus, in all fairness, they can’t be on all of their customers’ lawns on the same day just because some guy determines that it’s a great day to apply pre-emergents and writes that in his newspaper column. You’re hiring them to have a great lawn, and if that’s what you’re getting, stick with them.