Post emergent herbicides kill weeds after they appear. Some post-emergent, systemic herbicides that you can apply directly on lawns only kill weedy grasses, while others only kill weeds with broadleaf weeds. Contact herbicide such as those including the active ingredient glyphosate kills on contact. To use one of those on a lawn without killing the grass you have to daub it on individual weeds.
You can sow grass seeds now and kill weeds later with a post-emergent herbicide or kill weeds now with a pre-emergent herbicide and plant the seeds later. Weed-and-feed fertilizers are specially formulated combinations of turf fertilizer and herbicides that you apply either before you plant grass seeds or on established lawns.
You apply pre-emergent herbicides before weed seeds germinate, typically in the spring. Pre-emergent herbicides do not prevent weed seeds from germinating; they suppress the development of weed roots as they germinate. They’re usually effective for two weeks to three months, depending on the formulation, and you have to water the lawn after applying for the herbicide for it to be effective. There are pre-emergent herbicides to kill both broadleaf weeds and weedy grasses. You can apply them before you sow your grass seed. If you apply a pre-emergent herbicide that kills weedy grasses, you have to delay sowing your lawn seed.
Fertilizers containing pre-emergent herbicides selectively prevent certain kinds of weeds from finishing their germination cycle. There is no point applying this type of weed-and-feed mix after weeds are growing on your lawn. You have to apply it early in the growing season before weeds appear. Make sure the pre-emergent herbicide in the fertilizer kills the kind of weeds that have plagued your lawn in the past. You might apply a starter fertilizer containing a pre-emergent herbicide before you sow your lawn seeds.
Post-emergent weed-and-feed formulations kill selective weeds that are already growing in your lawn. Make sure that the herbicide in the formulation you buy kills the type of weeds that are growing in your lawn. Most weeds make their appearance in the spring, the best time to apply weed-and-feed fertilizer.
It can take up to four weeks for the herbicide effective to fade, so sowing grass soon after applying weed and feed is likely futile because new grass won’t be able to grow.
A plan weed and feed product to your lawn may seem like a perfect way to kill two birds with one stone. Not only are you can to get eliminate irritating weeds however the chemical contained within the product additionally can facilitate the grass to thrive. Weed and feed products aren’t ideal for all situations though and may cause some problems if you plan to receive the lawn soon after their application.
Weed and feed products work by preventing new growth, effectively stopping weed seeds from sprouting and newly sprouted wheat from flourishing. However, the herbicides used are insufficient to target weeds only; grass grains and any new grass growth are the same.
Hindering New Growth
Ideally, you should plant seeds well enough before frost in the autumn so that the new grass will grow for several weeks before sleep. You can also sow grass seed in the early spring, though if you do so you should hold off on applying weaving feet for at least four to eight weeks to ensure it doesn’t damage the young grass.
If you must sow grass seed after applying weed and feed, wait for at least four to six weeks before doing so to ensure the herbicide won’t prevent the seeds from sprouting. Prepare seedbeds with the help of a rake which is one of the important garden tools that every gardener should have. It helps the seeds to have proper contact with the ground and prevents any bare patches.
What Is Weed And Feed
In order to activate, most weed and feed products are granular and should be applied to moist grass. Mow 2 – 4 days in advance and use the weed and feed products for best results, without additional rain for at least 48 hours. After application, do not mow the treated grass for at least 7 days to allow the herbicide time to work.
Weed and feed products, as the name implies, contain both a fertilizer and a herbicide to control weeds while feeding the surrounding grass. If the lawn has grass that is already established, this works well. The product should ideally be applied just a couple of weeks after the final frost when grass and weeds grow visibly because it is not effective for sleeping weeds. Apply it periodically throughout the rest of the year as well to keep weeds under control.
Answer: If you have more than 75% grass, you may be surprised how your good grass will fill in with four feedings a year at 6 to 8 week intervals. With this option you skip spring seeding (you can always seed in fall if your lawn still needs it). Here is a schedule for the year: Feed your lawn now with Scotts Turf Builder with Halts Crabgrass Preventer. In 6 to 8 weeks after your first feeding, feed again with Scotts Turf Builder Weed and Feed if you have lots of weeds or if you only have a few weeds, your second feeding can be Turf Builder Lawn Food and spot treat your weeds with Ortho Weed B Gon MAX plus Crabgrass Killer OR Roundup For Lawns. Put down Scotts GrubEx sometime in May or June. In 6 to 8 weeks after your second feeding, feed again with Scotts Turf Builder with SummerGuard to control insects. In 6 to 8 weeks after your third feeding, in late summer/early fall, feed with Turf Builder Lawn Food.
Answer: If lots of larger spots, then seed this spring. Be sure to use a special Starter Lawn Food plus Weed Preventer that is compatible with grass seed (the regular crabgrass preventers will keep grass seed from growing). If you do not prevent weeds when you seed, you are likely to be very disappointed as crabgrass and other weeds will germinate and choke out your good grass before it has a chance to take hold. A machine called a slit-seeder will help make sure the grass seed comes in contact with the soil. You just select the Turf Builder Grass Seed blend that is right for your conditions, such as sun, shade, heat-tolerant, etc. If you only have a few bare spots to take care of, consider Scotts EZ Seed. I think this is the best bare spot repair product we have ever sold! Spread the Starter Lawn Food plus Weed Preventer after you put down the seed. Feed your lawn again in one month after seeding with Turf Builder Lawn Food. Once your new grass has been mowed 4 times, you can kill weeds with Ortho Weed B Gon MAX plus Crabgrass Killer OR Roundup For Lawns.
Do you have less than 75% good grass with bare spots larger than a few inches in diameter?
Weed, Feed or Seed?
This is a big question in early spring: “My lawn needs everything what should I do first, put down seed or kill my weeds? The reason why this question is tricky is because many of the weed controls will harm new grass seedlings.
Here are your best two options:
Do you have more than 75% good grass however your lawn is thin and weedy without widespread bare spots?
If you have questions during the year, the Scotts Help Center folks will be happy to help you.