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.
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.
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.
Pre-Emergent Weed-and-Feed Fertilizer
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.
Always follow guidelines for the best time to plant grass seed for your region and grass type, then fertilize accordingly. For seed or plugs, apply fertilizer with a regular lawn spreader before you plant. If you’re starting a lawn with sod, fertilize after your sod is in place.
When and How to Fertilize Established Lawns
Weed & feed fertilizers kill tough weeds and feed your lawn.
Part 1 – Early Spring
By following these lawn fertilizer tips, you can keep your grass at the peak of performance, beauty and health. At Pennington, we take pride in providing you with the best in lawn fertilizers and expert advice to help you have a lawn you’re proud to own. Stay connected with our email newsletter for accurate, timely tips and offers to help you make the most of your lawn and home.
The professionals don’t use combined ‘weed and feed’ fertiliser products containing pesticides or weed killers.
They use a quality grass fertiliser and a separate weed killer or pesticide. At Lawnsmith we feel the same way so all Lawnsmith® Fertiliser is free of harmful pesticides and unless you are using our WINTER GREEN High Iron Lawn Feed you’ll get no staining of hard surfaces as is the case with most feed and weed. Liquid weed killers can then be used which are much more effective and safe once dry: