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 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.
Pre-Emergent Weed-and-Feed Fertilizer
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.
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.
For a simple, all-in-one approach to a thicker lawn, you can put your lawn on the fast track with Pennington Lawn Booster. This easy-to-use product simplifies overseeding to give your lawn the boost it needs. In just one application, your lawn will grow quicker, thicker and greener than ordinary grass—guaranteed.
The basics of overseeding are the same everywhere, but goals and timing vary based on geography and the type of grass grown. For success with overseeding your lawn, follow this basic guide:
The premium fertilizer in Lawn Booster stabilizes nitrogen in the soil, to reduce leaching and other nitrogen loss to the environment. Your seed gets nitrogen for immediate feeding and for extended feeding for up to eight weeks, without extra fertilizer inputs on your part. Moreover, the soil-enhancing gypsum in Lawn Booster corrects soil conditions to allow for better root growth, so your newly boosted lawn can flourish and be the talk of the neighborhood.
Spread Your Seed
For troubles beyond normal thinning, test your soil and make corrections before overseeding. Follow test recommendations for using soil amendments and repairing bare lawn spots. If needed, take time to dethatch and core aerate compacted lawns so air, moisture and seed can get to the soil. Pennington One Step Complete products combine premium seed with a stabilized-release fertilizer and wood mulch to simplify lawn repairs.
Keep your newly revived lawn looking its best with a regular, comprehensive maintenance plan that includes diligent watering, best mowing practices and proactive overseeding. A simple weekday lawn maintenance schedule can keep your lawn lush and your weekends free.
Pennington, One Step Complete, Smart Seed, and Ultragreen are trademarks of Pennington Seed, Inc.
Avoid weed & feed products; the pre-emergent herbicides inhibit seed germination. Starter fertilizer, such as Pennington Ultragreen Starter Fertilizer 12-22-8, delivers essential nutrients for new grass. Phosphorus supports vigorous root growth, while nitrogen fuels top growth and greening. Some states and counties restrict phosphorus lawn fertilizers due to environmental concerns regarding runoff, but exceptions may be made for new seedings. Check with your local county extension agent about nutrient application restrictions.