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 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.
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 years, professionals lived by a simple rule when establishing a new lawn or overseeding: never apply weed control as it will limit the ability to raise a healthy stand of turf. This meant that weeds had free reign to germinate and compete with the new turf for up to a full month. Then they would need to be controlled once the turf was established.
Now there’s a new product with pre-emergent weed control that you can apply when you seed –whether bare-ground seeding or overseeding.
This product is a game changer: Healthier new turf with fewer noxious weeds to eradicate later. Invest less effort and get instantly better results.
The 35% slow release nitrogen from methylene urea insures continuous feeding throughout the early stages of the plant’s life, while the Mesotrione controls weeds for up to 6 weeks. Weeds sprout white and then die quickly without harming the new grass.
Lebanon’s ProScape® Starter Fertilizer 21-22-4 with Mesotrione is ideal for use during turf establishment (bare ground seeding, sodding, sprigging or plugging), renovation or overseeding. The mesotrione ingredient is a game changer that offers pre-emergence control of 33 listed broadleaf and grassy weeds. It even controls crabgrass!
Excessive fertilizing can result in lawn burn, which is when the nitrogen and salt levels in the soil are too high and cause yellow to brown strips or patches of dead grass. A lawn, as with any type of plant, only needs fertilizing if the soil lacks the vital nutrients to help it grow. In situations like these, fertilizing your soil is essential.
Warm-season turfgrasses grow best with average soil temperatures between 80 and 95 degrees Fahrenheit. Warm-season grasses thrive in warmer climates found in the Southeastern and Southwestern United States and include Bahia grass, Bermuda grass, carpet grass, Saint Augustine grass, and zoysia grass (Japanese lawn grass).
Before You Buy
Weed-and-feed products come in two forms: liquid and granular. Although the liquid forms are easier to apply and provide faster results, it’s more economical to use the granular form. Spray or liquid weed and feed are designed for small yards.
Choose a weed-and-feed product based on the type of grass you have. Grass species have different nutrient requirements, so not all of them are safe for every species of grass. Using the wrong product can damage your grass.
In general, grass species are divided into two categories: warm season and cool season. The seasons do not refer to the time of year, but the climate and average soil temperature range.