Posted on

weed and feed new grass seed

Before you plant grass seed, you should always prepare the area by removing any weeds that may be growing in the location. Even with careful preparation of the planting site, weeds can still develop among the newly planted grass seed. Weed killers, however, can harm grass seeds and seedlings if applied too early or improperly.

A general rule of thumb is to wait at least until you have mowed the new grass four times before using any standard postemergent broadleaf herbicide. A standard pre-emergent herbicide should not be applied until at least three to four months after seeding the area.

Application Timing

Weed management should be completed before seeding the lawn with a non-selective herbicide seven to 14 days before you till the soil. A second application of the herbicide may be required to kill any weeds you missed during the first treatment. Wait another seven days until tilling the soil if a second application is used.

Some pre-emergent herbicides can safely be used during seeding and usually come mixed with a seed starter. These products have the active ingredient Siduron – also known as Tupersan – that works by suppressing weed seeds while improving root development of the new grass. The fertilizer and pre-emergent herbicide mix is applied with a drop or rotary spreader using a rate of 2 1/2 pounds per 1,000 square feet. The spreader setting and actual application depends on the brand of starter fertilizer plus weed control you use, and you should always follow the instructions found on the label.

Remember that all herbicides are different and the exact time you must wait to apply weed killers to newly planted grass will vary from one product to another. Also, some herbicides cannot be applied to certain species of turfgrass. For best results, always refer to the herbicide bottle’s label.

However, you can get rid of these weeds just as fast as they have appeared.
The important thing to remember when new weeds appear in your newly sown lawn is not to act hastily – do not apply a Feed, Weed and Moss Killer type product of any kind on a newly sown lawn.

Although this can be frustrating and we can appreciate that a quick solution will be desired, the good news about these types of weeds is that they are largely shallow rooting and should come out with the first mow at the 6-8 week mark after sowing. If they don’t, they should be easy to pull out of the turf.

In short, here’s what you should do if you encounter weeds in your newly seeded lawn:

If you find that the weeds are recurring past the 6-8-week mark, you may wish to consider using a selective herbicide to spot spray your weeds. Some weed killers such as glyphosate (Roundup) kill more than just weeds, so it is important to not apply these as if they are not done precisely, they can kill your grass. Shop bought selective weed killers will recommend when to apply their product and how often and you should read the instructions thoroughly and adhere to them.

If you find that when the lawn is at least six months old and has been taken over by weeds or moss, you can use a Feed, Weed and Moss Killer product.

With any new lawn area, avoid using crabgrass preventer fertilizers or weed & feed fertilizers within four weeks before planting time. After seeding, wait until your new grass gets established and you’ve mowed your lawn at least three times.

Between August and November, grass slows down and prepares for the winter months. At the same time, broadleaf weeds start active growth again. With Pennington UltraGreen Winterizer Plus Weed & Feed Fertilizer 22-0-14, you can feed your northern or southern lawn nutrients essential to its winter prep and spring green-up — and kill broadleaf weeds. As a general rule, allow six to eight weeks between fertilizing and your first expected frost.

When and How to Fertilize Established Lawns

On fertilizer products, phosphorus is the middle number in the N-P-K ratio — usually “0” in normal lawn fertilizers. But with Pennington UltraGreen Starter Fertilizer 22-23-4, you get an ideal ratio of nitrogen, phosphorus and potassium, plus other essential lawn nutrients, including iron for deep green color. This premium fertilizer blend starts feeding new grass immediately and keeps feeding it for up to three months.

In some ways, lawns are a lot like people. Operating at the peak of beauty and performance requires a good diet and proper care. Lush, thick, green lawns depend on properly timed, properly balanced nutrition to look and grow their best. Understanding when and how to fertilize your lawn can help you and your grass stand out from the rest.

To keep your existing lawn looking its best year-round, choose a fertilizer plan that meets its changing seasonal needs. At Pennington, we make it simple for northern and southern lawns. Just follow our four-part annual lawn fertilizer program: