Overseeding Your Lawn: The Right Fertilizer

By: Ken Wilson

A lush, beautiful lawn not only makes your home look more attractive but increases its value by 10 – 15%. A healthy turf also comes with benefits like producing oxygen and trapping dust. However, having a lush lawn requires regular maintenance and care, and one of the best ways to do this is by overseeding it and applying the correct fertilizer.

A slow-release fertilizer like starter fertilizer is the best to use when overseeding. This is a nitrogen-based feed and releases nutrients into the soil gradually feeding the seeds. Organic compost can also be used to feed your lawn after overseeding.

As lawns age, they become thinner, lose some of their color, and don’t look as vibrant and healthy. Overseeding is an easy solution for homeowners who aren’t happy with their turf and are looking for an inexpensive way to get their grass healthy again. Reseeding repels insects, prevents weeds, and increases root growth, but you need a good fertilizer to get the most out of seeding your lawn.

What Fertilizer To Use After Overseeding?

A starter feed or organic compost is the best to use after seeding your turf. Starter fertilizers typically contain nitrogen, phosphorus, and potassium. This formulation usually has more phosphorus as it encourages root growth and helps the seeds root and grow faster.

Compost is another feed you can use when seeding. However, if using compost, you should be aware that the nitrogen in this organic matter contains uric acid. When uric acid is exposed to sunlight, it absorbs quickly. If you spread a thin layer, you must fertilize again to ensure your seedlings get sufficient nutrients to germinate.

If you prefer using compost instead of a starter feed, you can aerate your yard to get the most out of the compost. Aerating the yard before spreading compost allows it to sink into the soil to feed the seeds and helps keep them moist.

What Fertilizers Should You Avoid After Overseeding?

There are a few products that should be avoided when throwing seeds on your lawn. This includes feed for an established turfs or for mature grass and a weed and feed fertilizer. The established products contain little to no phosphorus, which isn’t sufficient for seeds. If you use this type of feed, the roots of the seedlings will struggle to root and grow, and they may even die.

Another product that should be avoided is weed and feed. This type contains a mix of herbicides and fertilizers and is strictly for an already established lawn. The herbicide in this feed will kill the seeds.

It’s also important to note that the herbicide remains in the soil for up to three months. So, if you’ve already applied weed and feed to your turf, it’s advisable to wait 12 weeks before you overseed.

When Should You Apply Fertilizer After You Overseed?

You can apply fertilizers to your lawn directly after spreading the seed on your grass. Some people prefer waiting a day or two, but you should fertilize within the first three days after seeding.

Avoid over-fertilizing your seeds. This can damage them, especially if it’s a newly seeded turf. Once fertilized, wait between six and eight weeks before applying it again. The best time to feed your lawn is late in the afternoon. You don’t want to burn your grass with it, so double-check that your products don’t need watering afterward.

How Do You Fertilize Your Lawn When Overseeding?

You can fertilize and spread the new grass seeds once you’ve prepared your lawn. Ideally, you’ll want to test the pH of your soil and find a suitable fertilizer that works with your soil’s pH level. It’s also important to consider the type of grass you have as well as your climate so you can determine the right time to overseed. If your yard has cool-season grass, you can reseed it between the end of summer and the beginning of fall.

Warm-season grasses do well when reseeded between the end of spring and the beginning of summer. Once you’ve found the best feed for your turf and spread the seeds, spread a thin layer on the turf.

Some homeowners prefer to fertilize before seeding, others do it simultaneously, and some fertilize after reseeding. This decision is mainly based on preference and the type of products you use. Some fertilizers do well when applied a couple of days after sowing seeds, while others work well no matter when they are spread.

Tips on Fertilizing and Overseeding

Besides choosing the right feed after seeding your yard, you’ll want to take good care of it so the seeds root and germinate, leaving you with a beautiful lawn. Here are a few tips to help you when feeding and reseeding your turf:

  • Use a spreader to help you overseed. This can be a drop, handheld, or broadcast spreader.
  • After fertilizing, water lightly, and for seven weeks, continue to water your yard three times a day.
  • Avoid mowing your lawn until the seeds have germinated.
  • Once the seeds have germinated, don’t mow the grass too short.
  • After the first feed, fertilize the grass again in six weeks. Repeat in another six weeks.
  • Avoid using weed killers until the new seeds have germinated and have had time to grow.
  • When mowing, mow high. Taller grass looks greener and helps your turf get thicker.
  • The new seedlings are more vulnerable to pests, disease, and weeds, so keep a close eye on it after sowing the grass.
  • Aerate your yard before spreading the seed. This helps the new seedlings root and allows the feed to sink into the soil.
  • Try to avoid any foot traffic on the turf after seeding. You want to give your new lawn a chance to root.

Final Thoughts

When choosing a feed for your turf after overseeding, make sure it’s a starter fertilizer or organic compost. This is the best food for your seeds and will not only help the health of your lawn but also help you achieve the lawn of your dreams.

About the author 

Ken Wilson

Long time career in the home services industry from remodeling to patio construction. Currently residing to in SWFL and active contributor to multiple home & garden publications.