Can I Overseed the Lawn after Applying Crabgrass Pre-emergent?

Do not overseed areas where PREVENT, crabgrass preventer has been applied. PREVENT is a combination of spring fertilizer plus a powerful crabgrass pre-emergent and will prevent grass seed and grassy weed seeds from establishing. However, if you have a few barespots in the lawn, you can repair those spots using Uncle’s Seed Sandwich recipe. The goal of the Seed Sandwich is to get the grass seed above the vapor barrier that’s been created by the PREVENT.

Recipe for Uncle’s Seed Sandwich

Uncle’s seed sandwich is a simple process, just follow the easy steps below!

1. Apply Prevent

Apply PREVENT over the entire lawn using a rotary spreader and water it in with ½ inch of water within 48 hours of application. The watering activates the pre-emergent in the PREVENT and is a necessary step before continuing with the Seed Sandwich.

2. First Layer of Field Conditioner

Cover each barespot in the yard with a generous layer of weed free PrimeraFC. This first layer will protect the new seed by suspending it above the herbicide vapor barrier.

3. Apply Grass Seed

Apply your Grass Pad grass seed on top of this protective layer of PrimeraFC. Don’t skimp on the grass seed – more is better than less.

4. Add Second Layer of Field Conditioner

Cover grass seed with an additional layer of PrimeraFC, completely covering the seed. DO NOT USE BAGGED TOPSOILS OR COMPOSTED PEATS. Topsoil and composted peats are contaminated with weed seeds from the field it was taken. 

5. Water Area

Keep consistently moist with frequent light waterings.

6. Mow the Area

Mow the entire lawn as needed using a sharp blade on a day when the grass is not wet. 

 

Why Does the Seed Sandwich Work?

Turf grass seeds and weed grass seeds that are in or under the herbicidal vapor barrier of PREVENT are killed as the top shoot of the grass plant emerges from its seed coat at early germination.  A layer of PrimeraFC lifts and holds the seed above the vapor barrier. This insulating layer allows the top shoot to grow up and the roots to grow down through the vapor barrier and into the soil and get established.

Can I Overseed in the Spring if I Haven’t Applied Prevent?

Yes! Check out more information about How to Overseed your Lawn in the Spring Using Seed Safe.

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