Hello Deb,

Thank you for contacting the UNH Extension Infoline regarding your inquiry about Rye Grass in Vegetable Garden.

Following up on your email from 5/7/2026, I’ve attached some general information to help get you started.

We are committed to finding the right solution for your lawn and garden and are happy to provide further guidance as needed.

Please feel free to reach out with any further questions.

Best regards

Haim
Master Gardener Volunteer
UNH Extension Infoline Team

General information

To clear your vegetable garden in New Hampshire and get those seeds in the ground, you need to "terminate" the rye grass immediately before it goes to seed. Rye is a hardy cover crop that often survives the winter and returns aggressively in the spring.

1. Terminate the Rye Grass

Since you need to plant seeds soon, you have three main options to manage the grass:

Mowing and Tilling (Quickest): Mow the grass as short as possible. Use a tiller to turn the grass and its roots into the soil. This speeds up decomposition, but be aware that if the rye was already forming seeds, tilling might just spread them.

Tarping (Organic/No-Till): If you have a few weeks, cover the grass with a heavy black plastic tarp or silage tarp. This starves the grass of light and creates heat that kills both the plants and many surface weed seeds.

"Chop and Drop" (Manual): For smaller beds, use a weed whacker or scythe to cut the rye at the soil level. Leave the clippings as mulch and use a broadfork or shovel to loosen the soil where you plan to plant your seeds.

2. Manage the "Nitrogen Tie-Up"

A common trap with rye grass is that as it decomposes, soil microbes "rob" nitrogen from the soil to break down the tough grass fibers. This can leave your new vegetable seedlings stunted.

Wait: Ideally, wait 2–3 weeks after tilling or chopping before planting to let the initial decomposition finish.

https://colsa.unh.edu/resource/perennial-ryegrass-forage-species-new-hampshire

https://www.pennington.com/all-products/grass-seed/resources/all-you-need-to-know-about-perennial-ryegrass