How long until I can over-plant grass seed after spraying Weed b Gon I have 5 acres of backyard that used to be farmland. I planted grass, but I think I used the wrong kind, as it doesn’t seem to How Long After Using Weed B Gon Can You Plant Grass Seed?. Keeping your lawn weed-free is a constant battle that uses cultural practices, such as deep waterings, to encourage grass to choke out weeds, as well as chemical products, such as using Weed B Gon, to kill weeds before they start. These chemicals often kill … How Long After Using Weed Killer Can You Sow Seed?. Using a pre-emergent weed killer on your grass helps keep pesky weeds from marring the lush, even look of your lawn. Whether you use granule or spray types, don’t plant grass seed for several weeks after applying the herbicide. This holds true if you’re using …
How long until I can over-plant grass seed after spraying Weed b Gon
I have 5 acres of backyard that used to be farmland. I planted grass, but I think I used the wrong kind, as it doesn’t seem to be spreading. Now ~5 years later, the yard looks decent, but the grass is fairly thin and the weeds (dandelions mostly) are starting to get heavy. So I sprayed Weed B Gon on it, and now want to over-plant grass seed.
I’m not concerned about getting it perfect. If 10% of the seed I put down comes up and starts to spread over the years, I’d consider that a win. Every amount above that certainly welcome, but.
I just sprayed today, and it’s supposed to rain in 2 days (and a few days in a row). I was hoping I could toss down the grass seed tomorrow before rain, but I wasn’t sure if that’s too soon, or if it matters with this particular chemical.
Can I over-plant grass seed a day after spraying Ortho Weed B Gon? If not, how long do I need to wait (and why)?
How Long After Using Weed B Gon Can You Plant Grass Seed?
Keeping your lawn weed-free is a constant battle that uses cultural practices, such as deep waterings, to encourage grass to choke out weeds, as well as chemical products, such as using Weed B Gon, to kill weeds before they start. These chemicals often kill grass seed as well, keeping it from germinating along with the weed seeds, so wait before you sow your seed.
Without Crabgrass Preventer
How long you must wait to plant grass seed after treating your lawn with a Scotts Weed B Gon product depends on which product you use. When fighting broadleaf weeds such as dandelions with the basic Weed B Gon weed killer, wait at least three weeks to sow your grass seed. This product specifically targets the seeds of broadleaf weeds, but it can stop or slow down your grass seed’s germination as well.
With Crabgrass Preventer
When fighting grassy weeds, you must wait a little longer to plant your grass seed, whether you’re seeding your entire lawn, overseeding or treating bare patches. With the Weed B Gone Plus Crabgrass Control, wait at least four weeks to plant seed. Because this is specially formulated to stop grassy weed seeds from germinating, it also can stop your regular grass seed from growing.
Weed and Seed Together
Although you can’t spread grass seed at the same time you spray your lawn with Weed B Gon, other options exist to treat your lawn for weeds at the same time you plant seed. These typically come in the form of weed and feed products that offer fertilizer along with the herbicide. Look for products specifically designed to be spread with grass seed, often noted on the label as a starter fertilizer plus weed control.
After Planting Seed
When you’ve already planted your grass seed and want to apply a pre-emergent herbicide to keep weeds from competing with your new grass for water and nutrients, have a little patience. Applying a weed-control product such as Weed B Gon too soon can kill young grass. Instead, wait until you’ve mowed the new grass at least three times before using herbicides on your lawn.
How Long After Using Weed Killer Can You Sow Seed?
It makes sense to be cautious about sowing seed after using weed killer. Certain herbicides can harm sprouting seeds and young plants. However, while you must wait several months to sow seed after applying some weed killers, you only need to wait a few days after applying others. The reason for this difference lies in the effect of the active chemicals in the individual products. Read the label carefully and follow all the directions when applying a weed killer.
Sowing Seed After Applying Glyphosate
You can sow seeds in as little as a week or even sooner after spraying glyphosate, a systemic, nonselective weed killer. Glyphosate moves from the leaves to the roots of plants, destroying the entire plant, but leaving no residue in the soil. The chemical affects many types of plants, including weeds, grasses and desirable plants, but after the liquid is absorbed into the plant, it doesn’t pose any further threat. You can safely sow ornamental flower seeds a day after spraying with glyphosate and grass and vegetable seeds, three days after, even though the herbicide takes up to seven days to destroy weeds. If you remove the dying weeds too soon, live roots could remain in the soil, ready to regrow. Another systemic weed killer that doesn’t affect seeds is pelargonic acid.
Pre-Emergence Weed Killers and Sowing Seed
Pre-emergence weed killers prevent seeds from sprouting. They create a chemical barrier on the soil surface that suppresses seed development. What this means is, if you sow your own seed after applying a pre-emergence weed killer, the seed isn’t likely to grow. However, some pre-emergence products only affect grassy weeds, so you can safely sow most vegetable and flower seeds after applying these herbicides. The same doesn’t apply to reseeding or overseeding your lawn. Grass seed won’t sprout until a pre-emergence weed killer has decayed and become ineffective. For example, it isn’t safe to sow lawn seed until four months after applying a crabgrass preventer.
Sowing seed after applying a pre-emergence weed killer disturbs the chemical barrier on the soil surface, which means that weed seeds may germinate too.
Seed Sowing and Selective Weed Killers
Many selective weed killers leave little or no trace in the soil, and they target certain plants while leaving others unharmed. Generally, these types of herbicides destroy either grassy weeds or broadleaf weeds. You can safely sow most seeds in your vegetable or flower patch a day after applying selective herbicides, such as sethoxydim, clethodim and bentazon, for grassy weeds. These herbicides only affect your desired plants if the plants belong to the grass family. For lawns, herbicides that destroy broadleaf weeds are effective, but it isn’t safe to reseed until a month after applying these products, unless the label states differently.
- National Pesticide Information Center: Can I Plant Vegetables After Using a Weed Killer?
- Oregon State University: Top 10 Reasons Your Herbicide Failed
- Scotts: The Questions People Ask Most About Grass Seed
- The Center for Agriculture, Food and the Environment
- Roundup: When can I replant/reseed after use?
- The University of Tennessee Institute of Agriculture: Common Herbicides for Fruit and Vegetable Weed Control
- Roundup: How Soon Can I Replant After Using Roundup Weed & Grass Killer Products?
- Michigan State University Extension: Get an Early Start on Vegetable Garden Weed Control
A graduate of Leeds University, Jenny Green completed Master of Arts in English literature in 1998 and has been writing about gardening and homes since 2007. Green’s work appears in SFGate, Mom.me, The Pink Plumber and many home services blogs .