The Grass Doctor

Will a pre-emergent weed killer kill new grass seeds?

i have to do some light/spot seeding but am worried that the pre emergent will kill the grass seeds? Is this the case? what's the best course of action? When should i put down what?

Public Comments

1. yes it will
2. wait till the grass is well established before putting weed emergent down weed emegent prevents weeds from starting but not existing ones any time now is good if you dont have weeds yet
3. Sadly, most pre-emergent will kill all sorts of grass seed (not just the weedy ones). I'm afraid there isn't much to do at this point, if you've applied the pre-emergent, you can't seed, and if you did seed, the product will kill the seeds. The direction I would give is , seed in the fall. Fall is a good time for lawn seeding. Becareful not to apply any weed killer to the young seedlings, as they can be damaged, but typically you don't need to apply any weed controls in the fall. Once upon a time, Greenview did make a 'smart bomb' Pre-emergent, which you could seed and apply. I don't remember the name of the product, and can't confirm that it is still available. It was much more expensive than the typical version available. I hope that this helps
4. Pre emerge chemicals prevent ANYTHING from emerging.Read the label for instruction on how to use.Don't put the P-E down before planting bare areas. Don't put it down on newly planted grass.Some grass seed will lie dormant for months before it sprouts so whatever you put down before the turf is well established will do more harm than good The chem. stops roots on the babies from developing somewhat
5. Most kinds of pre-emergent weed killer work by stopping weed seeds from germinating, and they can also stop grass seed from germinating. The kind of weed and feed I use contains a pre-emergent, but that's OK because I don't plan to overseed until about a month and a half after I applied the chemical. Just check the back of the bag. Mine says it will be OK to seed the lawn in about four weeks, but I plan to wait even longer than that.
6. Pre-emergent is designed to keep seeds from germinating, so it is not the right course of action. Wait until the grass is established before using any weed control.