What is an effective pre-emergent herbicide for lawns?
Choosing the right pre-emergent requires knowing exact product names and strict application timing relative to when you seed. Without clear notes, homeowners miss their narrow seasonal windows and struggle to figure out whether to spray products like Tenacity before or after laying new seeds and soil.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
- 1Applying Hi-Yield Weed & Grass Stopper with Dithiopyr despite warnings that it will be minimally effective
- 2Considering multiple applications of the pre-emergent product
- 3going with Scott's triple action built for seedling
- 4setting up sprinkler systems ahead of seeding to test connections
- 5Searching online for conflicting application guidelines
- 6Applying mesotrione at seeding time
- 7Applying Scott's starter granular fertilizer with mesotrione at the same time as seeding.
In their words
Unedited, most upvoted first, each linked to the thread it came from.
“pre emergent - this is where I need advice. Before nuking the lawn, I had : crab, dallis and clover galore.”source ↗
“Given that the seeds live in the dirt below, should I apply Tenacity before i even put down the seed? Or spray it over the top of everything after I've laid down the seed & soil?”source ↗
“I had my calendar marked to put down pre-emergent last weekend but my notes didn't specify which pre-emergent.”source ↗
“What else should I be looking at as an effective pre-emergent?”source ↗
“Was just wondering because I see tenacity recommended here for pretty much every new lawn seeding post.”source ↗
“My question is if you nuke your lawn/weeds with glysophate 2-4 weeks prior and then you seed after, do you need to apply tenacity in this situation or is the glysophate that was put down weeks prior already preventing new weeds from sprouting?”source ↗
“When should you do Tenacity in relation to over seeding?”source ↗
“I am wondering if I can apply Prodiamine 65 WDG 30 days after seedling (so in another 2 weeks) in order to have continuing pre-emergent coverage on POA Annual?”source ↗
“Online search results on this subject is mixed but I don't think I can re-apply Mesotrione to an area with newly geminated tall fescue neither. What's my best option here?”source ↗
Where this came up
People with this problem also raised
- 50How to get rid of creeping weeds without breaking roots
- 10Should I kill crabgrass in late summer or wait for spring?
- 20How do I figure out what kind of grass I have?
- 2Is it safe for pets to walk on treated grass?
- 5Are later steps in lawn care programs actually necessary?
- 2Why is green growth showing up so fast after seeding?