Will rain wash away my weed killer?
Whether applying weed killer on a sunny day or having a commercial service spray during a drizzle, people worry that subsequent rain will ruin the treatment before it dries. This unpredictable weather leads to varied results over the years, leaving them guessing if the application will actually work or if it won't.
What the numbers show
Counted from the threads quoted below. How we count
- People have been saying this in most months since September 2026.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
Will rain wash away my weed killer?
- 1Waiting a few days to see if weeds die and examining themDid this help you?
- 2Checking if a surfactant was usedDid this help you?
- 3Avoiding watering or cutting the grass for at least 24 hours after applicationDid this help you?
- 4Checking the weather forecast carefully before sprayingDid this help you?
- 5Waiting several months before pressure washing the house to avoid stripping the residual pesticideDid this help you?
- 6Focusing on just thinning the pest herd rather than expecting 100% elimination if rain is a factorDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“So our commercial lawn service sprayed our lawn the other morning while it was drizzling. Then the following day it rained about 1/4”. Nothing ever dried and it’s still raining off and on.”source ↗
“Does rain have an effect on this service?”source ↗
“Ive had varied results over the years. Sometimes it works, sometimes it doesn't.”source ↗
“Asking becasue I sprayed yesterday when it was sunny and relatively warm. Forgot to check the weather.(last rain here was almost 4 weeks ago) Weather forecast now says my area is supposed to receive "historic, record-breaking" amounts of rain in the next 2 days. :(”source ↗
Where this came up
People with this problem also raised
- 2Why does a low flow weed sprayer take forever to use?
- 20When can I put weed killer down after overseeding?
- 20Will heavy rain wash away grass seed after overseeding?
- 3How to kill weeds in flowerbeds without killing plants
- 3How to establish a lawn without germinating weed seeds
- 3Is indoor pest control spray safe for humans?