Last year, for some strange reason, I had a lot of unwanted weeds growing in my garden. It was quite frustrating.
I got a generic weed killer spray from my local garden and sprayed it eagerly, hoping to create a clean slate for new grass. But, when I went to plant the grass seed, I wasn’t sure how long I needed to wait. I learned the hard way that timing is everything.
In this article, I’ll share what I discovered about waiting for the right moment to plant grass after using a weed killer. Let’s get into it!
What Factors Determine The Best Timing For Using Weed Killer?
The general consensus amongst experienced gardeners is that the best time to use a weed killer in the garden is when weeds are young and actively growing.
The optimal timing can depend on key factors like:
However, the amount of time you should wait before planting grass seed after applying weed killer mainly depends on the type of herbicide used. This is where the distinction between pre-emergent and post-emergent herbicides comes into play:
Post-Emergent Herbicides:
Post-emergent herbicides typically target actively growing weeds by taking a hit at their leaves, stems, or roots. While they don’t necessarily have an effect on weed seeds, they’re still incredibly effective at taking down established weeds.
These herbicides don’t have an impact on grass seeds either, but they can still harm new grass seedlings. To avoid interfering with the growth process of new grass, consider waiting 2 to 4 weeks before planting grass seed after applying a post-emergent weed killer.
Pre-Emergent Herbicides:
Pre-emergent herbicides, on the other hand, are made to break up the germination process of weed seeds by creating a barrier in the soil. They stop the formation of roots in germinating weed seeds, essentially holding them back from wild growth.
Unfortunately for all of you who are trying to grow grass seeds, pre-emergent herbicides can inhibit your germination and negatively affect the grass growing process. Thus, it’s best to wait a good 5 to 8 weeks after applying pre-emergent herbicides before you go about sowing your grass seeds into the ground.
Other Important Factors To Consider
Weather Conditions:
Waiting times for planting grass seeds can also depend on weather conditions. If the conditions are rather harsh with lots of strong wind or rain, the weed killer can dilute or wash off, potentially shortening the waiting period.
However, this isn’t ideal considering the weed killer washed off before it could have any meaningful effect on reducing weeds.
Soil Test:
If you’re unsure about how long you have to wait before sowing your grass seeds, a simple soil test can help with that.
The test can measure herbicide residue levels for you as well as other markers like pH and nutrient density, ensuring that the soil is safe and optimal for grass seed germination.
While it’s not “essential” or mandatory in any way, conducting a soil test can provide you with some peace of mind and give you a rough estimate to base your planting decisions around.
Final Words
After learning the hard way about timing, I gave my lawn the proper waiting period after applying weed killer.
The result? A bright and healthy garden that I can finally be proud of. All you need to do is make the right calls, be patient, and strategically use your tool (weed killer) to ensure your grass roots develop properly without hindrance from harsh substances.
