I just broadcast some 2, 4d amine weed killer and was planning to aerate and overseed in the near future.

How long after applying the 2,4d amine weed killer is it advisable to overseed?

  • What are you overseeding with? If it includes clovers or any other broadleaf plant the answer will be very different from pure grass seed.
    – GardenerJ
    Commented Sep 10, 2015 at 14:27
  • Thanks for the reply! I'm planning on using 100% grass seed; some sort of sun / shade mix. Commented Sep 10, 2015 at 18:36
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    Re-entry, re-planting should be on the label of this herbicide!! Get on the internet of this brand and they should be able to provide the instruction/information sheet as well as the manufacturer's MSGS notes. Think Kevinsky has provided this in his FACTS attachment. Before using ANY chemical other than water, please read the instructions (they say 5X) before applying! Grins...sure helps to not make mistakes you'll regret...
    – stormy
    Commented Sep 10, 2015 at 20:21

1 Answer 1


This reference claims that

The degradation of 2,4-D is rapid (half life of 6.2 days) in aerobic mineral soils

This reference claims

Most of the time, 2,4-D breaks down in soil so that half of the original amount is gone in 1-14 days.

If you follow the references it is very difficult to find a clear statement of how long it lingers. Note the reference to aerobic mineral soils which also imply a reasonable level of organic matter and consequent microbial activity. In other words it will break down faster in a healthy soil than a dry impoverished soil.

Also keep in mind that 2,4 D is rarely sold without other chemicals added to the mixture and even the ingredients that are considered "inert" which can be 85% of the mixture can change how long it remains active.

When I was a landscaper and my money was on the line I would not over seed for at least four weeks. Grass seed is not as cheap as it was and customers have little tolerance for seed failing to germinate.

This fact sheet makes for thoughtful reading.

  • Great fact sheet, Kevinsky...this is also part of the old Caseron to inhibit growth of seeds and has little effect on grass type weeds. Boy, I don't think new grass seeds will be very vigorously germinating for quite awhile! Ugh!! I thought this stuff was banned from commercial applications, definitely homeowners. I do know that they've made GMO plants that INCORPORATE this IN THE PLANT. Ugh. Again...what do you think?
    – stormy
    Commented Sep 10, 2015 at 20:30
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    Your answer jives with docs on the bottle. Bottle claims that you can seed after 2 weeks at 1.5x the seed density recommended by the seed manufacturer. I recognize that RTFM is a thing but I wanted to get some observations by those who have practical experience. Thanks! Commented Sep 11, 2015 at 13:58

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