how long does weed & feed last?

My husband used weed & feed on our lawn last spring. I want to try composting this year, but how long does the weed and feed stay on the lawn? I don't plan on using any dry grass from last year.

cabinfever wrote:My husband used weed & feed on our lawn last spring. I want to try composting this year, but how long does the weed and feed stay on the lawn? I don't plan on using any dry grass from last year.

My uneducated opinion is you are okay, my reasoning is that our garbage co. has a compost program from customer yardwaste (perhaps with some ammending to get the proper "composting ratio" (though that seems hotly up to interpretation as I have seen the numbers as high as a 20:1 all the way down to 1:1 ration greens to browns)) and it is certified to be used in organic gardening (OMRI certified) and you know there has to be weed and seed in their somewhere along the way.

I do not know. If I may suggest, you would probably get your answer from the manufacturer of the product you used last spring.

The first thing to realize is if the weed killer was still present, chances are your plants would not be able to survive. Very few plants can survive a weed killer chemical. Most likely, the fruit or vegetable plant you are growing is not resistant to weed killer. Many weed killers are designed to attack the plant’s root system. If weed killer was still present in the soil, you would not be able to grow anything.

Because of this fact, most weed killers are designed to evaporate within 24 to 78 hours. This means that for the most part, it is safe to plant anything, edible or non-edible, in a place where you have sprayed weed killer after 3 days. If you want to be extra sure, or you used a granular weed killer, you can wait a week before planting.

For, even if there are some residuals, these chemicals will have been leeched away after one or two good rainfalls or waterings.

For the most part, the chemicals found in weed killers are not a problem for the home gardener after they have evaporated or been diluted by rainfall. This being said, it is always a good idea to completely read the directions and warnings on the label of any weed killer products you buy. The manufacturer will have provided detailed instructions on how to apply the weed killer and when it will be safe to grow plants in that area again.