Hello, We received some soil from a farmer friend recently in which we intend to plant several species of annual flowers. The soil was treated with pendamethalin. Would you recommend planting into this soil treated with this particular herbicide? Does it matter how long ago the application occured?

Thanks Robinette

Hi,

Pendamethalin is part of a class of herbicides called dinitroanalines. They are effective as a preemergent herbicide especially for grasses and some broadleaf weeds. It has the potential of remaining in the soil for about 4-6 months which means it may affect the growth and development of young seedlings by damaging the roots. The breakdown is affected by time and moisture in the soil and temperatures. If you are planting annuals you may not see any affect especially if the material was applied early and has had a chance to degrade. To be certain that there is no chemical present you might want to take some of the soil and put it into a pot and then sow some grass seed on the soil and see if it affects the germination of the seed. If you see no affects nd the grass grows normally then more than likely the chemical is no longer effective and should be okay to plant other things into the soil.