Asked August 23, 2016, 4:23 PM EDT

I added about 2 cu yards of well rotten horse manure to a small garden 3 years ago. It was contaminated with aminopryalid. I keep hoping each season will be better, but I have almost no fruit on the plants, and stunted, curled growth. I have mixed my home made compost in the planting beds, but it didn't help much. I read that aminopyralid will start breaking down in 35 days? I'm at the end of the third year and wonder if I should bother next year? How do I get rid of this poison? I am so discouraged. I know that you are an Oregon site, but the problem is here too.

Nevada County California plant disease

3 Responses

Your best bet for local advice is to contact your county Cooperative Extension Master Gardeners. Their contact information is at

I had already contacted the local master gardeners. They knew nothing about aminopryralid and the damage it causes. Do you know of any other experts I could get information from about this herbicide?

We sympathize with you. In Maryland, we have seen injury to vegetable crops up to 2 years after application of contaminated manure, compost, or hay to soil.

The herbicide residues will eventually breakdown, though we're surprised it's not happened by now.

Hopefully you have an alternative location or can switch to containers for awhile. You can "test" your raised bed soil periodically by planting some pea or bean seeds periodically and observing germination and plant growth.

Short article from our website and links to more info: