mushrooms growing in aged manure

Asked May 8, 2017, 11:13 PM EDT

we acquired aged horse manure + bedding free from a neighbor farmer and was told that it had sat for 8 months. we layered this with decomposing wood matter from the forest, finished compost and potting soil last winter into garden beds and now these 48 garden beds are growing at least 7 or 8 different types of mushrooms. one looks like a light brown morel. one is iridescent brownish gold. one almost looks like large clusters of button mushrooms. is this bad? we are having troubles with pest and our seedlings are getting super eaten and looking very unhealthy. any ideas of what we can do to turn it around? the soil is testing as nitrogen deficient so we are thinking of adding rinsed coffee grounds.

Clackamas County Oregon

1 Response

Hello, based on the description of your compost feedstock, my guess is that your plants are probably suffering from N deficiency. I doubt those feedstocks contain pathogens for vegetable crops. Coffee grounds have roughly 2% total N. Not really enough to mineralize very much N. If you are seeing N deficiency symptoms, I would recommend side-dressing with feather meal, blood meal or a similar product with about 12% total N. You could also use synthetic N fertilizers like urea unless you are gardening organically.

It's difficult to recommend specific rates without more information about your soil and your crops. You could use the OSU Organic Fertilizer and Cover Crop Calculator to predict PAN release from fertilizers.

This is a long shot, but you might want to ask your neighbor if there's any chance Stinger herbicide was used in the pasture or to grow hay for their horses. These residues can stick around through the manure and composting process, and effect subsequent vegetables.

Feel free to call me at 503-913-9410.
I hope this helps.