Answer: According to John Hart, soil scientist with the Oregon State University Extension Service, Mushroom compost can supply nutrients and increase the water-holding capacity of the soil. But mushroom compost can be too much of a good thing for seeds, seedlings and young plants. The soluble salts and other nutrients in fresh, undiluted mushroom compost are too concentrated for germinating seeds, young plants and other salt-sensitive plants. To avoid killing germinating seeds and stressing young plants we recommend mixing mushroom compost with garden soil. Or, order a supply of mushroom compost in the fall and let it sit uncovered, to "cure" over the winter.
Q&A Library Searching Tips