Posted by Ken on 8/31/2006, 10:49 am, in reply to "Mushroom compost" Be very careful with mushroom compost - it's ubiquitous and reasonably priced, however there is no strict definition of "Mushroom Compost" so you never know its composition or what's been done to it. Apparently, mushrooms will grow on just about anything as long as it's dark and moist. I grow containerized daylilies, and a few years ago I bought a yard of "container mix" from a local topsoil yard. I have patronized this establishment for many years, and they are a highly-regarded "organic" business with a very good reputation. Everything I planted in that batch of soil declined over the course of the summer. The plants always looked as if they needed more water, even though they were soaked regularly. When I repotted the plants in the fall, a significant chlorine odor was apparent in the containers - as if the irrigation water had been over-chlorinated. The normally white and tan fleshy roots of the plants were dark orange and brown, covered with pustules and (for lack of a better term) "open sores". When I asked the people at the topsoil yard about it, they admitted that they had been made aware of the problem by several customers, and that it had been traced to a mushroom grower who was using Clorox to sterilize his compost. I don't know if that was true or not, but the lesson was learned. I have also had commercial bagged potting soils containing mushroom compost do odd things, such as becoming overgrown with a mycelium which renders the soil water-repellent, leading to the decline of the plants. The majority of mushroom compost might be OK, but these are some things you should be aware of. I don't think it's worth risking valuable plants to a soil component of such high variability and unknown provenance. Many of the materials used in mushroom compost are not even composted - they are still raw, and will break down in use, which I believe contributes to the same mycelium overgrowth I mentioned before. Daylilies are the one of the toughest container subjects I grow, and I grow a wide variety of plants. If something will damage a crop of daylilies like that, it will simply kill anything else. I also had a bad experience when using red lava rock as a cheap substitute for pumice. Since then, I have been advised by soil "experts" that many plants will not tolerate the toxic levels of free iron and other minerals it releases. Black lava rock seems to be fine. Ken
71.131.49.149
Lori,
East SF Bay Area
USDA Zone 9
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