I built a planter box out of rosewood (3' x 1' x 1'), and have 1 row of tomato plants (3) and 1 row of lettuce (6), each started from seeds. Used organic potting soil and no fertilizers. A few weeks in, some mushrooms started to appear. I'm told this is a good sign of healthy soil and biodiversity. However, they are now coming at rapid rates and release black, gewy ink onto the leaves of the baby plants. I'm concerned that they will interfere with the health of the vegetables if they don't slow down. Is there anything I can introduce into the soil that will slow down/eliminate the mushrooms (sans chemicals)?