10g (0.35oz.) biologically dried mycelium on grain seeds, ready for growing outdoor in a non-sterile environment. 1 packet is recommended for a mushroom bed of 80x80cm (30x30 in.) Edible mushroom. Slippery Jack Mushrooms are wild mushrooms that grow in symbiotic relationship with pine and spruce trees. They grow from mid-summer to early autumn. The caps are saffron colored or yellowish-brown, though they can be a dark chestnut brown. As the mushroom ages, the cap flattens. The cap can be anywhere from 5-13 cm (2-5 in.). Under the cap, there are pores instead of gills. The stalk of the mushroom ranges from 2.5-7.5 cm (1-3 in.).