A mushroom is mature and ready to be picked, when the thin veil covering the gills under the mushroom begins to tear open. To pick your mushrooms twist them a complete turn in place and slowly pull them out of the casing, trying not to disturb the adjacent mushrooms. Do not cut the mushrooms off inside the kit, as this leaves a stem in the casing to rot. In one to four weeks, depending on the variety and the temperature, another crop of mushrooms will usually appear. Be patient, repeat this process over and over again, until no further mushrooms grow.
Most kits produce two or more crops of mushrooms.
Water less after the second harvest, because fewer mushrooms will grow in the third and subsequent fruiting. The flies generally show up, if at all, heaviest towards the end of the kit's life. This acts as flypaper and the flies stick to it. Molds usually do little immediate harm and may be left alone, until you discard your kit. Just because a few contaminants show up, don't rush to discard your kit, wait a while to be sure no further mushrooms will grow.