There are several things that might prevent mushrooms from growing on a typical timeline.
Air and moisture: First, it’s important to remember that to start growing, mushrooms need fresh air, water, and the correct temperature range. To ensure your kit is getting enough air, make sure that you have cut through a section of the plastic growing bag and that the growing media inside is exposed. If you have been covering your kit with a piece of plastic to prevent moisture loss, try taking this off. It is unlikely that your kit needs more water if it hasn’t yet started fruiting, but to make sure, you can weigh your kit to check for water loss. All kits should be between 5 and 6 lbs when new, so if yours is substantially less than 5 lbs you may wish to mist heavily and frequently or cover loosely with a sheet of plastic.
Temperature: All of our Grow-at-Home Kits should produce well at room temperature (20℃); if your fruiting environment is substantially warmer or colder, then this may be preventing growth. Also, if your growing environment is on the warm side, there are a few species that will need a cold shock before fruiting (shiitake and chestnut mushroom). To accomplish this, you can simply place your kit in the refrigerator (or outside if nighttime lows are below 10℃) for 24hrs, then return to the fruiting room.
Fruiting location: Another common issue is that your kit is fruiting, just not where you thought it would be. Examine all sides of your kit, and if you see mushrooms forming under the plastic at a site far away from your cut, simply make another cut to free the mushrooms you see.