The quickest, easiest, most reliable mushroom kits we’ve ever seen! With these handy kits you’ll soon be picking delicious fresh mushrooms straight from the windowsill, at a fraction of the cost of buying them at the supermarket. Kits comprise base tray, lid, and pre-spawned substrate. White Button Mushroom Kit - Traditional, versatile, tasty white button mushrooms. Note: cariage charge £4.99.