I have seen mushroom growing kits in the UK before but this Christmas I was given a kit which was suitable as a gift since the marketing on the box was fun and smart.It was easy to use, simply cut a cross in the plastic area of the cardboard container and then spray with water each day. Success was guaranteed or a replacement box would be supplied.
In my case it only took 5 days before the mushrooms started to grow. Since the box was purchased in France the mushroom variety is Pleurotes jaunes, i.e. pleurotus or oyster mushrooms. Within 6 days we had 2 huge yellow oyster mushrooms which we cut and ate as in an omelette. They had a subtle nutty taste.
It seems that one of the mushroom reached maturity since we saw a lot of spores had flown around the box but fortunately I don’t seem to be allergic to spores.
My friend also bought a kit for herself (a pretapousser.fr box) and started hers at the same time as I did so that we could compare notes. Hers started to grow later but she had lots of small mushrooms. I don’t know what predetermines whether you get 2 big mushrooms or lot of small fungi but you do please let me know!