Summer Squash: pick when small, if fruit gets big the plant stops producing. Check the plants regularly!
 
Winter Squash: Fruit is ripe if your thumbnail doesn't mark the skin and the stem is dry and brown. Cut the stem about 4cm (2") from the fruit. Squash survive a light frost, but store better if harvested before frost.
 
Storage: Field-cure for 10 days in the sun, or cure indoors in a warm room for 4 or 5 days. To prevent mould sponge the skins with a solution of 10 parts water to 1 part chlorine bleach. Store at 10-15ºC (50-60ºF) with low humidity with good air circulation. Try on a shelf in the garage.