Problems occur mainly in wet summers, the foliage may only have started to turn yellow, but if left in wet ground too long the garlic will quickly become diseased. For this reason, there is a second method that can be used to determine which stage they have reached. In wet weather during early August, pull up just one bulb and see how many sheaths (the very thin paper-like layers around the bulb) you can peel off from the bulb - if there are only three then harvest the bulbs, if there are more than wait another two weeks, or until the foliage has turned brown.
When harvesting gently ease the garlic bulbs out of the ground, using a trowel to loosen the surrounding soil, although be careful not to bruise them with the trowel as they will not keep for long if this occurs.
The best garlic is fresh from the ground, as this is sweeter, less pungent and far more digestible than dried garlic. So to get the best out of your garlic you should use the cloves as soon as possible. However the majority can be washed, dried and than placed in a warm dry place in the garden (bring indoors in event of rain) to dry out; these bulbs will keep in good condition for 3 months or more.