There are asparagus beds in England, and probably in this country, more than half a century old. It is not uncommon to find beds 20 to 30 years old producing profitable crops. In all such cases, however, there has been great reduction in the size of shoots and the crop is nearly always sold on local markets, which are not discriminating. After the plants are 8 to 10 years old, the size of the shoots diminishes rapidly, unless unusual conditions are provided. Fifteen years is the limit of satisfactory production in most large fields, and many growers prefer to destroy the old plants when they are 10 to 12 years of age. The field should be devoted to other crops for a year or two before replanting in asparagus.