To harvest asparagus you will need a knife. This is because you should not pull the spears or snap them off but cut them approx 10 cms below the soil surface. You can buy special knives however a sharp garden or kitchen knife will do. The spears will start to show sometime in April and are ready to start gathering when they get to 15cm long. Leave them any longer, the fern will start to shoot out and the spear will no longer be edible. You will get a gradual increase in new shoots over the first 2 weeks so to start with you may have enough to create a starter you all fight over and by mid season have enough to make a meal of. Unlike commercially grown varieties supplied to the supermarket, home grown asparagus will often arrive in the kitchen a variety of lengths and diameters, it is not always straight either. This isn't a problem in our household as it all tastes delicious, if you want uniformity you had best not grow your own.
The rule of thumb when considering whether to stop cutting and allow the plant to rejuvenate is don’t cut beyond the end of May. In a low yield year this could be earlier. Over cutting will exhaust the plants and lead to poor cropping next season.
Storing your harvest
Asparagus does not store well and it is not advisable to leave the spears in the ground after they reach their ideal cropping height either. If you can't use it the day you crop, your asparagus will keep in the refrigerator for up to a week. The flavour will start to decline over time and the spears become soft. It can be frozen successfully but will lose its firm texture.
To freeze - Wash and separate the thick and thin stems. Bundle the stems and blanch in a steamer or asparagus pan of boiling water, the thin ones for 2 mins the thick for 4 mins then freeze them in a rigid container.
Pickles and chutneys - perfectly possible but best eaten fresh Canned - perfectly possible and available in supermarkets, tends to be sloppy and the flavour is unpleasant, I'll leave the experts to it
Dried - again possible if freeze dried, I am not going there.