You can recognize fresh rockets by the leaves: are they juicy, crunchy, and nice and green? Then the salad is fresh and you can buy it without hesitation. Yellowish or withered, limp leaves, on the other hand, show that the rocket is a bit older. So that the delicate rocket is not crushed, you should carry it at the top of the shopping bag.
Unfortunately, the arugula, as the rocket is called in German, does not last long. It is best to use them fresh. If you do need to store them for a day or two, then pack them in an airtight storage bag or wrap them in a damp cloth in the vegetable compartment of the refrigerator. You cannot freeze arugula as the leaves become mushy when thawed and lose their flavor.
Rocket is produced in Germany from spring to autumn, mostly harvested by hand or by machine. In the winter months, the rocket usually comes from Italy. Here production takes place in foil tunnels, which means that the Italian rocket usually has smaller leaves and is less intensely green in colour.