Add water until it drips from the wick, then place the can on capillary matting reservoir, under a light bank. After 4 - 5 days, thin to one healthy seedling. After 16 - 20 days harvest your radishes. Investigations with the common or garden radish, Raphanus sativus Packets of radish seed are inexpensive and widely available. Several different varieties are sold, so comparisons can be made between them.
Radishes grow well in film cans on capillary matting under a light-bank.
The nutrient regime can easily be controlled. The plants are small and compact - many can be grown in a small space. After 2 - 3 weeks there is a recognisable crop. The crop can be measured in a variety of different ways. In a given packet, the seed will be genetically uniform.