Depending on the period of culture, the length of the cycle and the characteristics of the root, radishes are grouped as follows:
- Year-round varieties: Small roots and very short cycle (4 weeks). There are rounded, half-rounded, semi-large and large roots.
- Summer-autumn varieties: With more voluminous roots and somewhat longer cycle (6 weeks).
- Winter varieties: Large roots and very long cycle (up to 100 days).

In countries with harsh winters, the cultivars of small radish or radish are grouped in: outdoor spring culture, outdoor summer culture, outdoor autumn culture and greenhouse culture.

In Spain, the most recommendable varieties for culture are:
- Summer radishes: " Fluo’ with soft and cylindrical roots, bright red colour and white tips. "French Breakfast" with classic cylindrical, soft and sweet roots. "Ribella’ with round roots, taking quite a long time to develop.
- Japanese or "Mooli’ radishes: "April Cross" with roots longer than 30 cm; it bears the winter very well. "Mino Early" is a very popular and soft variety.
- Winter radishes: "Black Spanish" is a very old variety that may be round or elongate. "Cherokee’ has round roots resembling a cricket ball. "Chinese Rose’ is a variety with red long roots and white pulp. The "Mantanghong" roots are as big as a tennis ball, with a white-greenish skin and red-purple pulp.

Another classification for radishes, this time botanical, according to Liebster (1990) is:
- R. sativus var. sativus: It includes those cultivars of small size, elongate or rounded, white, pink or red.
- R. sativus var. niger: Cultivars with a larger hypocotil, usually elongate and white or red, although there are also black and rounded cultivars.
- R. sativus var. longipinnatus: Grown in the Southeast of Asia. These hybrids are characterized by a long and thick hypocotil (30-50 cm). They have a smoother taste than the previous group and they are also called ‘Daikon radishes".

The term "radish’ includes the cultivars previously classified by Liebster (1990). The use of the terms "little radish’ and "radish’ is very common. The "little radishes’ correspond to the botanical classification Raphanus sativus var. radicul and R. sativus var. sativus; they are characterized by their small size and the short vegetative cycle. On the other hand, "radishes’ belong to the botanical classification Raphanus sativus var. niger and have a longer vegetative cycle than that of "little radishes’. Another difference between them is that the edible part of "little radishes’ is only formed by the hypocotil, whereas "radishes’ include elements of the base of the chief bud and the root.