Radishes grow best in the spring or late summer. They do not like hot weather. For quality yields, radishes should be grown rapidly with plenty of moisture. Approximately 80 seeds/gram.
Hints:

Sow seed 1 cm apart and 1 cm deep in rows 30 cm apart.

Thin to 2 to 4 cm apart.

Sow several times at weekly intervals until early summer for a contiuous fresh supply.

Try sowing with other vegetables to help mark row.

Long Black Spanish - 56 days. Winter variety. Roots are round, inclined to top shape and are 8-10 cm [3-4"] in diameter. Nearly black in colour with crisp white flesh. Good for storing.