When to Plant Radishes

Botanical Name: Raphanus sativus

Radishes do best when grown from seed in the cooler seasons of the year. Cool soil = good growth.

The hardy radish seeds are amazingly quick to mature to eating size – sometimes in three weeks, depending on the variety. You can plant radish seeds and often see the first growth in just five days!

Seeds for these fast-maturing table radishes should be sown a little bit at a time in succession over the course of a month or two, beginning in the earliest spring, with a second planting again at the end of summer. That way you don’t end up with too many to use at once. Radishes left in the ground to grow too long can become woody and bitter, while tender young radishes taste crisp and light.

On the other hand, there are a relatively few radish varieties that take much longer to mature.These should be planted mostly in the late spring, to mature anytime from late summer to early winter. Seed catalogs and seed packets are indispensable tools in determining which kinds are which.

Depending on where you live and garden, the term “cool soil” can mean any month from
February through June, or August through November! Southern gardeners have much more latitude in planting, and gardeners in cold northern climates will have just a few months to plant.

With careful planning and planting, gardeners can have two lengthy harvests of radishes in a year, and the growing season gets even longer when it includes some of the more heat-tolerant varieties.

So radish season is a highly local affair…at least if you hope to harvest crunchy and not too spicy radishes. Here is some more detailed information about when to plant radishes:

• For the fastest growing radishes, which mature in about three weeks, plant the first seeds once the worst of winter weather is over, and continue planting every week or so until about June.
• Make the second planting when the summer’s heat and most intense sunlight begin to fade, say, in mid to late August.
• For certain types of radishes the maturity ranges from 50-120 days rather than the more common 20-45 days. These radishes should be planted in late spring, say, before the end of June. They will mature sometime in the autumn, and most can be left in the ground past the first frost.
• Be sure to utilize seed catalogs or read packets for the days to maturity…and plant accordingly. Such resources tell gardeners just how long it takes for radishes to grow.
• For the radishes that do best in mid-summer heat – and there are some — key words to look for include “slow to bolt” and “resists pithiness.”

The wonderful world of radishes holds a staggering array of seeds for all possible growing conditions.