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Radishes can become strongerRadishes can become stronger in flavor and pithy in warmer temperatures. With the longer daylength and warmer temperatures, they also bolt (send up a flower stalk) faster; in this case, the growth of the radish root slows. Radish plants like air temperatures between 50 and 65, ideally. Some cultivars are more heat tolerant. Perhaps the best you can do is try to keep them cool; use row covers or similar during the hottest part of the day. Keep the soil consistently moist (not soggy). Be sure to thin them to recommended spacing so as not to stress the plants with overcrowding (pinch seedlings off at the base, rather than pulling them up). A Kansas Cooperative Extension article recommends planting in mid- to late March and early September, so if this crop doesn't fair well, you'll at least have another opportunity for a fall crop.

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