Radish 'Sparkler'

Once your radishes germinate, keep them watered as evenly as possible. Do not over water, but don’t let them dry out either.
Thin out the seedlings to give enough room for the root to grow

Position in a full sun location and remember to water moderately. Keep in mind when planting that Sparkler is thought of as half hardy, so remember to protect this plant from frosts and low temperatures. Sparkler requires a loamy, clay and sandy soil with a ph of 5.5 - 6.8 - it grows best in weakly acidic soil.

Sow in stone-free soil in early spring to early summer, and again in late summer for fall crop (if desired). Thrives in cool weather. Make successive sowings every 2 weeks. The recommendation for most root radishes is to directly sow them 4 weeks prior to your last frost date. However, you can start sowing as soon as the ground has thawed and air temperatures are averaging over 40 degrees on most days. Depending on what your springs are like (short and fast, long and drawn out), these conditions may emerge much sooner than or much later than the 4 week guide might suggest. Don’t be afraid to experiment.

Try to aim for a seed spacing of at least 0.98 inches (2.5 cm) and sow at a depth of around 0.47 inches (1.2 cm). Soil temperature should be kept higher than 13°C / 55°F to ensure good germination.

By our calculations, you should look at sowing Sparkler about 28 days before your last frost date.

Do not transplant, the root will not develop correctly. For Square Foot gardens, these are planted 16 per sq. ft…trust me, you can actually fit that many.

Ensure that temperatures are mild (minimum night temperatures should be around 10°C / 50°F) and all chance of frost has passed before planting out, as Sparkler is a half hardy plant.

Harvest as soon as the root is large enough to use, older radish easily grow tough and woody and run to seed

Expect harvests to start to occur in early spring.