Rock cress 'Harknoll Red'

Keep in mind when planting that Harknoll Red is thought of as hardy, so it can be safe to leave outdoors for the majority of winter (although if in doubt, using a row cover is often a good idea).

Soil temperature should be kept higher than 10°C / 50°F to ensure good germination.

As Harknoll Red is hardy, ensure temperatures are mild enough to plant out - wait until after your last frost date to be on the safe side.