Rapini is ready to harvest when its buds have formed. In hot weather, check the plants daily, as the buds quickly open into flowers. Although still edible, once rapini flowers it becomes overly peppery and tough. Cut the main stem to between 10 and 15 centimetres above the coarser lower leaves. Each leaf node (where the leaves emerge from the stem) will produce another bud, so leave some on to enjoy a second crop. Individual buds can also be picked.
Store unwashed rapini in sealed plastic bags in the refrigerator for up to five days.
When to plant
Spring-sown crops should be planted so as to mature well before the heat of summer sets in; fall crops should be planted and harvested before frosts are severe. Use the maturity dates of each variety to calculate the best time to plant the seeds.
In spring, you also need to consider germinating periods; seeds will sprout within a temperature range of 4 to 35°C, taking about 14 days to germinate at 10°C, seven days at 20°C and four days at 26°C. Seedlings will survive light to moderate frosts.
Secrets to success
Growing rapini can be challenging, as the plants can bolt and become hot (overly peppery) and tough. Here are some strategies for success:
- Grow rapini in cool weather.
- Keep soil moist but not soggy.
- Keep plants well fed and thoroughly weeded.
- Plant several varieties to optimize chances of success. 'Sessantina', 'Sorrento', 'Spring Raab' and 'Zamboni' mature quickly and are usually dependable for spring planting, particularly for people having trouble with plants bolting.
To reduce problems with pests and disease:
- Plant in soil that hasn't been used to grow a member of the cabbage family in the last four to five years.
- Remove and destroy any diseased or infested plants; do not compost.
- Do a good fall cleanup by removing and composting dead plants.