Radicchio (Cichorium intybus)
Technically belonging to the Chicory family, Radicchio is a quick growing bitter red leafy vegetable.
How to Grow Radicchio from Seed
Radicchio is a very easy-to-grow lightly frost-tolerant annual that grows best in full sun, but will tolerate part shade. Pick a spot that receives at least 5 hours of sun a day. Radicchio greens grow most successfully in well-drained soil that is both rich in nutrients and moist.
Most Radicchio germinates poorly in hot weather and bolts quickly, so be sure to plant in early spring, late summer or early fall. Succession plantings every two to three weeks are recommended for a continual harvest through the fall. Plant Seeds: 1/8"deep with 1/2" between seeds and 12" between rows. Plant several seeds in each hole. Thoroughly water seeds after planting. Continually water lettuce daily to keep soil moist. As seedlings emerge, thin them 6-10” apart for mature heads or do not thin for baby leaves. Seeds will sprout in 3-15 days.
Baby Radicchio leaves are ready to harvest in about 24 days. Days to maturity for heads will vary depending on the variety. Harvest above growth point for cut-and-come-again production or cut lettuce at soil line with a knife for single harvest.
How to Save Radiccho Seeds
When planning to save Radicchio seed, plant a little more than what you need for harvesting to eat, and don't harvest any leaves from these plants. Late spring is a good time, you want good plant production, but close enough to the heat of summer for the plants to bolt and send up flowers. Save seeds from vigorous plants, but avoid plants that are the first to bolt-- otherwise you'll be selecting for a tendency to bolt early. Radicchio seeds don't have a protective covering, so disease can develop quickly and infect the seed in wet conditions. Disease organisms can also carry over on the seed. When your Radicchio plants are flowering, watch the forecasts for rain and harvest early if needed. You can harvest as early as two weeks after the flowers open. You can pull the whole plant, roots and all and allow it to dry upside down in a well-ventilated area protected from the elements for further seed development. You can also cut the seed stalks off as they mature and place them in a paper bag for drying.
If you don't need to collect large quantities of seed, you can pull off the individual white tufts, to which the seeds are attached. Put the tufts into an envelope or jar so you won't lose the tiny seeds.
To clean the seeds, shake the seed heads into a large bowl or bag to loosen the seed. The seeds are small and light, just barely heavier than the chaff so the best way to clean them for long term storage is to rub them through seed screens. The right size will have the chaff fall through and the seeds will stay on top. If you are only storing until the following season, you can probably get away with storing your seeds with the fluff, and just planting the seeds and fluff together the next year.