Detailed Explanation of Key Cultivation Techniques for Radicchio (Red Chicory)

1) Varieties. Radicchio has many varieties in Europe, and their colors and shapes vary greatly. We have introduced conventional varieties and F1 hybrid varieties from the Netherlands and France, but have not yet selected a variety suitable for spring and summer cultivation, and the seed purity is poor, which greatly affects yield. Through trial planting, Beacon from Bejo in the Netherlands performed somewhat better. The Beacon variety grows relatively uniformly, with green outer leaves, red round heads, white leaf veins, and an attractive head shape, and it has a certain tolerance to bolting.

2) Land preparation, fertilization, and bed making. Radicchio is not strict about soil requirements and has moderate fertilizer needs. It is advisable to apply 45000 kg of decomposed organic fertilizer per hectare, along with 750 kg of compound fertilizer. Level the entire plot, and make flat beds 1.33 m wide; plastic film mulching can also be used, with flat-raised beds under drip irrigation.

3) Seedling raising. ① Sowing period. For summer and autumn cultivation in the Beijing area, sowing is generally done in mid-to-late June. Under suitable conditions, radicchio generally begins to be harvested about 100 days after sowing, and because growth is uneven, the entire growing period is 120-130 days. In northern regions, if harvesting is needed before the Spring Festival, sowing must be done in early to mid-August. When the temperature is suitable, the seedling age is about 30 days. If the temperature during the seedling period is low, a small arch tunnel should be added inside a solar greenhouse. ② Seedling raising method. If conditions permit, plug tray seedling raising can be used, generally with 128-cell plug trays, or flat-bed broadcast sowing can also be used for seedling raising. ③ Transplanting and transplanting density. Generally, when the seedlings grow to 5-7 leaves, they can be transplanted. The transplanting plant and row spacing varies depending on the variety and planting season. For early-maturing varieties, the transplanting plant and row spacing is about 0.33 m, while for mid-to-late-maturing varieties, the transplanting plant and row spacing should be no less than 0.4-0.5 m. For autumn planting, because conditions are suitable and the plants grow full, they should be planted sparsely; spring and summer planting should be denser than autumn planting; for winter greenhouse cultivation in the north, the density should be appropriately increased. ④ Management after transplanting. Radicchio management is relatively simple. After transplanting, water with transplanting water; after 5-7 days, water with recovery water; after the recovery water, cultivate and weed once to promote leaf growth during the rosette stage, and apply a topdressing of nitrogen fertilizer once, with 150 kg of urea per hectare. During the heading stage, water and fertilizer should be increased, with watering and fertilizing once every 5-10 days, depending on weather conditions. Later topdressing should be applied at a ratio of nitrogen:phosphorus:potassium = 1:0:2.