Radicchio leaves can become very bitter and inedible, but there are some simple growing tips that should prevent this:
1. Grow as a cool-season veggie: This is because the bitterness of the leaves increases in hot weather. Sow seed in autumn so that seedlings are well established by June. Plants are frost tolerant, and cold weather helps to sweeten the flavour and turns the leaves from green to wine-red.2. Plant in fertile, well-composted soil: Radicchio3. Don’t neglect watering: Weekly deep watering prevents the leaves from becoming bitter. Infrequent watering that allows the soil to dry out increases the bitterness of the leaves and results in poor, uneven growth.4. Feed regularly with a liquid plant food once the seedlings are planted out, but avoid nitrogen-based fertilisers. (They cause the plants to bolt and the leaves become inedible.) A liquid drench or foliar food like EcoBuz MultiGro contains a balance of macro- and micronutrients. To apply as a drench, mix 5ml with 5 litres of water in a watering can or 5ml per 1-litre in a spray.5. Ensure tender, tasty heads by watering well 10 days before the heads mature. This is regarded as the most critical watering period.6. Harvesting: Pick the outer leaves as needed, when young and tender. Let the heads develop until they are firm, about 60 days after planting. Don’t leave them too long or they become bitter with a hard core. The heads regenerate if cut off carefully just above ground level and they may produce a second harvest.
