Leaf Mustard 'Red Giant' is an Asian leaf vegetable from the mustard family. This variety forms a loose crop with nicely red-green, somewhat ribbed, round leaves and a spicy taste. It is also known as mustard lettuce, mustard cabbage or cabbage leaf. It is susceptible for clubroot, so crop rotation is important. It can withstand frost very well, and it is a fast grower (can be harvest 5 weeks after sowing already) and can be harvested for a long period.
Mustard grows best in a sunny position in a fertile soil. It can be sown directly into open ground or can be planted into grow bags. If grown for babyleaf it can be sown into small containers or even windowboxes. Choose a well-drained container that's at least 10 to 15cm (4 to 6in) deep. Containers may need to be watered a couple times a day when temperatures begin to warm. If growing micro-greens, seeds can be planted in shallow flats and harvested about 10 to 21 days after planting. If given adequate light, they can also be grown indoors during the winter.
Sowing: Sow under cover February to May or sow direct April to October
Mustard seeds can be sown practically year round. Plant little and often, every two weeks for continuous supply. Seeds germinate in 5 to 10 days at temperatures between 7 to 30°C (45 to 85°F)
Sow sparingly in shallow drills 6 to 12mm (¼ to ½ in) deep. Space seeds 2.5cm (1in) apart for cut-and-come-again salad or 20 to 25cm (8 to 10in) for whole plant production. Adequate spacing is most important when growing plants to full size. This is easy to accomplish by simply thinning plants as they begin to get crowded in the garden.
Mustard greens are primarily a cool season vegetable and are at their peak in late spring to early summer. Keep well watered especially in summer. Hot weather causes the plants to bolt and their greens to turn unpleasantly bitter.
An autumn crop is often planted because mustard is frost-resistant and easily overwinters in temperate areas. Protect late sowings with cloches and the plants will keep growing throughout the winter and continue to grow vigorously when temperatures warm and daylight increases.
Harvesting: 20 days for babyleaf, 45 days to maturity
Mustard plants can be harvested for baby leaf once the leaves are 5cm (2in) tall. For milder leaves, pick young, they are best cropped at around 15cm (6in) for salads.
The plants will grow to around 30 to 45cm (12 to 18in) tall. Mature leaves can be boiled or steamed or braised in a pot with a little butter and garlic.
Use scissors or a knife rather than pulling the leaves to avoid damaging the plant. Keep picking regularly to prevent flowers running to seed. Pull and compost the plants once hot weather arrives in the summer, as mustard greens become tough and bitter.