Crispy head lettuce. Crunchy lettuce is slightly different from butter lettuce. Creates very large heads, hard, with a diameter from 15 do 20 cm, weighing from 700 do 1000 g, with round leaves, in the shape of an oyster shell – due to strong, arcuate curve of the main nerve. The leaves are more or less curled, clear- or dark green, firm, brittle, juicy, tasty, with high nutritional value (minerals, especially calcium, iron and vitamin A., B„ B2, C, E). Shortcrust lettuce is prepared and served like butter lettuce and can be added to sandwiches and multi-vegetable salads.. Crunchy lettuce, just like butter lettuce, it is a plant of a cool climate. The optimum temperature for its growth is around 15 ° C. High temperature causes premature killing of plants into inflorescence shoots, lettuce bitter, and also its rotting. This lettuce requires a moderate amount of soil moisture. In early spring, it should be grown in clay-sandy soils, slightly heavier and peaty soils are more suitable for later cultivation. Due to the poorly developed root system of lettuce, the soil for its cultivation must be sufficiently moist and airy. Crumbly lettuce is sensitive to soil acidification, therefore, the best for her is the neutral reaction of the soil. The soil for crumbly lettuce should be plump. It should be well prepared – dig deep in the fall, and in spring, smoothen and break up the lumps. Growing crispy lettuce in addition to organic fertilizers, given in the fall (4 kg / m2 of manure), mineral fertilization is applied in quantity: 20-30 g of calcium ammonium nitrate, 20-30 g superfosfatu i 20-30 g of potassium salt of 40 percent per 1 m2. Growing crisp lettuce is similar to growing butter lettuce, however, its growing season is longer and equals 90-150 days. To ensure a continuous harvest of crispy lettuce throughout the summer – since autumn, it must be sown every two weeks, starting in March (with a break from the second half of April to the beginning of May). The break is dictated by the need to avoid harvesting lettuce during the greatest heat waves, which contribute to the bitter of its leaves.
Brittle lettuce is grown from sowing and seedling. In order to obtain the earliest possible harvest, it is sown in boxes on 6-8 weeks before planting the seedlings into the ground. We place boxes on the window in the apartment or in the inspection (the temperature should be
15-20°C, and after sunrises show 15 ° C during the day and 12-13 ° C at night). Crunchy lettuce is planted at greater distances than butter lettuce, namely with a spacing of 45-50X35 cm. The seedlings should not be planted deeper, than it grew before. The seeds are sown in early spring in distant rows 35-45 cm, in depth 0,5 cm. After emergence, when the plants produce 3-4 leaves, there is an intermission, leaving the seedlings at intervals of 20-30 cm. Cultivation of crispy lettuce consists in weeding and loosening the soil to the depth 2-3 cm. Plants should be watered during drought.
There are three varieties of crispy lettuce. For early and late cultivation -Climax. Creates large heads, slightly elongated, medium strict. Vesicular leaves, serrated, dark green, thick, firm, brittle, very tasty. The late variety is the Golden State. Creates large heads, spherical or slightly flattened. The leaves are folded, delicate, vesicular, light green, thick, juicy, brittle. Vanguard is also a late variety. Creates large heads, oval, slightly flattened at the top, medium strict, well closed. Smooth leaves, glossy gray-green exterior, internal yellowish, firm, brittle, very tasty.