Lettuces

Question 1

What are the four types of lettuce and what defines them?

Answer 1

Butterhead: loose head, good rosette of leaves, buttery/sweet taste

Crisphead: round head, dense heart, lots of water

Cos: Upright, thick-leaved

Loose leaf: A loose rosette of leaves rather than a head. Leaves generally curly. Cut-and-come-again types.

Question 2

Name two loose leaf lettuce cultivars.

Answer 2

• ‘Salad Bowl’
• ‘Marvel of Four Seasons’.

Question 3

Name two butterhead lettuce cultivars.

Answer 3

• ‘Arctic King’
• ‘Sabine’.

Question 4

Name two crisphead lettuce cultivars.

Answer 4

• ‘Iceberg’
• ‘Beatrice’

Question 5

Name two cos lettuce cultivars.

Answer 5

• ‘Jewel’
• ‘Winter Density’.

Question 6

Explain soil preparation for lettuces.

Answer 6

• Single dig in autumn and add plenty of organic matter to increase water-holding capacity
• Two weeks prior to sowing apply Growmore 100g/m2.

Question 7

Explain sowing of lettuce.

Answer 7

• Start off in modules or sow in-situ
• Sow under cloches in mid Feb to late March
• Sow main crop outside in April to July
• Sow in August to Oct in a glasshouse or frame
• For early season crop warm soil with cloches for several weeks, then fork over and firm soil, sow, replace cloches
• Sow thinky, 13cm v-shaped drills, 30cm apart
• Seeds should germinate in over a week
• Thin to 7cm, then 25cm.

Question 8

Explain the cultivation of lettuces.

Answer 8

• Must have a regular supply of water (20L/m2 over a week)
• Mulch to conserve water
• Control weeds
• If growth is slow, use liquid nitrogen fertiliser.

Question 9

Explain harvesting of lettuce.

Answer 9

• Ready in 10-12 weeks
• Harvest as soon as heart is firm
• Looseleaf continuously harvested as soon as leaves large enough
• Butterheads need fast harvesting, crispheads may last week longer, cos will “stand” as long as temperature remain cool.

Question 10

Name a pest and a disease of lettuces, including symptoms and control methods.

Answer 10

Slugs and Snails

• irregular holes chewed in leaves
• Encourage predators; beer traps; good garden hygiene; slug pellets

Lettuce Downy Mildew

• Fungal disease with white bloom found on underside of leaves, yellow areas on upperside; disfigured and stunted
• Crop rotation; resistant cultivars; avoid overhead watering.