Tips for Growing Lettuce
Germination Temperature (Optimum): 6 to 27 °C Max.: 29 °C Min.: 2 °C
Days to Germinate: 7 to 14
Sowing Depth: ½ in.
Indicative Avg. Plant Height: 1 ft.
Spacing In Row: 12 in.
Spacing Between Rows: 18 in.
Avg. Days to Maturity: 40 to 80
Notes: The varied colours and forms of lettuces make them beautiful in the garden. There are 4 different types of lettuce: head, loosehead, leaf and romaine. Most head varieties such as iceberg or great lakes are tough and especially crisp which make them commercial market varieties because they can withstand shipping. Loosehead and leaf varieties are more popular for kitchen gardeners because of their better flavour. Since the root system of lettuce is very shallow it is a good idea to side dress plants with fertilisers occasionally. Moisture is the most important requirement for all greens, so water often. The leaves of the loose head and leaf varieties can be picked as soon as they are big enough to be used in a salad. If you snap off a few outside leaves as needed, the plants last longer and harvesting will be prolonged. Grow best in cool weather with ample moisture, many kinds suffer bottom rot in heat; select summer varieties carefully. In addition, some problems for lettuce and other leafy greens due to heat are: Tip-burn, browning of the edges of the leaves; bitter taste – store harvested leaves in fridge for several days the bitterness will become less; bolting. Most varieties won’t germinate in soil temperatures above 27 °C. Use shade cloth to keep summer lettuce tender and sweet longer. Best time to harvest lettuce is shortly after dawn as the lettuce leaves contain almost double the sugars at 7 am as at 2 pm. Sow every 2 weeks for continuous supply. Lettuce will not head unless thinned frequently and ruthlessly to final distance of 1 ft. Need high dose of nitrogen. Emergence takes 3-5 days at 20 °C, 99% normal seedlings at 25 °C but only 12% normal at 30 °C.
Information provided for guidance only and may vary from one cultivar to another.