Lettuce
Lactuca sativa
Quick-growing salad green available in many leaf shapes and colors. Tolerates light frost and prefers cooler weather.
Overview
Companion Planting
Carrot
Radish
Strawberry
Chives
Cucumber
Swiss Chard
Arugula
Kohlrabi
Beetroot
Onion
Cilantro
Dill
Sorrel
Cress
Pansy
Celery
ParsleyToxicity
Lettuce is non-toxic and safe for humans, dogs, and cats; dogs should only eat it in moderation and chopped to prevent choking.
Planting Tips
1 cm of water per m² equals 10 liters. Use the Watering Calculator for exact amounts.
Care Tip: Space leaf varieties 20-25 cm apart and head types 30 cm apart; harvest in the morning for crispest leaves and pick outer leaves regularly to extend the harvest.
Common Pests
Aphids
Symptoms: Curled or yellowing leaves, sticky honeydew residue on foliage, and stunted head growth; aphids also transmit mosaic viruses.
Treatment: Dislodge with a strong water spray; for heavy infestations apply insecticidal soap or introduce ladybugs and lacewings.
Prevention: Use floating row covers, encourage beneficial insects, and inspect leaf undersides regularly.
Slugs and Snails
Symptoms: Irregular holes chewed through leaves and a shiny, iridescent slime trail on and around plants; damage is worst overnight.
Treatment: Hand-pick at dusk or dawn; apply iron-phosphate-based slug pellets or scatter diatomaceous earth around plants.
Prevention: Remove garden debris, water in the morning so soil dries by evening, and use copper tape barriers around beds.
Cutworms
Symptoms: Seedlings cut cleanly at the soil line and found wilted or toppled in the morning; larvae curl into a C-shape when disturbed.
Treatment: Apply Bacillus thuringiensis (Bt) or beneficial nematodes to the soil; hand-pick larvae at night with a flashlight.
Prevention: Place cardboard or foil collars around transplant stems at planting time and keep the area free of weeds.
Common Diseases
Downy Mildew (Bremia lactucae)
Symptoms: Light green to yellow angular spots on upper leaf surfaces with white-gray fuzzy growth underneath; older outer leaves are attacked first.
Treatment: Remove and destroy infected leaves promptly; apply copper-based fungicides at the first sign of infection.
Prevention: Ensure good air circulation with adequate spacing, avoid overhead watering, and choose resistant cultivars when available.
Lettuce Drop (Sclerotinia spp.)
Symptoms: Sudden wilting and collapse of the whole plant; white cottony fungal growth and hard black sclerotia appear at the stem base.
Treatment: Remove and bag infected plants immediately; apply fungicides containing boscalid or fluazinam to surrounding soil.
Prevention: Rotate crops on a 3-year cycle, use drip irrigation to keep foliage dry, and solarize soil in summer to kill sclerotia.
Gray Mold (Botrytis cinerea)
Symptoms: Water-soaked brown lesions on lower leaves that develop a fuzzy gray spore mass; soft rot spreads to stems in cool, humid conditions.
Treatment: Prune and dispose of all infected tissue in sealed bags; improve ventilation and reduce humidity around plants.
Prevention: Space plants for good airflow, water at the base in the morning, and promptly remove dead or aging outer leaves.