Lettuce

Lactuca sativa

Lettuce (Lactuca sativa) is a classic cool-season leafy green and one of the most rewarding hydroponic crops. It grows fast, likes cool temperatures and steady feeding.

Mis à jour:

Important notes

heat / long days: In heat lettuce bolts: it sends up a stalk, the leaves turn bitter and ooze white latex. Keep it cool and harvest young.

Lumière

Bright, 12–14 h; dislikes harsh heat.

Arrosage

Evenly moist; drought stress turns leaves bitter and triggers bolting.

Température

Cool: 14–22 °C. Above 24 °C it bolts and turns bitter.

Humidité

50–65 %. Too humid favours leaf rots.

Valeurs cibles par méthode et phase

Hydro
Phase pH EC (mS/cm) Eau °C Air °C Humidité % Lumière h Durée (jours)
Germination 5.8–6.2 0.4–0.8 16–20 15–20 60–70 14 5
Plantule 5.8–6.2 0.8–1.2 16–20 14–20 55–65 14 14
Végétatif 5.6–6.2 1.2–1.8 16–20 14–22 50–65 14 30
Récolte 5.6–6.2 1.2–1.6 16–20 14–20 50–60 13 35
Terre
Phase pH EC (mS/cm) Eau °C Air °C Humidité % Lumière h Durée (jours)
Germination 6.1–6.5 0.4–0.8 15–20 60–70 14 5
Plantule 6.1–6.5 0.8–1.2 14–20 55–65 14 14
Végétatif 5.9–6.5 1.2–1.8 14–22 50–65 14 30
Récolte 5.9–6.5 1.2–1.6 14–20 50–60 13 35
Coco
Phase pH EC (mS/cm) Eau °C Air °C Humidité % Lumière h Durée (jours)
Germination 5.8–6.2 0.4–0.8 16–20 15–20 60–70 14 5
Plantule 5.8–6.2 0.8–1.2 16–20 14–20 55–65 14 14
Végétatif 5.6–6.2 1.2–1.8 16–20 14–22 50–65 14 30
Récolte 5.6–6.2 1.2–1.6 16–20 14–20 50–60 13 35

Problèmes fréquents

Bolting in heat, tipburn from calcium deficiency/fluctuating moisture, aphids, downy mildew.

Pests & diseases

Pest / Disease Symptom Organic treatment
Aphids colonies under leaves rinse off, beneficials
Slugs holes in young leaves hand-pick, slug collars
Downy mildew yellow patches, grey mould beneath spacing, airflow, avoid overhead watering

Edible parts

  • Leaves · edible from Végétatif

Techniques de rendement

Harvest whole or "cut-and-come-again" — take outer leaves and let the heart keep growing.

Propagation & pollination

Method
seed
Germination time
7 days
Germination temp
15-20 °C
Sowing depth
0.3 cm
Pollination
self
Hand pollination needed
no

light germinator — barely cover

Companion planting

🟢 Good neighbours: Coriander (Cilantro), Dill, Garden strawberry

Flavor

mild, fresh, crisp

Storage

In the fridge, wrapped slightly damp.

History

Lettuce was grown in ancient Egypt and was sacred to the fertility god Min. Today it is the world's most important salad plant.

Nutrition

Folate, vitamin K and lots of water — low in calories.

Sources

Florabase

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