Growing lettuce is the quickest and easiest way to start with hydroponics. It matures in quickly, tolerates minor mistakes, and thrives in simple systems like NFT and DWC.
To get crisp, healthy leaves, aim for these settings:
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pH Range: 5.5 to 6.0 (Target 5.8)
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EC Range: 0.9 to 1.4 mS/cm (Lettuce prefers weak nutrients)
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Water Temp: 16°C to 20°C (Warm water makes lettuce bolt & turn bitter)
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Lighting: 14 to 16 hours of light per day under standard LED grow lights
Step-by-Step Growing Guide
1. Germination (Days 1–7)
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Place a lettuce seed inside a pre-moistened rockwool cube or coco pod.
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Keep the medium damp with plain, pH-adjusted water (no nutrients yet).
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Place them in a warm spot which has some light. Lettuce seeds need some light to germinate. Once sprouts emerge, move them immediately under grow lights to prevent them from stretching.
2. The Seedling Phase (Days 8–14)
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When you see the first true leaves, start feeding them a weak nutrient solution at an EC of about 0.6.
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Wait until the roots begin poking out of the bottom of the rockwool cube.
3. Transplantation (Day 15)
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Move the seedling into your hydroponic system.
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Deep Water Culture (DWC) buckets or Nutrient Film Technique (NFT) pipes are the usually best choices for lettuce.
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Drop your net pots into the system and ensure the water level just touches the bottom of the root zone. Increase your nutrient strength to an EC of 1.0 to 1.4.
4. Vegging & Harvesting (Days 16–30+)
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Keep your water moving and highly oxygenated with an air pump.
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Harvest Method 1 (Continuous): Pick the outer leaves as they grow. The plant will keep producing new leaves from the centre for weeks.
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Harvest Method 2 (Whole Plant): Remove the entire plant from the system around day 30 to 35.
⚠️ 3 Mistakes to Avoid
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Preventing "Tip Burn": If the edges of your lettuce leaves look dry and brown, it is usually a calcium deficiency caused by high humidity or lack of airflow. Place a small oscillating fan near your plants to keep air moving. Ensure there is enough calcium in the hydroponic nutrient.
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Avoid Bolting: If lettuce gets too hot (above 24°C) or receives too many hours of light, it will grow a tall central flower stalk, stop producing leaves, and turn bitter. Keep your grow room cool.
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Overcrowding: Space your lettuce plants at least 15 to 20 cm apart. If they are packed too tightly, they will block each other's light and trap moisture, inviting powdery mildew.