Lactuca sativa

Lettuce Growing & Harvesting Guide

Lettuce (Lactuca sativa) is the crisp, refreshing heart of the home salad garden. Famed for its highly tender, jade-green leaves and rapid growth, this cool-season annual thrives under consistent moisture and brings instant fresh crunch to the kitchen table.

Sunlight Full Sun / Partial Shade

Watering Consistent / Deep

Soil pH Rich, Moisture-Retentive (pH 6.0-6.8)

Target Temp 12°C - 20°C

Toxicity Pet Friendly (Non-toxic)

Botanical macro photography of Lettuce (Lactuca sativa) - Plant AI care database

How to Identify Lettuce

Lettuce (Lactuca sativa) is a highly valued edible crop globally. Recognizing its definitive vegetative and fruit/vegetable structures is key to successful companion growing and harvesting.

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Key Visual Features: Low-growing, compact annuals forming loose rosette leaf clusters or dense round heads.
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Leaf & Stems: Succulent, smooth or ruffled green-red leaves with delicate, watery veins.
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Fruit/Edible Part: Tender, mild-flavored leaves harvested individually or as a whole compact crisp head.

💡 Plant AI Tip: Snap a photo with Plant AI to identify garden veggies and diagnose leaf spot diseases in 1 second.

Complete Growing & Harvesting Guide

Follow our detailed scientific agricultural cultivation guide to keep your Lettuce thriving and high-yielding.

Water regularly once a week, receiving 1 to 1.5 inches of water. Shallow roots require consistently moist soil.

Prune away only yellowing lower outer foliage. Harvest lower leaves continuously using a 'cut-and-come-again' method.

Apply balanced organic fertilizer high in nitrogen once every 3-4 weeks to support rapid tender leaf growth.

Thrives in full sun but benefits from afternoon shade in warm climates. Afternoon shade prevents bitter leaves.

Prefers fertile, fast-draining sandy loam rich in organic compost (pH 6.0-6.8) with high moisture-retention capacity.

Sow seeds directly outdoors in early spring or late summer once soil is workable. Plant seeds very shallow.

Thrives in cool climates. Ideal temperature range is 12°C-20°C. High heat (above 24°C) triggers early bolting.

Space plants 6-12 inches apart. Crowded plants fail to expand and are highly prone to pest infestations.

Prone to aphids, slugs, and snails. Apply organic neem oil spray and use diatomaceous earth proactively.

Susceptible to Powdery Mildew and Bottom Rot. Ensure excellent soil drainage and avoid overhead watering.

Harvest entire heads at 45-50 days by cutting at the soil line, or harvest outer leaves continuously as needed.

Common Diseases & Treatment

Lettuce Bolting (Physiological)

Symptoms: The plant rapidly sends up a central flower stalk with yellow blooms, causing leaves to turn tough, milky, and bitter.

Action: Plant during cool seasons, protect from sudden heat, and harvest immediately at first sign of stalk.

Bottom Rot (Rhizoctonia)

Symptoms: Water-soaked lesions appear on lower leaf stems touching damp soil, turning soft, brown, and rotting rapidly.

Action: Improve soil drainage, reduce watering, remove infected leaves immediately, and avoid overhead watering.

Frequently Asked Questions

Why are my lettuce leaves turning bitter?

High temperatures (above 24°C), water stress, or early bolting cause the plant to produce bitter milky latex. Provide afternoon shade.

How many days does it take to grow lettuce from seed?

Leaf lettuce grows extremely fast, maturing in 40-45 days, while head lettuces take 60-70 days from seed.

Can I grow lettuce indoors under lights?

Yes! Lettuce is perfect for indoor hydroponics or small pots under LED grow lights. Keep temperature cool (18°C-21°C).

Is romaine lettuce safe for pet cats?

Yes. Lettuce is completely non-toxic and pet-safe in small quantities. It provides healthy hydration and dietary fiber for cats.