Head Lettuce (Lactuca sativa var. capitata)

Head Lettuce

Lactuca sativa var. capitata

Crunchy, crisp leaves form tight, edible heads. Cool-season leafy vegetable; common names: iceberg lettuce, head lettuce.

Partial sun
2–3/week
Beginner
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Plant Needs

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Sunlight Partial sun to full sun; tolerate light shade in hot climates to prevent premature bolting
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Watering Keep soil consistently moist but not waterlogged; avoid drought stress to maintain leaf crispness
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Temperature Thrives in cool temperatures; bolts rapidly above 24°C; tolerate light frost
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Characteristics

  • Leaf: Tight, overlapping, crisp pale green to white leaves forming dense, round heads; outer leaves darker green.
  • Stem: Thick, fleshy central stem supporting the head; elongates when bolting to produce flowers.
  • Flower: Small, daisy-like yellow composite flowers on tall, branching stalks when bolting.
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Horticulturist's Insider Field Notes (No AI Fluff)

The Golden 'Finger Test' Rule

Never water on a strict calendar. Stick your index finger 2 inches into the soil. If it feels cool and damp, wait 2–3 days. If bone dry, water thoroughly until it drains from the bottom holes.

Empty the Saucer After 20 Minutes

The #1 houseplant killer is water sitting in the catch tray. Stagnant runoff water starves roots of oxygen and causes root rot.

Turn the Pot Every 2 Weeks

Houseplants naturally lean toward the nearest window light. Give the pot a quarter-turn biweekly to maintain balanced, symmetrical architecture.

Wipe the Dust Away

Dust on leaves acts like a heavy sunshade. Gently wipe broad foliage with a damp cloth monthly to maximize photosynthesis and air purification.

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Care Guide

Watering

Keep soil evenly moist; water deeply 2–3 times weekly to avoid dry soil

Fertilization

Apply diluted balanced liquid feed every 2 weeks. Use nitrogen-rich feed to promote leaf growth in early stages

Composted eggshell tea:Steep crushed, dried eggshells in water for 3 days; dilute 1:10 for root drench to boost calcium levels and reduce leaf tip burn
Pruning
  • Remove outer yellowing leaves to maintain head health and improve airflow
  • Cut back bolting stalks promptly to redirect energy to leaf growth if early bolting occurs
  • Harvest entire head by cutting at the base when fully formed; leave outer leaves for limited regrowth in some varieties
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Pet & Human Toxicity & Emergency Guide

🟢 Pet-Safe (Non-Toxic to Cats & Dogs)

Pet Safety Verified: According to clinical veterinary databases (ASPCA), Head Lettuce (Lactuca sativa var. capitata) is non-toxic to both cats and dogs, making it an excellent choice for pet-friendly homes.

Pet Tolerance

Leaves, stems, and flowers contain no systemic toxins or hazardous oxalates; safe for curious puppies and kittens.

Mild Fiber Sensitivity

While non-toxic, excessive consumption of fibrous leaves may cause mild, temporary stomach upset or regurgitation.

Recommended Placement

Safe for low tables, living rooms, and active pet environments.

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Troubleshooting & Common Plant Problems

Quick diagnostic guide for common care issues affecting Head Lettuce (Lactuca sativa var. capitata):

Yellowing Leaves

Most commonly caused by overwatering or poor drainage. Ensure topsoil dries out between waterings and check for root ventilation.

Brown or Crispy Leaf Tips

Low ambient humidity, hard tap water minerals, or direct midday sunburn. Increase humidity and use filtered water.

Drooping or Wilting Foliage

Indicates dehydration or root damage from prolonged waterlogging. Inspect soil moisture and root firmness.

Common Pests (Spider Mites, Aphids)

Dry indoor air encourages pests. Wipe leaves with a damp cloth and treat with insecticidal soap or neem oil.

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Propagation & Repotting Guide

  • Taking Cuttings: During active spring or summer growth, take a healthy 4–6 inch cutting just below a node using clean shears.
  • Rooting Medium: Place cuttings in fresh water or moist perlite mix in bright, indirect light; refresh water weekly.
  • Potting Up: Transplant into well-draining potting mix once roots reach 2 inches in length (typically 3–5 weeks).
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Seasonal Care Calendar

  • Spring & Summer (Active Growth): Water thoroughly as topsoil dries; apply diluted balanced fertilizer monthly; encourage steady growth.
  • Autumn (Transition): Gradually reduce watering frequency as daylight hours shorten; discontinue fertilization.
  • Winter (Dormancy): Water sparingly only when soil is mostly dry; protect from cold window drafts; keep in warm room.
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Frequently Asked Questions

How often should I water my Head Lettuce?

Water thoroughly when the top 1–2 inches of soil feel dry. In active growth (spring/summer), water every 1–2 weeks; reduce significantly in winter.

Where is the best indoor location for Head Lettuce?

Position in bright, filtered indirect light (e.g., near an east or south-facing window with sheer curtains). Avoid harsh direct midday sun.

Is Head Lettuce toxic to pets?

ASPCA confirmed non-toxic; no adverse effects from ingestion

When should I repot my Head Lettuce?

Repot every 1–2 years in spring when roots outgrow the drainage holes or the soil depletes nutrients.

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Garden Uses & Culture

Culture: N/A

Usage: Edible leafy vegetable for salads, sandwiches, and wraps; ornamental edible garden plant

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