Tip Burn

Disorderalso: Tipburn, Leaf tip burn

A physiological disorder, not a disease, in which the leaf tips and margins of lettuce, cabbage, and other leafy crops turn brown and die. It comes from a calcium shortage in the fast-growing inner leaves, usually driven by uneven water and rapid growth rather than by low soil calcium, and it often hides in the center of a head until you cut it open.

🔎 How to spot it

Look for browning, drying, and curling of the tips and edges of young, rapidly growing leaves. In heading crops like lettuce and cabbage the worst damage is on the hidden inner leaves, so the outside can look fine while the heart is brown and slimy, sometimes inviting secondary soft rots. It is most common in warm spells during quick growth.

🥀 Damage it causes

The browned leaf tips and margins downgrade or ruin the crop, and on heading lettuce and cabbage the internal browning can spoil the head and open it to rot. It does not spread plant to plant, but a heat-and-growth spurt can hit many plants at once across a bed.

🔬 What causes it

Tip burn is a localized calcium deficiency in the rapidly expanding leaf tips, where calcium demand outruns supply. Because calcium moves with water, it is driven by anything that disrupts steady uptake, water stress, hot weather, fast lush growth, and heavy fertilizer that competes with calcium, rather than by genuinely low soil calcium.

🛡️ Prevent it

Keep growth steady and water even, avoiding swings between dry and wet, and irrigate more often in heat to prevent stress. Go easy on nitrogen and avoid over-fertilizing, which pushes the fast growth that triggers it. Choose tip-burn-tolerant varieties, provide some afternoon shade in hot spells, and harvest promptly before heads overmature.

🧯 If it is already here

There is no cure for already-browned tissue, so trim off affected outer leaves and use what is sound, and harvest heads before the damage spreads inside. Then steady the watering and ease off nitrogen for the rest of the crop. As with blossom-end rot, consistent moisture and unforced growth are the real fix, not a calcium spray.

💡 Good to know

Tip burn is the leafy-crop cousin of blossom-end rot: both are calcium-delivery problems caused by uneven water and fast growth, not by low soil calcium. Because the worst of it can hide inside a lettuce or cabbage head, a plant can look healthy until harvest. Steady moisture and moderate feeding prevent most cases.

For educational and informational purposes only. Disease management advice is general guidance drawn from university cooperative extension sources; always identify a problem positively and read and follow the label on any product before use, especially around food crops, children, and pets.