Tipburn

About

Browning of leaf edges in lettuce, cabbage and related crops, often hidden inside the head. It happens when leaves grow faster than calcium can reach them, usually in hot weather near harvest.

Also called tipburn, tip burn

How to recognize it

Symptoms

Small dark brown spots form along the edges of inner or outer head leaves and join into dead brown margins that dry and turn papery. Damage is often inside the head where you cannot see it, and soft rot bacteria may move into the dead tissue.

Worse when

Hot weather (especially nights above 65°F) as heads form, very fast growth from heavy nitrogen, and uneven watering as the crop matures.

How it spreads

It does not spread from plant to plant.

When

Late spring through summer as heads mature.

What to do, gentlest first

This is not an infection, so sprays for diseases won't help. Fix the cause below.

1. Water evenly Prevent

   Keep soil steadily moist as heads form, avoiding both dry spells and waterlogging.

2. Avoid excess nitrogen Prevent

   Fertilize by soil test and do not push growth with extra nitrogen; nitrate forms are preferred over ammonium.

   Adding calcium to the soil or spraying it on leaves has not reliably fixed tipburn in field tests.

3. Choose less-prone varieties Prevent

   Varieties differ; Ithaca and Summertime lettuce are recommended in the Pacific Northwest.

4. Harvest on time By hand

   Pick heads as soon as they are mature; tipburn is worse on overmature lettuce, and prompt harvest reduces it in cabbage family crops.

Plants it affects

Bok choy, Broccoli, Cabbage, Cauliflower, Endive and escarole, Lettuce, Napa cabbage