Leaf Lettuce Leaves Turning Yellow: Causes & How to Fix It

Check these first

• Does the yellowing start at the bottom of the plant or at the tips?
• Are the veins still green while the rest of the leaf fades? That points to a nutrient deficiency.
• Look under the leaves for tiny insects or white specks.

Most likely causes

From the pests and diseases recorded for this plant, the ones whose symptoms match, most serious first. Symptoms alone rarely confirm a cause, so use the linked page to check the signs and treatment.

Other possible causes

• Powdery Mildew — White patches appear scattered on the upper leaf surface at first, then the whole leaf is …
• Downy Mildew — Pale yellow to yellow-brown angular lesions form on the upper leaf surface with a gray-pur…
• Rust — Small raised orange-yellow to red-brown pustules form on both leaf surfaces, then rupture …
• Leaf Spot — Small round brown to gray-white lesions appear on the lower leaves, the centers turning gr…
• Root Rot — Fine roots rot brown to blackish brown, growth stops and the lower leaves yellow. The plan…
• Fusarium Yellows — Yellowing starts on the lower leaves, the petioles twist and the plant leans to one side. …
• Root-lesion Nematode — Elongated blackish brown necrotic lesions form on the root surface and fine roots rot away…

Other symptoms on this plant

What other growers did about it

A page like this one can tell you what leaf lettuce leaves turning yellow is and what to try. What it cannot tell you is what actually happened to someone who had it on the same plant, at the same point in the season, and what they did next.

Gadenin is a free garden journal built around that. You photograph the plant, tag what you are seeing, and the entries line up by date for each plant you grow.

• Tag the problem and the app tells you how many other growers have logged the same thing on the same plant.
• Growers who make their records public can be followed, so you can read what they did and how it turned out.
• Next season your own entries come back at the same point in the year, so you check the plant before it starts.

Written byYasuGrowing vegetables and fruit in Chiba, Japan, and building Gadenin. Corrections are welcome. 15 years of growing.