Leaf Rot

Leaf rot causes crisp, leafy greens to turn brown and mushy. Your spinach, endive, escarole, lettuces, mustards, and Swiss chard are all susceptible. So are your lentils, strawberries, beans, peas, okra, and many cucurbits.

Rotting lettuce (Rasbak) CC BY-SA 3.0

What is leaf rot?

You’ve seen it in your refrigerator. You place a fresh head of lettuce in the crisper drawer. The next time you look, the leaves have turned brown and mushy. What happened?

Wherever fungi or bacteria find a hospitable location, they start feeding and reproducing, and rot begins. Rotting is the breakdown of complex structures by those tiny life forms.

Causes of leaf rot

Leaf rot can occur when leaves stay wet too long. Leaf rot can also be a symptom of many diseases commonly caused by Fusarium, Pythium, Phytophthora, and Rhizoctonia. These leaf rot diseases include cherry mottle, cucurbit wet rot, carrot leaf rot, lentil leaf rot, pigeon pea leaf rot, and white mold.

Like most rots, moisture is a critical component. Allowing water to sit on your leafy greens is all it takes. Soggy soil contributes to the problem.

Preventing leaf rot

Rather than losing your leafy greens and other garden favorites to leaf rot, take these steps to prevent the problem:

• Select plants best suited to your microclimate.
• Avoid overwatering. 
• Provide good drainage.
• Use drip irrigation, a soaker hose, or furrow irrigation instead of overhead watering.
• Space plants for better airflow.

If leaf rot does occur, dig up infected plants and throw them in the trash. Their neighboring plants will thank you.