What is wrong with my lettuce? Salad green growing questions answered


Jenny answers six common questions about what could be going wrong when it comes to growing lettuce.

Words and Images: Jenny Somervell

WHAT IS EATING MY SEEDLINGS?

Slugs and snails love lettuces – if there is a slime trail, assume it is a slug or snail. Check your slug pellets are not toxic to birds and pets that may eat the dying slugs.

WHY ARE MY SEEDLINGS DYING?

Sudden death or wilting may be due to soil-borne fungus diseases. For container growing, use a proprietary potting mix, and clean trays before sowing with soap and hot water. Sow thinly, keep well ventilated and avoid watering in the evening or in cold weather. Water with dilute seaweed to increase plant resistance.

WHY ARE MY PLANTS ROTTING AT THE CROWN?

This may be caused by fungal diseases exacerbated by overcrowding, a lack of ventilation, or planting the stem too low in the soil. If possible, water at soil level to avoid wetting the leaves. Remove all infected material.

WHAT DOES A WHITE, COTTONY MOULD UNDER THE LOWER LEAVES INDICATE?

This is sclerotinia, a soil-borne fungal disease. Remove all infected material and, if possible, avoid planting lettuces in the same spot for several seasons.

WHAT CAUSES CURLED, DISTORTED LEAVES AND STUNTING?

Look for aphids which also carry virus diseases. Eliminate with insecticidal soap.

Aphid.

WHY ARE MY LETTUCES BITTER?

Bitterness is usually due to slow growth caused by too much heat or cold, or a lack of moisture and nutrients. Lettuces need to be kept actively growing for sweet tasting leaves.

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NZ Lifestyle Block This article first appeared in NZ Lifestyle Block Magazine.
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