Spindly stems

by Margaret Luscombe
(UK)

Q. I have been growing tomatoes in the greenhouse for over 20 years and have never had the problem I have had this year. This year my plants are very spindly with only a few leaves and little blossom. The two varieties are Money Maker and cherry. I thought the problem was due to the cold spring and summer but have noticed some outdoor tomatoes which have grown by accident are much healthier. Have you any suggestions what the problem is?

A. Several problems can cause tomato plants to be spindly or exhibit stunted growth.

• Insufficient light. Have you had consistently cloudy days? That could prevent normal light for your plants. Tomatoes need 6-8 hours of light per day.
  
• Inconsistent temperatures. Check the greenhouse for drafts.
  
• Cold temperatures. What do you do in the greenhouse when it is especially cool outside or when you have a cold snap?
  
• Nutrient deficiencies. Have you provided plants with balanced fertilizer at regular intervals?
  
• Whiteflies. Though often undetectable to the eye, these pests suck juices from leaves, causing wilting, leaf damage, brown leaves, and stunted growth.
  
• Wilts. Verticillium wilt, fusarium wilt, bacterial wilt, and even walnut wilt -- all these diseases all can contribute to stunted tomato plants.
  
• Root damage. If roots aren't operating correctly, then plants cannot get water and nutrients and won't grow. By the same token, overwatering will "drown" plants, stunting their growth.