Question
What causes the leaves on the tomato plant to curl

Answer
Excessive fertilizing, especially with a high nitrogen fertilizer such as standard Miracle-Gro, can cause the type of symptoms you have described.

The high nitrogen levels can adversely affect the foliage on young plants and the high salt content in most synthetic fertilizers can result in root burn. My advice, especially while the plants are still young, is to fertilize once every 14 days at half strength to prevent excess salt buildup in the soil.

Another option is to purchase a water soluble fertilizer recommended specifically for tomatoes. Miracle-Gro makes such a product, as does Peter抯 and Schultz. These tend to be higher in phosphorus and potassium which are essential for good production and larger fruits.

Overwatering can definitely cause leaf curl on tomatoes. This is especially prevalent when using containers with poor drainage. The result is poor root development, and nutrients being leached from the soil. Make sure you supplement the plants with 1.5?of water per week by watering very deeply once or twice per week. More may be required during periods of drought. Shallow watering causes the roots to reach for the surface instead of deep into the soil. The result is weakened plants with little
or no harvest.

One other possibility is that plant has become root bound. Tomatoes should be transplanted twice to larger pots prior to planting in the garden or into containers. They are one of the few plants that actually thrive when transplanted. They also should be planted several inches deeper each time. This allows the bottom of their stems to produce root nodules that result in a stockier and stronger plant. It will also aid in increasing the harvest once the plant begins producing.

Finally, make sure the plants are well mulched with either straw, shredded leaves, or aged grass clippings. This will help retain moisture while keeping the roots cool. Next year, work in as much organic matter as possible to the soil. This would include humus, compost, and manure. This will prevent disease and improve the overall tilth of your soil.

I hope this answered your question. Please write again if I can ever be of assistance.

Regards,

Mike