Giving tomato plants the proper attention at planting time is the most important step you can take to ensuring a satisfying harvest. However, even with the best care initially, keeping your tomatoes growing strong will require some mid-season care as they head toward harvest time.
Once the plants start to flower and form new tomatoes, keep an eye out for leaf spot or leaf curl on the plant. Another sign of trouble is leaf drop or yellowing leaves. Unfortunately, many diseases common to tomatoes look similar. Some are preventable, some are treatable, and yet others are neither, such as a virus. The best preventative measures for disease on tomato plants is to be sure to have a 2-4 inch layer of mulch around the base of each plant. This will help a great deal in preventing soil-borne disease from splashing up onto the foliage from irrigation or rainwater. Water plants with soaker hoses, or at the very least water at the base of the plant. If you must water from above, do it early in the day so the foliage has plenty of time to dry out. Foliage that is wet for too long can promote disease. Don’t over fertilize but keep a good supply of compost around the plant. It is a great source of nutrition, and it contains disease-fighting properties. Once disease is present, it is very difficult to reverse. However, you can in many cases prevent it from happening. Before any sign of disease on your tomato plant, start spraying each plant with a combination of bactericide and fungicide. Combine a copper base solution for the bacteria and a fungicide such as Daconil 2787 into a pump sprayer. Follow the directions on the labels for proper mixing instructions. About every week, apply this solution to the plant foliage and along the stem. According to one well-respected university plant pathologist I know, 90% of the preventable disease problems occurring in home vegetable gardens can be avoided by using this method. However, even with a consistent maintenance program, which includes watering only at soil level, providing good air circulation and spraying routinely with a bactericide/fungicide, environmental conditions may still promote disease. In these cases, remove diseased foliage from the plant at the first sign of problems. This will likely occur on the lowest part of the plant initially.
There are a number of pests that attack tomato plants. One of the most common is the tomato hornworm. This hard to see but intimidating creature can do a lot of damage to a plant in the course of 24 hours. You know you have this pest when you find much of the foliage eaten within a short period. Another sign of the hornworms’ presence is the droppings they produce. They usually appear at the base of the plant and look like small black soccer balls. Control of the hornworm is simple. Once you locate this well camouflaged creature, handpick them off and toss them out of the garden where a bird is sure to find him. Another method to control the population is to use Bt (Bacillus thuringiensis). You can find this in a canister at most nurseries and garden centers. A very favorable aspect to this product is that it is selective; specific only to the hornworm. It is a biological control that won’t harm beneficial insects, pets or people. Apply a dusting of this powder to your plants once you notice a problem and re-apply if rain washes it off.
To promote faster growth and concentrate the plant’s energy into the main branches, snap or cut out the small suckers that grow from the crotch of many branches and the main stalk. As tomato plants grow, they will need support. Make sure to provide staking or support to keep the plant from falling over and possibly breaking. Staking also provides air circulation and penetration of sunlight. A better harvest will more likely be the result. If you find that the plant is growing too tall to manage, you can cut the top off. Be sure to make a clean cut, just above a side branch. The key is to stay ahead of any problems by maintaining a healthy garden as described above and inspecting it often. By employing some mid season care you can keep your tomatoes growing strong and greatly improve the chances of experiencing your best harvest yet.