Tomatoes

My grandfathers made it looks so easy. Vine ripe home grown tomatoes bursting with flavor and juiciness were so plentiful as a kid that I just took them for granted.

Truth be told I’ve grown tomatoes before without much hassle but since moving to coastal NC it’s been pretty hit and miss. This year I decided to do the necessary reading and research to determine what was so frequently going wrong. In the end I believe I’ve learned what I need too in order to have a reliable yield next year.

Perhaps my most important victory this year was to correctly identify the diseases that have been plaguing my tomatoes for several years. The first and worst of these is early blight. This is a nasty little soil fungus that tends to accumulate in gardens that routinely grow tomatoes. There is no such thing as blight resistant plant, which was my first mistake. When you see varieties listed as resistant this is generally referring to the various forms of wilt but more on that latter.

The prime natural controls for early blight are crop rotation and removal of diseased material from the garden. A good rotation of crops deprived the blight organism of a host and so it becomes attenuated in the soil. I’m not sure you can ever be rid of this disease but if it only exists as a part of a balanced soil flora it’s less likely to cause significant damage to crops.

Prompt removal of diseased plants is critical in preventing further spread of the organism to neighboring plants. Equally important is removing tomato vines from the garden at the end of the season so they don’t serve to help the fungus overwinter. While it is easy to understand that you wouldn’t throw diseased plants into the compost pile, I’ve made it a practice not to put ANY tomato produces into the pile. As compose is spread throughout the garden doing so would defeat the positive effects of rotating my crops.

Plant spacing and moisture control are also important in controlling blight. Blight loves cool damp conditions so evening watering is not a good idea. Instead it’s advisable to water in the morning or early afternoon so that the foliage has time to dry before nightfall and the onset of cooler temperatures. Wider spacing of plants also facilitates adequate air flow around the plant to help the drying process. Keeping the plants staked and off the ground is another important method of control. Remember that blight is a soil dwelling fungus and whenever foliage has the opportunity to contact soil the chance of infection is increased. To this end some recommend trimming plant’s lower branches to keep them off the ground and a good layer of mulch to prevent soil particles from splashing onto foliage when it rains.

This year I have very little issue with blight. Even though tomatoes had been grown in the same spot for the last two years, adequate, spacing, staking, pruning, mulching and timely irrigation seemed to control the disease quite well and no chemicals were needed.

The second disease I have in the garden affecting tomatoes is bacterial wilt. Wilts affect the plant’s roots and their ability to take up adequate moisture. Most of the time the vines will look healthy but during the heat of the day they wilt back because they can’t take in enough moisture. Generally the plants rebound as the day lengthens but such repeated stress on the plants makes them susceptible to other diseases and interferes with proper setting and formation of fruit.

Natural controls for wilt are rotation, spacing, soil preparation and selecting the proper variety. Rotation controls the wilt organism the same way as with blight while spacing and soil preparation allow for maximum root growth and moisture uptake. Variety selection is important in that some show resistance to the disease.

As this season approached I did some research and selected three varieties that were know for good resistance to bacterial wilt. The resistant varieties were selected for varying fruit characteristics and because they had indeterminate vines. Indeteminant plants grow and fruit throughout the season. With these three varieties I had hoped to produce a sustainable crop of varied fruits right up to the first frost. As it turns out, all three "varieties" were determinant plants which generally grow to a certain size, set fruit over a much shorter season and are done for the year. They are great when growing for the mass market or when you plan to preserve your crop but for fresh eating its feast then famine and our feast was largely over by the end of July!

The big lesson here however is not the difference between the two types of vines. The important aspect is but that you have to be careful who you buy your plants and or seed from! The three distinct varieties I planted all look and performed exactly the same. Vine characteristic being completely off alone is sufficient to support the conclusion that they were not the varieties I believed them to be. That the fruit the plants set was decidedly inferior is enough to tell that they were likely some form of uncontrolled hybrid. As always, I bought my plants this year from a respected garden center but it’s quite obvious that either the seed supplier had insufficient controls to propagate varietals or the garden center failed to track and label their inventory properly. To get around these unknown I’ve decided that next year we will be starting our tomatoes from seed purchased from the venerable Southern Seed Exchange. One can not take the initial input into a garden for granted if you want reliable and predicable results year after year.