There is no other plant (in my opinion) that brings gardeners and non-gardeners together like… No not that plant! I’m speaking of tomatoes. I still get excited when my tomatoes produce and at the end of the season when bombarded with fruit, I still tell myself I will NOT plant as many next year. But it never fails that I get lured into the names, descriptions, and pictures of the interesting, new, or rare heirloom varieties. Hopefully your tomatoes are growing like weeds and maybe you have even harvested some already. But before possible problems arise I’m going to address some common issues and what to do about them. I’m going to be serious about it because, hey!, growing tomatoes is serious. If our crops fail what are we going to snack on, make salsa with, slice into our salads, can ( if you are that domesticated) for sauce??
Blossom End Rot:
This is pretty easy to distinguish because it shows up as a pale white area turning into black mush on the end of the tomato ( the side furthest away from attachment). This is caused by lack of calcium. DO NOT fall for the sprays being sold to solve this problem. They do not work. Calcium is in the soil but for some reason it is not readily available to be utilized by the plant. The main cause is usually fluctuations in soil moisture during fruit set. Make sure plants are not wilting into the night due to dry soil. Tomatoes are set at night and if stressed all sorts of problems can arise. Make sure too that they do not go from bone dry to saturated wet soils. Another problem could be too high of pH. Like iron, calcium can be unavailable to the plant if pH is high. Soil pH tends to be high in the Central Valley and I have never had a problem with blossom end rot so this is more on the rare side. If everything else isn’t working try adding soil sulfur to the soil. This won’t help this years crop too much but the following year there should be an improvement. Some people swear by adding Epsom Salts ( magnesium sulfate) when symptoms show up. Make sure you use this in small qualities – it is a fertilizer. You can also try a diluted spray on the plant but do some research on that.
Splitting of Fruit:
Splitting occurs when, once again, water levels fluctuate too much. Definitely make sure during heavy fruit set that plants are not wilting into the night. The fruit can taste fine with splitting but it’s unsightly and can be a nice home for earwigs and other nasty pests. “Zippering” is different. This looks more like a scar or an actual zipper. This occurs during fruit set when parts of the plant get stuck together. Some varieties are more susceptible and this is nothing to worry about unless you are entering your tomatoes into a beauty contest.
Seems easy enough right – not enough water. Not necessarily. Instead of reaching for the hose, dig into the soil. Watering when a plant doesn’t need it can lead to other problems. Tomatoes will close their leaves at night if temperatures are high. Don’t panic, in the morning the leaves will open. This is a way for them to conserve water. Overwatering will also cause wilting. When a plant has been “drowned” the vascular system of the plant is clogged and is basically suffering drought conditions despite being in wet soils. Once a plant has reached this stage it is tough to reverse. Allow it to dry out and see what happens.
Black Spots on Leaves:
Exactly like it sounds this is black spot. This is a fungal disease that usually shows up early in the season. Like other fungi it is spread by spores so avoid overhead watering and pick off heavily infested leaves. Sulfur spray or dust works but be careful using sulfur when temperatures get above 85, it could burn. Some leaf spot is fine and a plant can usually outgrow the disease.
Verticillium Wilt or Fusarium Wilt:
The “F” and the “V” on tomato labels will tell you if a tomato is resistant to these devastating diseases. These fungi are soil borne and once they get into the plant nothing much can be done. Large sections of the plant will brown, wilt, and eventually the whole plant will die. A brown pith in the center of a stem may be another sign. Remove sections that have died to try to control the spread. If this has been a problem, rotate your tomatos to another location next season, remove and replace a good portion of the soil, and buy resistant varieties. Remember though, lower leaves and even stems will naturally die as the plant grows. This is normal. It is even normal to have a pretty unhealthy looking plant if there is heavy fruit set. Do not worry if some death of leaves occurs here and there.
Lack of Fruit:
There are many possible reasons for lack of fruit. Lack of pollination being one. If pollinators are not around shake the tomato plant (nicely :-)). Tomatoes self-pollinate and this will move the pollen to the right place. Think electric toothbrush equals a buzzing bee. If you have lush beautiful dark green plants and no fruit-STOP fertilizing with Nitrogen. All the energy is going into foliage growth while the goal is to get fruit! Heirlooms are great but sometimes they suck (sorry) at the amount of fruit they produce. We are spoiled with hybrids that are bred for the amount they put out. If you are growing an heirloom, especially known for the individual size of the fruit, don’t be surprised if you get less fruit. Soooo much energy is going into one of those enormous fruits there is not much more the poor plant can do. If fruit is forming and then it drops off, this is usually caused by stress. The plant goes into survival mode and is going to lose anything that is taking its resources . Most likely water stress is to blame. Once again it could be too much or too little during fruit production. Night-time temperatures can be to blame as well. Remember to plant tomatoes when the temperatures are consistently above 50 degrees at night. Sometimes they won’t “snap” back from the stress and be bad producers all season. Also, fluctuations in temperatures can cause flowers and fruit drop. Going from 85 to 105 is stressful to a plant (not to mention people).
Not enough sun! Tomatoes need at least 6 hours of full sun during the day. Morning or afternoon does not matter but the more in the morning the better. They can still produce fruit but most likely shaded plants will produce less and the plant itself may not be able to stay upright as much and break.
There are many other problems that can occur on your tomato plants but generally tomatoes can be the most carefree and rewarding plant any gardener grows. The following are some great websites to check out: