Between toasted tomato sandwich time and now, you’re going to want to ask some tomato care questions, so here’s the fast and furious problem-detector system.
Black Spots on Bottom
If your tomatoes are ripening up just fine and you’ve harvested the early ones only to find a brown, sunken spot on the bottom of the fruit – you’ve got blossom end rot.
This problem is not a disease but rather a tomato care or physiological problem.
You didn’t get enough calcium to the fruit when it needed it.
Causes of Blossom End Rot
- Water Shortage: I know a lot of gardeners run around trying to get calcium into the soil when they hear this but the fact it – in 99.9 percent of all cases, it is a water shortage problem (you need water to move calcium) rather than a calcium problem.
- Cool Nights: Another cause of this problem is cool nights too early on when the first fruit set was setting pollen and being pollinated. Out of control of the gardener without frost protection netting.
- Too Hot Days: later in the season, temperatures that are too high can also have an effect on tomatoes. This is more a problem in Southern states than it is in the north.
Even though the first fruit set has the problem, you can stop other truss sets from getting it by turning on the hose to provide a full inch to 2 inches of water a week for each plant.
If you have tomato gardening questions, you’ll want to check out this resource.
Low yields on the first truss (that’s the technical name for the cluster of tomatoes) are often the result of cool nights when the pollen was forming.
Cool nights (below 55 F) will cause the pollen to go sterile. One advantage of some of the cold-resistant varieties like sub-arctic maxi is that the pollen does not go sterile until the thermometer dips much lower than 55.
Unfortunately, the taste of many of these cold-hardy varieties does not match that of the more heat loving plants and no amount of hard work and tomato care techniques will greatly improve this.
In rare cases, magnesium deficiency can be a problem that causes blossom drop, blossom end rot and a lack of a fruit set. Again, this is rare and you’ll know it because the tomato leaves will be mottled. If the leaves are not mottled but are straight green, it’s not a magnesium deficiency but a cultural problem.
Otherwise you have a cultural problem: not enough light, poor soil fertility, poor watering habits.
Big Green Worms
I know I’m going to hear about these guys at some point in the summer. Tomato hornworms are one of the larger larva (about 4 inches long) that chow down on garden plants.
These huge worms are bright green with white stripes down their side and a large black eyespot and black tail (on the back end). The feed during the day and if you are quiet, you can hear them munching away on a still day. You’ll know you’ve got them if you suddenly find no leaves on parts of the plant and the only sign that the leaf was there is a stub of a stalk
You’ll find them in the daytime but you’ll have to look closely because they are well-hidden. It is easier to handpick them (step on them once you find them) than spray because while the damage looks like there’s millions of them, my experience is that there’s usually only one or two in the plant.
Do understand these worms also eat peppers, potatoes, eggplant and dill and their flying stage is gray-brown moth with a 5 inch wingspan. Plant some dill next to your tomatoes if you have a problem with this pest – it prefers dill to tomatoes and is more easily found (and squashed) on the dill plant.
The only other insect that can be a problem for tomatoes at this time of year is the aphid (or more likely aphids) If your plants are struggling, aphids are the firefighters of the insect world and will be the first to try to recycle your garden for Mother Nature.
A sharp jet of water will knock them off the plant or a spray of soapy water will kill them. Just understand that when you see hordes of aphids, you know the plant is not healthy to begin with. I would recommend immediate feeding with fish emulsion (at recommended amounts as per label) and I’d continue this for the rest of the growing season to try to bring the plant back to health so the aphids will not be attracted.
Sometimes, you’ll see flea beetles on your tomatoes. Well, actually you’ll have to be fast to see them
These are tiny black insects that take bites out of the center of your leaves and you’ll hardly ever see them because as you walk into your garden, they are jumping (like fleas) out of sight.
They are very sensitive to predator motion (you) and jump very fast and very far. You might see them if you have a severe infestation and you creep very quietly without moving leaves
Generally, I’ve never found them to be a major pest and I don’t panic when I see some holes in a few leaves. Sure, they’re there but a hole here or there but they aren’t in the same league as the tomato hornworm when it comes to damage.
Sometimes Colorado Potato Beetles decide to chow down on tomatoes and if this is the case, there are two remedies that seem to work.
- The first is handpicking early in the morning. You’ll get most of them this way if you go at it every morning for a week.
- The second is to dust your plants with rotenone.With severe infestations, this will knock the beetle back. But read the label with Rotenone – it is not something to mess about with even though it is “organic”. (dust masks mandatory!)