The tomato plants in our local gardens should be flowering or even fruiting by this week. But it can be a long, treacherous road between flowers and early fruit to a sustained harvest of ripe, juicy tomatoes.
Take water, for example. Rain supplies a balanced and micronutrient-rich water source to our plants. But the heavy amounts falling this year (close to 2” above average for January through April), together with the high humidity and rising temperatures, have created near-perfect conditions for a whopping outbreak of early blight (Alternaria solani) on our tomato and potato plants. What follows is a mini list of tomato terrors that you can outfox, if you’re prepared — and lucky.
The first sign of this common fungal disease is the appearance of brown spots on lower leaves. Seen up close, these spots contain concentric rings forming a bull’s eye pattern. Next, the leaves begin to yellow and then to brown, by which time leaves higher up on the plant are showing spots and beginning to yellow. Remove these leaves as soon as they appear and throw them in the trash — not the compost pile. And remember to wash your hands or change your gloves as you move from plant to plant. If you haven’t removed the plant’s leaves 12” to 18” above the soil surface, do so now to promote airflow. Spores of the fungus splash up onto the underside of the leaves, so be sure to keep the plants mulched with a quick-draining material such as shredded wood mulch. Given the conditions this year, you might want to begin a program of weekly spraying about now. According to Bill Adams, author of The Texas Tomato Handbook, early applications of fungicide (copper-based or a broad-spectrum bio-fungicide applied once every 7–10 days) to upper and underside of leaves can reduce the degree of infection. If a half or more of the plant’s foliage has turned brown and the rest is yellow, it’s time to literally bag the plant and put it in the trash, not the compost. You can always try again in the fall with a cherry variety, but be sure to move your tomato to a different part of the garden.
Once temperatures are consistently above 75 degrees at night and the mid-90s during the day, tomatoes will drop their blossoms from sheer exasperation. Smaller varieties, such as cherry tomatoes, are less prone to this. But all tomatoes will produce smaller fruit in these temperatures than they would if planted to set fruit earlier in the summer. Blossoms will also drop when temperatures are below 55 degrees. Poor pollination can occur when the humidity exceeds or falls below the ideal 40%-70% range. If the normal, self-pollinating pattern for tomatoes is disrupted, unfertilized flowers will shrivel and drop.
Gently shake tomato plants occasionally to improve pollination. Excessive nitrogen, lack of water, heavy fruit set or disease pressure can all affect the rate of pollination. Are we having fun yet?
Blossom end rot
This particular condition isn’t a disease but a moody response to prolonged dry or wet weather. It first appears as a small, bruised-looking area at the blossom end of the fruit. These areas become depressed, blackened and tough looking. It tends to affect the first fruits that form during a long period of warm, dry weather — but (not to worry) wet weather can also bring it on. Tomatoes grown in containers are especially prone to this affliction. Apply a form of calcium, such as a spray of calcium nitrate or calcium chloride, to correct blossom end rot. Use mulch to create an even amount of moisture around the plant’s roots and try to maintain an even watering program, providing 1” of water per week. Oh, and if it rains, don’t forget to subtract the rain amount from the required weekly 1”. Several additional rots can plague your tomatoes, but these are the bad boys.
This insect is related to the stink bug and gives off an unpleasant odor when squished. The immature stages (nymphs) of this insect are a quarter-inch long, soft-bodied and bright orange-red in color. Adults are brown, oblong and nearly an inch long. Our local type has a white band extending across the front wings. The hind legs have a leaf-like shape that gave rise to its name. Leaf-footed bugs use their piercing-sucking mouthpart to suck juices from the leaves and fruits of the tomato. While making the puncture, it injects a toxin into the fruit that creates a hard or corky texture. These insects can multiply quickly and then collect in masses on your tomatoes. Brace yourself, go out to the plants in early morning while the insects are still sluggish, and spray the plant with cool water to slow them down. With a gloved hand and a stout heart, grab and squish the bugs. Some gardeners recommend using a shop vac to suck them into oblivion. This sounds appealing, but I’ve never tried it.
The moral of this story is that fresh, home-grown tomatoes are a culinary delight that take blood, sweat and tears to grow successfully. But when you’re able to fend off the birds, the squirrels, the leaf-footed bugs, the blights and the hornworms; when you get the water level right and the fertility balanced; when you avoid sunscald and spider mites — well, then, it’s heaven on earth eating a homegrown tomato with a little salt while it’s still warm from the sun. Buen provecho!