Farmers Weekly Review

August is upon us, and by now we are over the anticipation of the first tomato of summer, but not this year.

I have had so many questions about why the tomato vines are full of fruit, but they are all still green. And then there are troubles with big bites out of tomatoes, no leaves, and the ever (un)popular brow- to-black, melanoma-looking thing at the bottom of the fruit. Just what is going on here?

Much of what causes tomato problems is weather-related (shocker, right?) But the good news is for several of these problems, the tomatoes are still ultimately edible.

So, let’s start with this year’s biggest problem, tomatoes that refuse to ripen. It seems like it should be just the opposite, it has been so very hot and so early. But that is the reason!

Tomatoes, although a warm-season crop, ripen best at 70-75 degrees, according to Cornell University research. And Purdue says even lower, 68-75 degrees. Lycopene and carotene, the pigments that give tomatoes their color, can’t be produced at high temps. So, the hotter it gets, the slower the ripening — to the point we are now — where ripening has ceased.

If you think about this, it makes sense. It may seem like tomatoes ripen when it is “Satan’s front porch” temperatures. But in reality, the average peak high temperatures in Will County are in mid-July, and when do our tomato crops start filling those bushels? Late July through September is when we are overrun with tomatoes, when our average temps start to decrease.

This year’s heat has slowed that ripening progress. So, what’s a gardener to do? Wait, is the simple answer. If you don’t want to wait, you can harvest tomatoes, but be sure they have started to color up at least a little, like a warm blush. Then keep them at room temperature. Never refrigerate tomatoes, it destroys their flavor and texture.

You can speed ripening on the blushy fruit by putting them in a paper bag with an apple or banana. These fruits give off the ripening agent — ethylene gas — and the tomatoes will ripen up within the week.

But what if your tomatoes are green (or red), and the bottom of the fruit looks like it has bad skin cancer with a black or brown sunken rot spot? This is blossom-end rot, a physiological disease (not pathogen like bacteria or fungus). If you “research” it (which means google these days) it will say due to calcium fluctuation.

But wait!

Will County has plenty of calcium in our limestone-y, often clay soils. It is about even uptake of calcium. Even if you are the best waterer in the county, hot, hot, dry weather followed by flooding rains can cause calcium uptake to fluctuate. But great news! First the red tomatoes with blossom end rot are fine to eat; just cut off the affected section.

Do not go out and buy “blossom end rot preventer.” It is a calcium spray that doesn’t help. As the temps and moisture moderate, blossom end rot will abate. But if you have green tomatoes with blossom end rot already, pull them and compost, because by the time those tomatoes ripen, the rot will have consumed most of that fruit. This will also promote the plants to make more blossoms.

Tomato hornworms are another common problem. How can something as big as a Ball Park hotdog go unnoticed munching on the tomato foliage? But they do. Ah, the glory of nature’s camouflage!

Before you decide to squish them, two things: If they appear to be covered in white, cylindrical eggs, leave them. Again, Mother Nature at work. Those are actually cocoons of tiny parasitic wasps that are eating the caterpillar from the inside out. We want to encourage those beneficials that are bugs that eat pest bugs. Organic gardening at its finest.

The other thing to consider is these large green caterpillars end game. Once they pupate, they become the beautiful evening hummingbird moth. I practice somewhat of a witness relocation program. I keep a few sacrificial tomato plants that I let these caterpillars devour. It is well worth it.

Now for the top of the tomatoes. There are a wide variety of cracks, lines, marks, green “shoulders” that are mostly caused by environmental conditions. These tomatoes are fine to use and just cut off the affected sections.

Gardeners often think tomatoes need sunlight to ripen, so they start pruning off those leaves shading the tomatoes. No, tomatoes ripen by time and temp, and removing those leaves can contribute to that uneven ripening. Leave the leaves. Mulching tomatoes helps alleviate a number of these problems by keeping the soil moisture and temperature more even.

There are some bacterial diseases that affect tomato fruit: bacterial spot, speck and canker. These diseases aren’t seen very often, but they are important, because you should not eat tomato fruit with bacterial diseases.

According to Purdue University, although bacterial speck pathogen is not a human pathogen, the fruit blemishes it causes can provide entry points for human pathogens that could cause illness. You can remove all the affected fruit, and then unblemished fruit are fine.

Treatment for bacterial diseases on tomatoes (both leaf and fruit) contain copper. Be sure to read and follow the labelled instructions for treatment. The irony is just as with fungal diseases, the treatment needs to be applied before symptoms occur.

If you do have bacterial diseases on tomatoes, deep bury, burn (where ordinances allow), or hot compost only the affected plants at the end of the season.

A great resource for vegetable issues of all kinds is Cornell University’s Veg MD Online: http://vegetablemdonline.ppath.cornell.edu/ but I am here too! You can always send me pictures or bring in any plant problems you have [email protected] 815 727 9296.