Miss Floribunda: Tomato trouble

The vagaries of weather this summer have done a number on the tomato plants around Hyattsville.

Dear Miss Floribunda,

Last spring I found a full compost bin in the backyard of the house we bought in Hyattsville, so my husband and I started our first vegetable patch. Beans, squash and corn are doing well, but the tomatoes not so good. The plants themselves are large, but we didn’t see any little tomatoes at all until mid-July. We are still waiting for them to get big and red. My older sister, who does not live in this area, has a lot of opinions about gardening, and since we started our patch, she texts advice and IMs pics of her garden. Anyway, she claims our problem comes from not using commercial tomato food but just compost. She thinks compost is giving the plants too much of whatever that first number on tomato food bags stands for, and that makes plants big, and not enough of the middle number, which makes plants have flowers and produce vegetables. When I explained that I’m not into chemistry and think it’s safer to garden organically, she suggested putting Epsom salt on the plants. Even though I know we have a lot to learn, at least I know that salt is very bad for plants and would kill our tomatoes. When I told my sister this, she got salty and said I ought to know that Epsom salt isn’t the same as other salt. When I asked her what difference it makes where salt comes from, and if Epsom was any better than Himalayan salt or Dead Sea salt, she unfriended me. I think she’s stumped.

What do you think could be the matter with our tomato plants, and what do you think we should do?

Uber Organic on Oglethorpe Street

Dear Uber Organic,

Compost is usually well-balanced, and so I’m not convinced your plants are getting too much nitrogen (which is what that first number on the fertilizer bag indicates) at the expense of phosphorus. The second number gives the ratio of phosphorus, the element that promotes flowering and fruiting. The third gives the ratio of potassium, which nourishes a plant’s root system. This is generally referred to as the NPK ratio and is found on every container of commercial fertilizer.

Your sister does understand fertilizer ratios and what they do, but she may not be an organic gardening expert. While tomatoes do need extra magnesium, which is what Epsom salts provide, bone meal is the best natural source for potassium. If you haven’t noticed many flowers on your tomato plants, then there is a deficiency in the NPK ratio of your compost, and you would do apply some bone meal. Also, because she doesn’t live in our area, your sister may not be aware of how the vagaries of our climate are affecting tomato production this year. While most gardeners know that tomatoes won’t set fruit in unusually cool weather, not everyone realizes that extreme heat — temperatures in the 90s day after day — causes the pollen to fry and flowers to fall off before forming fruit. This past July has been sweltering. Daytime temperatures have been well over 90 degrees, reaching as high as 97, and even nighttime temperatures have often been over 80. When cooling rain at last came towards the end of the month, it was torrential and knocked off flowers. In addition, there was a long period when there was little air movement, which also can be a problem for tomatoes. In the absence of bees, tomatoes rely on wind for pollination. Because you’re “Uber Organic,” you doubtless avoid pesticides, so pollinators did visit, and tomatoes developed. You should be getting ripe tomatoes by the time your letter appears in print — although not as many as you might have hoped for. Keep feeding your tomatoes compost and bone meal, and you should get a succession of harvests before frost.

I asked Dr. Agronomosky, soil expert, about Epsom salts. He explained that these salts are unrelated to sodium chloride (NaCl), the salt with which we flavor food, fight fires, preserve food, melt snow, and use in IVs and saline solutions. You are correct that this salt is lethal to most plants. Epsom salts (MgSO4) are chemically known as magnesium sulfate and gets their name from a town in England known for natural springs rich in minerals. Use of Epsom salts does help tomatoes produce larger fruit and more generous yields. Dr. Agronomsky doubts, however, that your soil is deficient in magnesium or sulfur and advises having your soil tested before adding it to your tomato patch.

So although I am only too aware that chemistry can be bewilderingly complicated, it doesn’t hurt to know a few things — such as the NPK ratio in fertilizer and a little something about salts in general. In chemistry, the word “salt” refers to ionic compounds formed by the neutralizing reaction of an acid with a base, often with a metal components. There a great many of them, with complex interactions between what are called cations (positively charged ions) and anions (negatively charged ions), and they form crystals that have many different colors and tastes. Although Himalayan salt is pink, and Hawaiian salt is black, most sodium chloride salt is white and has the taste with which we’re familiar, but other chemical salts come in every color of the rainbow and can taste sweet, sour, bitter or even savory. A good example is MSG (monosodium glutamate), which is so prevalent in restaurant use.

Perhaps you can make peace with your sister and continue to receive gardening information from her. However, as you know, it may have to be taken with a grain of salt.

The Hyattsville Horticultural Society will have a produce swap at its next meeting, Saturday, Aug. 18, at the Hyattsville Municipal Center, 4310 Gallatin Street. The meeting will begin at 10 a.m. You may wish to bring your vegetables and exchange them for other varieties.

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