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Alaska gardeners always have a lot of questions about their tomato plants. Here are answers.

  • Author: Jeff Lowenfels
    | Alaska gardening
  • Updated: August 13
  • Published August 13

(Bob Hallinen / Anchorage Daily News)

When I say my grandfather grew tomatoes, I really mean it. It was only a hobby, but he still sold about 10,000 plants every spring, and those that didn’t sell, he grew himself. All of my family grew tomatoes. We didn’t think twice about them back then.

Well, I think about tomatoes now. For many Alaska gardeners (me included) they are THE premier edible crop to grow. This is in part because they are easy to grow. They also come in thousands and thousands of varieties, and they have become a staple in our diet, which makes them useful. Most important, a tomato right off the vine beats a store-bought fruit any day!

What really gives growing tomatoes cachet in Alaska, however, is that for the most part they require a greenhouse (though in these days of global warming the lucky can grow some in a sunny, wind-protected location). Requiring a greenhouse makes them part of the Vegetable Royal Family, along with peppers and okra.

I get lots of tomato questions. The most frequent is why someone’s tomatoes are not flowering. Since tomatoes are so easy to grow, many simply plant them without knowing there are two types of tomatoes: determinate (aka bush) and indeterminate (aka vining). So, the answer to the not-flowering mystery depends on which you have. The determinate types flower and produce fruit all in one short period of time, and that is pretty much it, tomato-wise, for the rest of the season. Indeterminate varieties bloom a bit later, but continue to do so throughout the season, even as earlier flowers produce fruit. They will continue as long as the temperature is warm enough.

So, why no flowers? It could be either too early for indeterminate plants, or you have bush types and they are finished growing. Of course, there are lots of other reasons, one being too much fertilizer, especially nitrogen.

How about powdery mildew on leaves? As we hit the rainy season of August, it is important to ensure not only pollination of flowers -- pollinating insects might not fly in wet weather -- but also provide adequate air circulation to prevent powdery mildew. This is a catch-all term for fungal diseases that cause white and gray powder on the leaves. If you have it, get rid of the plants and get a fan ASAP to try and prevent it from taking hold on your other plants.

Some folks are complaining about a deformation known as cat facing. This is a condition evidenced by folds, scarring and deformities at the blossom end of the fruit. No one knows what really causes it. It could be too much nitrogen fertilizer. It could be too heavy pruning. Or thrips hitting the flowers at the right (or wrong) time might be the cause of it. Epsom salt does not cure it. Don’t provide nitrogen if you do feed your plants, and don’t prune anymore!

Then there are all the questions about leaf problems, such as leaves turning yellow and displaying black spots. In fact, I have learned that the list of possible causes for this and other tomato leaf problems is almost endless: Septoria Leaf Spot, Anthracnose, Fusarium, Verticillium Wilt, Early Blight, Late Blight, Mosaic Virus. Similarly, there are any number of reasons why your plants are dropping flowers. Too cool nights? Blossom-End Rot?

I have garden writing friends who make a decent income off of books describing these diseases and many more. You might want to check one or two out. However, if your plants have a symptom, use your computer browser, and describe your problem in your search engine. Or just use”tomato leaf problems” or (tomato bud drop) and scroll through images. You should get some pretty good information on what is ailing your plants.

Finally, yes, it makes sense to grow tomatoes upside down. We stake tomatoes, even the bush types, because without stakes tomatoes would grow as they do naturally, sprawled out on the ground. They are vines. Growing them upside down simply eliminates the need for staking, and fortunately the plant doesn’t care which way it is oriented.

Jeff’s Alaska garden calendar

Potatoes: Don’t stop hilling. Only the tips should remain uncovered.

Lettuces: Harvest when ready. If you wait, they will turn bitter.

Butter and eggs. Egads. It is a bad year. Get yours and toss the flowers.

Watermelon berry (Streptopus amplexifolius). We have more berries than just blueberries! These edible fruits are ready to harvest right now.

Mow a pattern in your lawn contest: Send me your pictures with subject heading “lawn patterns.” Winner gets an autographed copy of one of my books.

Plant a row for the hungry: Don’t let your food go to waste. Share it with those that need it.

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