Blue tomatoes? New varieties to try in your Bay Area garden this year

Gardeners who grow tomatoes have their routines, often growing the same varieties in the same way year after year. But there is change in the world of tomatoes — new varieties and new ways to reduce damage from pests. Here are some recent developments for Bay Area gardeners.

Blue tomato varieties, recently developed, contain the same anthocyanins that are in blueberries. They’re good for you and turn the fruit, or the part of the fruit that gets the most direct sun, deep blue, purplish or nearly black. Even the leaves have a bluish tinge. The first was ‘Indigo Rose,’ a large red cherry tomato that is all blue or blue with some red. It takes 80-90 days from transplant to ripe fruit. There are several faster-developing cherry types. (‘Indigo Cherry Drops,’ ‘Midnight Snack’ and the oddly named ‘Dancing With Smurfs’ are all in the 60-70 day range.) The one with the largest fruit, ‘Indigo Apple,’ has 4-6 ounce fruit with indigo shoulders. It is rated at 70 days, and seed sellers say it has some late-blight resistance.

Another new line of varieties is the Artisan Bumble Bee series, bred at the Green Bee Farm in the East Bay by Fred Hempel, who has stabilized them well enough that they can be called open-pollinated. Their small, often bicolor (striped) fruits were bred for attractiveness and good flavor. At 70-75 days, they are medium-early. Several seed companies sell a mixture of colors and bicolors.

A mix of Pink, Purple and Sunrise Artisan Bumble Bee tomatoes.

Provided by Aaron Whaley

Active breeding also continues to create tomato varieties that resist tomato late blight. This disease, which is spread by spores in the air, not in the soil, has killed many of my tomatoes over the years, turning stems and leaves black and giving fruit greasy-looking, brown shoulders. The best resistant variety I have grown so far is ‘Damsel.’ It’s tall, bearing deep pink, medium to large fruits of exceptional flavor and texture. Also promising is ‘Plum Regal,’ which, at 75 days, is early for a paste-type.

Variety development isn’t the only leading edge in tomato growing. Another is disease control. There are two new microbial pesticides worth trying, both based on ubiquitous, basically nontoxic, soil bacteria.

We had Bacillus subtilis, the active ingredient in the product Serenade, which could be sprayed to manage plant diseases such as rose black spot, rust and powdery mildew, but several years ago it became unavailable.

In place of Serenade, there are new products. One, Revitalize Biofungicide, can be sprayed to manage many diseases, including a number that tomato growers combat. The active ingredient is the soil bacterium Bacillus amyloliquefaciens D747. The label says it has some effect on late blight, though I prefer to seek out resistant varieties (indicated with an LB or Lb after the variety name) when I can. Also it controls leaf spots, botrytis and powdery mildew. Most people don’t see powdery mildew on tomatoes, but several years ago I lost a ‘Sungold’ to that disease. And while I have never seen botrytis (gray mold) on a tomato, I have reports of it in the foggier Sunset District of San Francisco. (I would still pick off botrytis-infected leaves or fruits if I saw the fuzzy gray mold and avoid overhead watering, though I know in the foggiest locations the fog wets plants anyway.)

Even more promising than Revitalize is Actinovate Lawn and Garden, which is based on the soil bacterium Streptomyces lydicus WYEC 108. Not only can it be sprayed on plants but also used as a soil drench. As a spray it will suppress many of the diseases of tomatoes that Revitalize will also suppress. As a soil drench, it will help with the tomato soil-borne diseases fusarium and verticillium. Again, I find it preferable to seek resistant tomatoes (indicated by an F or V after the variety name), but as this is not always possible, I welcome the help.

Finally, new stainless-steel anti-gopher baskets will help protect plant roots from underground varmints. There are now several models, including one made of spun stainless-steel wire that is cheaper and easier to handle than the older-style gopher wire types. (Get one larger than the rootball, and set it lower in soil to protect more roots.)

Note that underground baskets will also protect roots from Norway (sewer) rats, which eat plant roots and are more numerous now than they were pre-pandemic. Rats eat tomato fruit as well, and one could even say rats eating tomatoes is another new trend affecting the crop. (Sigh!)

While anything we can do to discourage rats is good, best would be community awareness, including no outdoor pet food or fallen fruit, no water they can find to drink, trapping when possible, and encouraging municipal use of rat birth-control baits.

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