Determining tomato varieites

The pun in the title is meant to call attention to the growth habit of tomatoes as gardeners pick varieties for planting this month.

Determinate tomato growth ends in a flower while indeterminate types produce vegetative growth and flowers until frost. Of course there are some inbetweens. They are  known as semideterminate types but even that doesn't fully capture growth habits as some are sprawling and some short, upright plants.

Determinate 'Fantastico' F1 hybrid
grape tomato. All-America Selections.

What's the big deal about growth habit other than considering it in allocating garden space, planting distances and staking needs? A lot.

Last time I wrote about the narrow temperature range for pollination of flowers. Determinate types tend to produce flowers all at once and then not many additional ones as they top out. That is great if you want many tomatoes at one time for canning or marketing. It doesn't work out so well if the bulk of flower production occurs during a cold or hot period that is poor for pollination and results in few fruit.

The other consideration is fruit flavor. As Randy Gardner, tomato breeder at the Mountain Horticultural Crops Research station of North Carolina State University, has been noted as saying, the fruit of determinate types will never have the flavor of indeterminate types. They don't produce the ample amount of leaves to photosynthesize and supply fruit that indeterminate types do. He is the breeder of the "mountain" tomato series including 'Mountain Spring' and 'Mountain Merit'. Both are 70-some day to maturity types and are recommended for commercial growers in Colorado.

Mr. Gardner has also said in interviews that his varieties are bred for commercial producers but were adopted by home gardeners in the East when an outbreak of late blight widely took out plants a few years ago. We have little problem with late blight in the dry West, especially if you water at the soil level and keep foliage dry (no overhead sprinklers).

While Mr. Gardner and other plant breeders have bred more disease resistance into their hybrids than heirlooms have, that generally isn't a big reason for choosing varieties here unless you have a problem with TSWV or some other specific disease.

In general I recommend that home gardeners choose indeterminate types or at least a mix of indeterminate and determinate. Even if you want to grow tomatoes for paste you have the choice of indeterminate 'San Marzano' or newer, shorter-season indeterminate hybrids rather than determinate 'Roma'.

Know the growth habit of the variety you are planting as well as the days to maturity (80 days or less in Denver) before purchase.

Photo Credit: 'Fantastico' F1 tomato - All-America Selections

Choosing tomato varieties

The Front Range has varied topography, elevations, location in relation to nearby mountains and microclimates. Every season is different as temperature and rainfall vary through the growing season. A tomato variety that performs well one year may not the next.

For example last season (2016) many people complained that they had few ripe tomatoes by late summer. Summer heat was likely to blame for poor pollination and fruit set. Denver had 44 days from June through August with temperatures over 85 degrees F, temperatures where blossom drop is likely. Greeley had 68 days.

Fortunately we had a fall with extended favorable temperatures so gardeners had time to ripen late-set fruit.

Not only temperatures too high to set flowers but also night temperatures too low are a factor. Our neighbors to the north in Cheyenne had 52 nights in the June to August 2016 period with temperatures under 55 degrees F, poor conditions for pollen viability and pollen tube growth to set flowers. Denver had 16 nights in the same period and Greeley 33.

While it's challenging to choose tomato varieties to grow in our Front Range conditions, the good news is that there are lots of varieties out there and more every year.

My recommendation is for short season varieties (80 days to maturity in Denver, 70 days or less in Cheyenne). Varieties with northern adaptation are also good candidates. These might include Russian heirlooms such as 'Azoycha', 'Aurora', 'Anna', 'Alaska', 'Paul Robeson', 'Black from Tula' or German 'Gardener's Delight' , 'Blondkopfchen' and 'Bloody Butcher'.

Also hybrids such as 'Northern Exposure', 'Juliet', 'Parks Whopper', 'Big Beef', 'Summer Girl' and 'Fourth of July'. New this year is an All America Selection winner 'Midnight Snack', a cherry type that is touted as an advance in flavor for purple types.

Hybrids from crossing heirlooms are also gaining popularity and include 'Brandy Boy,' 'Big Brandy', 'Genuwine' and 'Perfect Flame'.

I also recommend a mix of varieties including both heirlooms and hybrids. Chances are that if one doesn't perform well under this year's weather conditions, another will.

Photo credit: Windowsill tomato starts - Carl Wilson

New Vegetables for 2017

'Patio Choice Yellow' tomato

Got small spaces? 'Patio Choice Yellow' F1 tomato may be right for you.

An All-America Selections winner, this tomato is a compact, determinate plant growing only 15 to 18 inches tall. It's the perfect size for container growing on a balcony or other small space.

Vines can bear 100 fruit and begin bearing in only 65 days from sowing seed.  The 1 inch bright yellow fruit are mildly sweet with a touch of acid.

'Antares' F1 bulb fennel

Why not try something new in your garden this year? 'Antares' F1 fennel not only produces an edible bulb, it's fine textured fronds are very ornamental in the garden. You can grow the plant for its culinary seed and it is also a favorite food for swallowtail butterflies and other pollinators.

The bulbs are said to have an improved, almost sweet licorice-anise flavor as compared to other market varieties. It is also a week slower to bolt.

Fennel is a warm season vegetable that will grow bulbs 4 to 5 inches in diameter and foliage 24 inches tall. Grow in rows 6 inches apart with 24 inches between rows. The plant is ready to harvest 68 days from sowing seed or 58 days from transplanting. Plants can be grown in a container if desired.

Photo credit -  All-America Selections

Varieties Adapted to Front Range Colorado

Amy's Apricot tomato

Cherry tomatoes are convenient for many people and golden cherry tomatoes have been of interest. Sun Gold is one that seems to do well in Denver and has become popular.

This year I tried another heirloom, Amy's Apricot, that did equally as well and has excellent flavor. An indeterminate type like Sun Gold, the only concern for some may be that Amy's Apricot is is 10 days later at 74 days versus Sun Gold at 55 to 65 days. Tomatofest.com carries Amy's Apricot seed.

Caroline fall bearing raspberry

Switching to small fruit, your fall bearing raspberries should be yielding well by now. If you are still growing Heritage red raspberry, consider switching to an earlier bearing variety when you pull out plants (generally necessary due to virus buildup after 10 years or so).

Newer fall raspberry varieties such as Caroline, Jaclyn and Autumn Britten bear fruit 2 weeks earlier. Late bearing Heritage has always been problematic with coming into bearing when frost danger may threaten in mid to late September.

Fall bearing raspberries are generally recommended in Colorado because they bear on first year canes; you don't need to worry about winter-kill of canes or buds as you do with summer bearing types that don't bear until their second year. Fall bearing types are easy for pruning too because canes are cut to the ground every year in December/January and regrow to produce a crop the next season.

Photo credit: Both photos credit Carl Wilson

Tomato taste information for seed ordering

With all those seed catalogs arriving, lots of tomato varieties look tempting. Which ones taste the best?

A taste test last season in Boulder, Colorado identified some favorite tomatoes. Among 40 salad tomatoes including low-rated 'Celebrity' and 'Stupice', 'Siberian' came out on top with 'Carmello' and 'Cosmonaut Volkov' close behind. Those were followed by 'Jetsetter', 'Green Zebra', 'Early Girl' and 'Valencia' that formed a respectable second tier.

For beefsteak types, the winners out of 23 compared were far and away 'Pineapple' and 'Amana Orange'. Those receiving respectable but far fewer votes were 'Paul Robeson', 'Cherokee Purple', 'Black Krim', 'Black Sea Man', 'Brandywine' and then 'Black from Tula'.

Thirty-one cherry types were taste tested with the winners 'Sungold' followed by 'Yellow Globe', 'Isis' and 'Green Doctors Frosted'. The second tier included 'Matt's Wild Cherry', 'Chiapas', 'Yellow Pear' and 'Green Doctors'. Respectable ratings were given to 'Wow', 'Sweet 100', 'Sunsugar' and 'Black Cherry'.

Eight paste tomatoes were in the test with 'Plum Zebra' winning by far. And yes, standards 'San Marzano' and 'Roma' were in the test but rated very low.

This test will tell you something about how a group of people rated the taste of tomatoes grown locally. It says nothing about how productive, how early, or how disease or crack resistant these varieties are to name a few things you might be looking for. Keep in mind your own production needs when choosing seed to plant.

Photo Credit: Tomato fruit in bowls - Carl Wilson

Banner year for tomatoes

Although many people on the Front Range may be tired of summer heat, there is always a plus side. One is that it has been a banner summer for productive tomatoes. This is due to hot days but more so to warm nights. Many nights have been in the sixties degrees F instead of fifties as is so often the case in Front Range summers.

After a cool May and transplanting better delayed until the first week in June, some people were despairing of realizing a tomato yield due to a late start. This has obviously resolved itself and many varieties are showing good performance.

In full sun, 80 day heirloom 'Cherokee Purple' in our garden is doing as well as 73 day modern 'Big Beef'.

Three short season varieites tried this year are of note. 70 day 'Azoychka' from Russia (photo above right) is a mild acid, yellow fruited type that is producing well. A 68 day pink Asian type, 'Zhefen Short' (photo left) from China is yielding a good crop of nice plump fruit. The heirloom 75 day 'Black Cherry' (photo right) is also bearing nicely.

Shorter season types of 70 days or less including 'Early Girl' (62 days) and heirloom 'Stupice' (52 days) from Czechoslovakia (photo right) are still good bets especially if you have only part day sun or a cooler location. They bear early and can perform well in summers that don't have warm nights. Both have produced well for us this year.

Harvest from the demonstration garden at our Denver office is donated to feed the hungry. Consider donating your excess bounty to a local food pantry or soup kitchen.

Photo credit: 'Azoychka', 'Zhefen Short', 'Black Cherry', 'Stupice' tomatoes - All Carl Wilson.