Minnesota master gardeners test to find top-performing plants

I'm thinking of growing carrots in the raised beds in my back yard this year. But should I grow orange or red carrots? What about purple? Stubby or slender? Should I choose by maturation date, or looks?

My most important question is one the seed catalogs will never answer: How will this plant grow in Minnesota?

Good thing gardeners have another resource — the University of Minnesota Extension Master Gardener Seed Trials. Since 1982, master gardeners around the state have been "trialing" vegetable and annual flower seeds and reporting which varieties perform best overall.

Master gardeners who volunteer for the program plant five or six types of tomato or petunia or whatever plant is being tested. At the end of the growing season, they report which performed best on a variety of measures, including fruiting or flowering, how they held up in bad weather and how much of their seed germinated.

The trials cut through catalog hype with real-life results.

"You can pick up any seed catalog and it will tell you, 'This is the best,' or 'We are thrilled with this,' and you just don't know," said Sue Schiess, a Hennepin County master gardener who chairs the committee that coordinates the trials. "Maybe they make the most profit from it. Or maybe it's the best in Alabama."

Last year, 157 master gardeners in 52 Minnesota counties ran 240 trials of spinach, orange carrots, yellow summer squash, bull's horn sweet peppers, container tomatoes, white alyssum, Shasta daisies and herbs for infusions such as tea. Each gardener grew six varieties of the plants he or she was testing.

It was a challenging gardening year, with a late spring and heavy June rains. In other words, it was very much like our recent Minnesota summers.

Last year's trials showed that what's most popular doesn't always perform best in Minnesota gardens.

A spinach called Olympia outperformed more commonly available varieties such as Renegade and Tyee. Olympia was the most prolific and rated the best-tasting. A majority of testers said they would grow it again.

The winner among orange carrots was Sugarsnax, which was tops in flavor, texture and germination rate. An heirloom variety called Touchon was a close second. More familiar varieties — including Danvers Half-Long and Red-Cored Chantenay — didn't rank as high.

Tumbling Tom and Tumbler were the best-rated patio tomatoes. Tumbling Tom tomato had the highest yield with an average of 57 fruits per plant, and Tumbler was close behind with 50. Tomatoes on both plants had acceptable to very good flavor and 58 percent of the testers said they would grow those varieties again.

Cube of Butter was the top variety among yellow squash, Goccia d'Oro the top bull's horn sweet pepper.

Among flowers, Snow Lady was the top Shasta daisy and Snow Crystals was the top white alyssum. Among herbs for infusions, citronella balm and lemon balm did best.

More complete information on last year's trials can be found in the March/April issue of the magazine Northern Gardener. The 2013 trial results are on the Internet (tinyurl.com/pyfrtwl), but Schiess said she hopes that eventually a more complete list will be on the extension website.

She cautions that because summer weather varies, a plant that performs well one year may not do so well the next. But the master gardener trials are the best measure Minnesotans have for which vegetables and flowers do well in our climate.

"What does it all mean? That is the $64,000 question," she said. "No one can control Mother Nature, and every growing season is different.

"Still, well-educated gardeners have given it their best shot, and these are the results they got. And we can have more confidence because these were grown in Minnesota."

Mary Jane Smetanka is a master gardener and a Minneapolis-based freelance writer.