Researchers at Colorado State University’s Master Gardener program have finally settled the age-old question of which tomatoes and peppers grow best in Northern Colorado, where the growing season is notoriously short and difficult.
Their answers are the result of five years of field experiments that took root in a garden bed in northeast Fort Collins, coordinated by Master Gardener volunteer and retired seed breeder Jon Weiss.
While most moderately skilled Colorado gardeners can certainly eke a crop out of hundreds of tomato and pepper varieties, Weiss said that a knowledge gap persisted about which of those varieties perform best under the unique climatic conditions in the greater Larimer County area.
“We retired here in 2016 and one of the questions I started looking up is what kind of tomato varieties can you grow here? And I really couldn't find any solid information on that topic,” Weiss said. “You can read seed catalogs all you want. But the key to any of this is to trial them out, compare varieties to varieties, plant types, two different types of tomatoes, and see what does well here.”
CSU Extension Professor of Horticulture Alison O’Conner, who was also involved in the trials, said that Northern Colorado’s unpredictable weather can cause most varieties to struggle. “With the wind, with our increasingly high summer temperatures, with the potential for hail always looming, we just face a lot of different conditions.”
Out of 15 tomato varieties the researchers tested, 2 types stood out. An indeterminant red variety called New Girl withstood the harsh climate with grace.
“It was the earliest, the best tasting, and one of the highest yielding tomatoes in the trial,” Weiss said.
A compact yellow cherry tomato called Patio Choice Yellow was also a top performer.
As for the sweet peppers, two bell pepper varieties, Ace and Olympus had the best outcomes, along with a smaller, lunchbox pepper, the Just Sweet.
“It's kind of an orange color, a lot of fruit, great flavor,” Weiss said of the latter. “Most of the [pepper] plants don't exceed 24 inches in height, so they're quite manageable in in any kind of environment.”
Weiss said the team hopes the trials will give Northern Colorado gardeners a little more information to work with when planning out their gardens for the next season.
“Most homeowners just want to have a nice juicy red tomato at the end of the day from their plants, that they grew in their own garden,” he said. “That's all we're trying to do is help them to reach that goal.”
“We want to make sure that people who are investing time and energy growing plants do get to harvest fruit,” O’Conner added.
O’Conner cautioned that the trial results are hyper-local and specific to the greater Larimer County area. Other parts of Colorado might favor different varieties – that research hasn’t been done yet.
“We hope this encourages other potential Master Gardener programs or extension programs to try to do some more local research,” O’Conner said.
The team has some work to do to popularize the best performing varieties, which, when it comes to the tomatoes at least, have not been widely available as transplants from local garden centers.
“We're trying to encourage our garden centers to look at our results and ask the simple question: ‘well, if this is doing well in the trial, why not try offering some of these varieties to our public?’” Weiss said.
The Master Gardener Larimer County vegetable trials will continue into the next season. Now that the question of tomatoes and peppers has been put to bed, the team will turn their attention to winter squash and cut flowers that do well in Northern Colorado’s unique terrain.
