Carol O'Meara - Colorado State University Extension

Carol O’Meara – Colorado State University Extension

BOULDER COUNTY – When it comes to getting a little slice of love apple in your life, the tomato has come a long way, baby.  From its lowly beginnings as a weed that spread from its native Andean region through Central American into Mexico, the small cherry tomato-sized fruit has won hearts around the world, until becoming a major crop and one of the most popular plants in the vegetable garden.

Tomatoes have been domesticated and improved for size by people throughout history. In the Uto-Aztecan Nahuatl language it was called tomātl, meaning “fat water” or “fat thing”; they also called the bigger, red fruit from their breeding efforts xitomatl, meaning either “plump thing with navel” or “fat water with navel.”

Spanish explorers brought tomatoes to Europe, calling them tomate for the Nahuatl tomātl; Moors living in Spain took the fleshy fruit to Morocco, and from this, the tomato found its way world-wide. Many languages, such as Dutch, Portuguese, German and Ukrainian use forms of the word “tomato” (tomate) to refer to the red fruit, and historical references to it date back to 1595. Other languages, such as Italian and Polish, refer to it as Pomodoro – the apple of gold.

Nicknames abound along with myths about this tasty fruit, including the German “wolf peach” because it was believed that eating a tomato would turn a person into a werewolf.  My favorite is the French endearment pomme d’amore, or love apple.

Once it arrived in Europe, people began tinkering with the tomato, choosing types that performed well in their own locations.  This selection expanded its genetic diversity, providing landraces with a wide array of fruit shapes, colors, and tolerance to growing conditions.

Some of these tomatoes are now popular heirlooms, blasts from the past that provide modern garden treats. Yet over time the inbreeding of types has led to weakness, with some varieties losing vigor and others lowered disease resistance. Some tomatoes lauded in articles and books don’t perform well in every garden, leaving gardeners disappointed in their performance.

To help overcome this problem, growers have taken to grafting tomatoes onto vigorous rootstocks, which lend better growth or disease resistance to the plant. Locally, gardeners have good selection of beloved heirlooms on sturdy roots.

“This region isn’t the best for growing tomatoes.  We have those lovely, cool evenings in summer, which we love but tomatoes hate,” says Sue Parsons, co-owner of Sweetheart Farms, who sell grafted tomatoes at the Boulder Farmer’s market. You can get more fruit earlier on a generative rootstock that puts its energy into fruiting, a handy trait in our short growing season.

“I had a Brandywine set 50 tomatoes on one plant last year,” Parsons said, and one of her customers reported 23 Black Krim set and ripened on his grafted plant while the ungrafted Black Krim grown alongside of it only set one fruit.

Grafted plants cost more because the grower must raise two tomatoes to fuse together, she said, plus some of the grafts don’t take and the plants die. It takes a bit more to bring them to market but the results are worth it.

Caring for a grafted tomato differs from a standard one:  you don’t plant them deeply. Along the lower part of its vine, tomatoes have lumps, called root initials that often develop into roots.  When this happens to a grafted tomato, the genetics of the top growth can take over, reducing or cancelling out the robust characteristics the rootstock provides. Plant them at the same level as they are in the pot, making sure that the graft line – you can clearly see it – is above the soil.

But once planted, treat them like you would other tomatoes and you’ll reap a bounty of love apples.

Colorado State University Extension, together with Boulder County Parks and Open Space, provides unbiased, research-based information about consumer and family issues, horticulture, natural resources, agriculture and 4-H youth development. For more information contact Extension at the Boulder County Fairgrounds, 9595 Nelson Rd., Box B, Longmont, 303.678.6238, or visit