OSU Blue Tomato

Over the winter Colleen from In the Garden Online offered me OSU Blue tomato seeds. Having never heard of this tomato variety and seeing how cool the fruits looked I figured I’d give them a try. Yes, there is a blue tomato and it is as unusual a tomato as you imagine and will see below. My first experience with these tomatoes was trying to get the seeds to germinate, a task that seemed so daunting I was about to throw them away before I noticed the seeds had sprouted. This blue tomato was developed by Jim Myers, OSU's Baggett Frazier professor of vegetable breeding and graduate students Carl M. Jones and Peter Mes. The first thing you should understand about the OSU Blue tomato is that it wasn't developed using genetic engineering, but using traditional plant breeding techniques.

Garden helper holding OSU Blue Tomatoes.

When ripened, the fruits of OSU Blue range from purple, blue to a dark, almost black color. Probably the closest to black and purple you’ll ever see in a tomato. ‘Black Prince‘ and ‘Purple Cherokee’ tomatoes have got nothing on OSU Blue tomatoes in terms of color. Professor Myers and his students crossed a domestic tomato plant with the genetic stock of a tomato that included a gene incorporated from a wild relative with anthocyanin-containing fruit to produce a healthier tomato. Anthocyanins are the same class of compounds that produce the healthy pigments in red wine that work as antioxidants. According to Myers, domestic tomato varieties grown and consumed in the United States do not normally produce fruit containing any anthocyanin. Anthocyanins are the same class of compounds that produce the healthy pigments in red wine that work as antioxidants. While other fruits have higher concentrations of anthocyanin (think blue berries); the thinking behind adding them to tomatoes is that more people will be exposed to them. Tomatoes are second only to potatoes in consumption of fruits and vegetables. Americans eat about 90 pounds per person per year of fresh and processed tomatoes according to Peter Boches and Jim Myers, Department of Horticulture, Oregon State University.

Green side of OSU Blue tomato not exposed to sun

Anthocyanin is only produced in the fruit in areas that are exposed to sunlight. If the fruit is shaded by a leaf, stem or calyx that part of the fruit will remain green. I noticed that the blue pigment only developed in the top half of tomatoes growing lower on the vine. Intense sunlight lead to the most beautiful purple color; since only the part of the OSU Blue exposed to sun turned purple I would bend the stems in half so sun would reach the bottom half of the tomato. Late in summer there was a dip in temperature that also intensified the color.

OSU Blue tomato: purple on the left and red/purple on the right.

The parts of the fruit that weren't exposed to direct sunlight remained green until the fruit passed the ideal ripe stage and then the green skin turned a red-orange color as illustrated by the picture of the OSU Blue tomato above. According to  Boches and Myers, the genes involved in producing the OSU Blue tomato, Aubergine (Abg), Anthocyanin fruit tomato (Aft) and atroviolaceae (atv), are genes introgressed from the wild species Solanum lycopersicoides, S. chilense, S.cheesemanii, respectively. Honestly, I don't know what any of that means, but I can tell you that when OSU Blue tomatoes are at the purple stage pictured above they look similar to the purple tomatillos I grow in my garden.

OSU Blue tomato compare to purple tomatillo

Unlike the OSU Blue tomatoes grown by Gayla Trail last year my OSU Blue tomatoes didn't produce purple stems and foliage. It seems like a lot of tomato growers are growing this tomato, sometimes known as similar in appearance to Blue P20, and doing some experimenting with crossing it with other tomatoes.

Here's a video of the OSU Blue tomatoes at the end of the season in my garden.


Overall OSU Blue may be the most unusual tomato I have ever seen The color is absolutely beautiful and unlike any tomato I've ever grown before in my garden. The flesh of the tomato isn't as dark as the skin and the over-ripened tomato you see pictured above had red flesh when I cut into it. Other OSU Blue tomatoes ranged from green to purple depending on their ripeness. While these tomatoes may be healthier their taste leaves a lot to be desired. It wasn't bad, but it wasn't great either. I'd grow these tomatoes again just for their looks the blue tomatoes ripening to an almost black color are certainly conversation pieces in the garden. Unfortunately, my batch of OSU Blue tomatoes weren't very seedy and I didn't manage to save seeds from them which is disappointing. If you're new to tomato seed saving see my post on How To Save Tomato Seeds.

Sources: OSU researchers add potential helth benefits to tomatoes/OSU Blue tomato FAQ (PDF).