Tomato -OSU Blue
Bred at Oregon State University, OSU blue fruit develops a rich dark blue-black pigment when exposed to strong sunlight. This colouring is due to anthocyanin pigments, the same as is found in blueberries, black grapes and other similarly-coloured fruits. Anthocyanins are antioxidants and considered a healthy addition to diet. They are not found in ordinary red tomatoes.
Several other blue tomato varieties exist, but unlike many of those, OSU blue was bred using traditional plant breeding techniques (incorporating wild tomato varieties) rather than through genetic engineering.
We have grown this variety for several years now, but only in our poly-tunnel, never outside. We don’t know how it would do, but suspect it is not hardy enough to grow outside in Scotland (although we are currently working on a cross with a very hardy local tomato variety, so we may have an outdoor blue tomato sometime in the future).
We always grow a number of plants together and let them open pollinate, then used the seeds for the following year. Plants are indeterminate and generally grow large with a vigorous sprawling habit (perhaps due to their wild heritage). Fruiting is quite late compared to other tomato varieties so seeds are best started early, but otherwise grow as any indeterminate variety.
As the blue pigment appears where fruits have been exposed to strong light, cutting back leaves to allow light to reach the fruit near ripening time will give more intense blue-coloured fruit.