So-called purple tomatoes have been known for a long time. These are mostly heirloom tomatoes, such as Cherokee Purple and Purple Calabash. Their fruit is a dark reddish-brown colour, similar to that of varieties that claim to be black or brown.
Then along came Indigo Rose. This breed is not an heirloom but a hybrid, bred in a laboratory from a purple tomato (a wild tomato species) and a red one. The purple colouring comes from anthocyanin, which increases the level of antioxidants in the tomato. The deep purple colouring is present when the fruit has been exposed to the sun. Parts that are not touched by the sun are green and turn red when ripe.
It is important to note that these tomatoes have not been genetically engineered. The plants and seeds for sale are open pollinated, which means that seed saved from self-pollinated fruit will grow true to type.
The tomato has a good balance of sweet and acid flavours and tastes like… a tomato. The anthocyanin is flavourless so the fruit has the flavour of a red tomato. Cut one in half and it looks like an ordinary red tomato apart from a narrow line of purple where the skin has darkened.
I first saw Indigo Rose seeds on Ebay and thought the pictures had been photoshopped and when I grew some plants this year I was surprised to see tiny dark fruit. Regardless of their immaturity they colour up where the sun reaches them, a sort of muddy brown which darkens as they grow. I found it interesting that in New Zealand’s hot sun the tomatoes look black rather than purple.
These deep purple tomatoes are a novelty to surprise your guests with but it’s the nutrient value, the flavour and the size of the crop that will encourage me to grow Indigo Rose again next year.