Black tomatoes were first bred by Professor Jim Myers at the University of Oregon, during a graduate study about the health benefits of tomatoes. When they discovered that purple tomatoes contained anthocyanin, which also provides colour to blueberries, they decided to cross them with some wild red ones. Eventually, they came up with a black strain.
'Indigo Rose,' was released in 2012 and, according to Myers, "It is the first improved tomato variety in the world that has anthocyanins in its fruit."
Since 2012 a number of distinct 'Indigo' varieties have been produced. The Indigo series is creating a new class in tomatoes, and changing the face of the tomato world. Not only are they extraordinarily colourful and tasty, they are extra nutritious. Developed with traditional breeding techniques, the fruit of these unusual varieties contain high levels of anthocyanin, a naturally occurring antioxidant found in blueberries, and is reported to combat disease. Anthocyanin reveals itself in the vibrant indigo pigmentation of the fruits. Each of these varieties has unique characteristics, and all are stunningly beautiful.
'Indigo Blue Berries' is a development from 'Indigo Rose', Heavy sets of unripe fruit show lots of purple due to the high anthocyanin level, the same powerful antioxidant found in blueberries. Their appearance is striking enough to turn heads at farmers’ markets or become the centerpiece of a home garden.
Indeterminate plants produce trusses of the delightfully delectable little, 12 to 16 grams (1 to 2oz), cherry sized tomatoes. The unripe fruits are amethyst purple and ripen to almost black, with a brick red blossom end and delicious plum-like flavour. 75 days to maturity.
As they cannot tolerate any degree of frost the timing for sowing and planting outside is key to successfully growing tomatoes. Where the seeds are sown under cover or indoors, aim to sow the seeds so that they reach the stage to be transplanted outside three weeks after the last frost date. Tomato plants take roughly seven weeks from sowing to reach the transplanting stage. For example, if your last frost date is early May, the seeds should be planted in early April to allow transplanting at the end of May.
Tomatoes require a full sun position. Two or three weeks before planting, dig the soil over and incorporate as much organic matter as possible. The best soil used for containers is half potting compost and half a soil-based type loam: this gives some weight to the soil.
Plant about 3mm (1/8in) deep, in small pots using seed starting compost. Water lightly and keep consistently moist until germination occurs. Tomato seeds usually germinate within 5 -10 days when kept in the optimum temperature range of 21 to 27°C (70 to 80°F). As soon as they emerge, place them in a location that receives a lot of light and a cooler temperature (60 to 70°F); a south-facing window should work.
When the plants develop their first true leaves, and before they become root bound, they should be transplanted into larger into 20cm (4in) pots. Young plants are very tender and susceptible to frost damage, as well as sunburn. Protect young plants by using shade netting or placing a large plastic milk jug, with the bottom removed, to form a miniature greenhouse. Depending on the components of your compost, you may need to begin fertilising. If you do fertilise, do it very, very sparingly with a weak dilution.
Transplant into their final positions when they are about 15cm (6in) high. Two to three weeks prior to this, the plants should be hardened off.
Just before transplanting the tomato plants to their final position drive a strong stake into the ground 5cm (2in) from the planting position. The stake should be at least 30cm (1ft) deep in the ground and 1.2m (4ft) above ground level - the further into the ground the better the support. As the plant grows, tie in the main stem to the support stake - check previous ties to ensure that they do not cut into the stem as the plant grows.
Dig a hole 45cm (18in) apart in the bed to the same depth as the pot and water if conditions are at all dry. Ease the plant out of the pot, keeping the root ball as undisturbed as far as possible. Place it in the hole and fill around the plant with soil. The soil should be a little higher than it was in the pot. Loosely tie the plant's stem to the support stake using soft garden twine –allow some slack for future growth.
A constant supply of moisture is essential, dry periods significantly increase the risk of the fruit splitting. Feed with a liquid tomato fertiliser (high in potash) starting when the first fruits start to form, and every two or three weeks up to the end of August. In September, feed with a general fertiliser (higher in nitrogen) in order to help the plant support it's foliage.
Over watering may help to produce larger fruit, but flavour may be reduced. Additionally, splitting and cracking can result from uneven and excessive watering.
When the first fruits begin to form, pinch out the side shoots between the main stem. Also remove lower leaves which show any signs of yellowing to avoid infection.
Harvest tomatoes as soon as the fruits are ripe, when they are fully coloured and firm, this also encourages the production of more fruit.
About a month before the average first autumn frosts, clip all blossoms and any undersized fruit off the plant. This will steer all the plant’s remaining energy into ripening what’s left.
If you have a lot of under ripe tomatoes near the end of the season, and a frost is approaching, pick them and store them indoors in a single layer away from direct sunlight to ripen.
- Additional Information
Packet Size 10 Seeds Common Name Black Cherry Tomato
Vine / Cordon (Indeterminate)
Family Solanaceae Genus Lycopersicon Species esculentum Cultivar Indigo Blue Berries Hardiness Half Hardy Annual Fruit 3cm (1in) fruit Height 150cm (60in) Spacing 60cm (24in) Season 70 days to maturity Time to Sow Early April to End May Time to Harvest 75 days to maturity