Big Rainbow Tomato

Solanum lycopersicum (nightshade)

A visually spectacular heirloom that had been grown quietly for generations as a family variety in Polk County, Minnesota, before being shared with Seed Savers Exchange in 1983 and offered commercially from 1990. Huge, ribbed beefsteak fruit ripens into a genuine rainbow of colour — green shoulders giving way to gold and orange through the middle, with dramatic red streaks and blushing radiating from the base — and the golden-orange flesh inside is just as striking when sliced. Mild, sweet, and fruity rather than sharply acidic, it's as much a showpiece for the table as it is a good eating tomato. Indeterminate (climbing) variety — requires sturdy staking.

Days to harvest 85–90 days from transplant
Fruit size 700–900g+, ribbed beefsteak shape
Sowing depth 5mm
Germination 6–14 days at 24–29°C
Spacing 60–90cm apart
Aspect Full sun, well-drained soil
Frost tolerance Frost sensitive — needs reliably warm nights

Growing notes

Choose a full-sun, open position with good air circulation. A big, vigorous plant with dense foliage that naturally helps shield fruit from sunscald. Needs a substantial pot from 40L+ with strong staking

Soil preparation: Rich, well-drained soil with plenty of organic matter worked in.

Support: Sturdy staking or a strong cage essential — vines can reach 1.8m and fruit is genuinely heavy.

Watering & feeding: Water deeply and evenly, avoiding both extremes of dry and overwatering — inconsistent watering can cause cracking. Feed regularly with a potassium-rich fertiliser once flowering and fruiting begins, avoiding excess nitrogen.

Harvest: Pick once the colour pattern has fully developed — green shoulders are normal on this variety and don't indicate under-ripeness elsewhere on the fruit.

Timing: A later-season variety — expect first harvest around 85–90 days after transplanting, with production building later into summer.

Key features

  • Open-pollinated heirloom, from Polk County, Minnesota
  • Huge, ribbed beefsteak fruit, often 700g–900g+
  • Striking bicolour skin — gold, orange, and red
  • Golden-orange marbled flesh
  • Mild, sweet, fruity flavour
  • Dense foliage helps protect fruit from sunscald

Short season tips

Sow 6–8 weeks before you want to plant out, on a heat mat if possible — soil needs to be 24–29°C to germinate reliably. Being a later-maturing type, an early, warm start pays off in giving it the longest possible season to reach full size and colour. Transplant only once all risk of frost has passed and nights are reliably mild.

  • Spring
  • Summer

Tender perennial — most often grown as an annual

  • Basil (classic tomato pairing) Marigolds Carrots Parsley
  • Other nightshades (capsicums, chillies, eggplants, potatoes) Fennel Corn

Grown for generations as an unnamed family heirloom in Polk County, Minnesota, before Dorothy Beiswenger of Crookston shared the seed with Seed Savers Exchange in 1983, giving it the name Big Rainbow for its striking colouring. It was offered commercially from 1990 and remains one of the most popular bicolour tomatoes among heirloom growers, prized as much for its beauty on the plate as its flavour.