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Indigo Rose Tomato Trial

Photo by Susan MacDonald

Click here for printable (PDF) verison of the report.

Submitted by Janet Didur, Master Gardener, 2008

Statement of Intent:  The intent of this study was to test the vitality, productiveness and palatability of Indigo Rose tomatoes grown under a variety of conditions throughout the Bay Area.  I would like to acknowledge the volunteers who grew and reported back to me on the results of their tomato trials.  Without their kind help, I could not have produced this report.  My sincere thanks.

Background:  The Indigo Rose tomato was bred at Oregon State University with the intention of creating a variety with high levels of antioxidants.  It was developed for home gardens and farmers markets.  Indigo Rose is the first improved tomato variety in the world that has anthocyanins in the fruit.  Anthocyanins are in the class of flavonoids, compounds found in fruits and vegetables, which are high in antioxidants.  It is uncertain at this point whether the antioxidants observed in the test tube have an antioxidant effect in the human body.

Breeding for Indigo Rose began in the 1960’s when a Bulgarian and an American researcher crossed cultivated tomatoes with wild species from Chili and the Galapagos Islands.  Some wild species have anthocyanins in their fruit.  Domesticated species, until now, have only had this beneficial pigment in their leaves and stems, which are inedible to humans.

Blueberries contain more anthocyanin than Indigo Rose tomatoes.  However, as tomatoes are eaten by Americans on almost a daily basis, the health benefits of antioxidants from these fruit could have a profound effect on the health of our population.

Methodology:  Twenty Indigo Rose seeds purchased from Territorial Seed Company (see Note 1 below) were planted on March 12, 2012 in 1-inch cells using Lyngso Organic Vegetable Blend with endomycohhrizal fungi.  Propagation was 100%.  Seedlings were up potted into 4-inch containers on March 23, 2012.  The tomatoes were up potted on April 20, 2012 into one-gallon containers.

Notice was sent to the Master Gardener community and friends soliciting volunteers to participate in the study by growing the Indigo Rose at their homes, observing and keeping records of the progress of the plants.  Including myself, eleven people participated in the study.  Questionnaires were sent out to the eleven participants mid October.  Six responses were received.

Results: Of the six respondents, three planted the tomatoes directly into the ground, one in a raised bed and two were in containers.  Some people took multiple plants.  Dates of planting ranged from end of April through mid May.

Ground and Raised Bed Planting:

Space between plants Type of Soil Soil Amendment Fertilizer Location
2 feet native clay none

Miracle Grow Spray initial planting and mid-July

Full sun
3 feet Loam Personal Compost and Worm Casings Worm Tea once a week South facing against house & out of wind
2 feet Mulch and loam 1/2 compost none Southwest facing, shaded from hottest sun
18 inches Loam Point Reyes compost mango mulch, Happy Frog (7-4-5), 2 tsp. one month after planting East facing adjacent to fence

Container Planting:

Size of pot Type of Soil Soil Amendment Fertilizer Location
20 gallon Miracle Grow Organic Potting Mix none none South facing against a fence, reflective heat
15 gallon Lyngso Organic Vegetable Blend none Alfalfa pellets applied mid-June Green house, south facing

Flowers were observed in mid-May.  Date of first fruit and harvestable fruit varied, as did average fruit size.  Please note the differences between climate zones on fruit size.

Ground and raised bed planting:

Sunset Garden Climate Zone First Flower First Fuit Number of Fruits Harvested Size of Fruits
17 (Santa Clara) Early May Mid-May 100 per plant 2 inches
17 (Foster City) Early August Mid-August 60 per plant (still harvesting late October) 1 1/2 inches
15/16 (Menlo Park) Not recorded Not recorded "lots" 2 inches
14 (Antioch) Mid-Mad Late May Over 75 per plant 1 1/2 - 3 inches

Container Planting: 

Sunset Garden Climate Zone First Flower First Fruit Number of Fruits Harvested Size of Fruit
15/16 (Atherton) not recorded Mid-June Over 70 1 1/2 inches
17 (Moss Beach) Early May Mid-June Over 100 (still harvesting mid-November) 1 1/2 inches

Verbatim comments on the Indigo Rose tomato follow:

-Hardy and healthy, productive longer than all the other varietals.
-Vigorous, some leaf curl.
-One plant produced split fruit.
-Vigorous, strong.
-Resistant to mold which attacked other tomato varietals.

-Beautiful!  Bright purple firm fruit hanging in clusters
-Bushy and sprawling.
-Very attractive
-Green, wild, curly leaves
-Gorgeous plant.  Real conversation piece.

Taste of Fruit
-Sweet, non acidic
-Great in sauces, even the skin.
-not very juicy, not very sweet
-clean, clear flavor

How did you use the fruit?
-Fresh and in tomato sauce
-loved it cooked in sauces
-in salads
-Salads and omelets
-salad, pasta sauce, omelet, cheese platter, raw vegetable platter, soup

Would you plant Indigo Rose tomatoes again?
-Absolutely!  Fruit is beautiful, good tasting and plants yield tons of fruit (zone 17)
-Yes, they taste good cooked and the fruiting season is long.  Not ripening on the vine due perhaps to a cool summer? (zone 17)
-Yes for aesthetics.  This is a show-stopper for looks on bush and table. (zone 15/16)
-I enjoyed these tomatoes and would certainly grow them again.  They last a long time.  I’m still producing tomatoes in October. (zone 14)
-Maybe for color but not at the expense of other plants. (zone 15/16)
-Yes indeed for taste, color and health! (zone 17)

Summary:  Indigo Rose tomatoes can successfully be grown in both containers and directly into the ground.  They are hardy, disease resistant and given sufficient heat and/or protection from cold winds, prolific producers.

It is important not to pick the tomatoes too soon.  Indigo Rose must be allowed to ripen fully for complete development of sugars and acids. It's easy to harvest too early because the usual visual clues won't be there.

The fruits start off green, and become purple where exposed to light.  They tend to have a purple crown. They are ripe when their color changes from a shiny blue-purple to a dull purple/red-brown. The fruit also softens similarly to regular tomatoes, and the bottom of the tomatoes will turn from green to red when ripe.

Anthocyanin produces in the fruit only where exposed to sunlight. If shaded by a leaf or on the base, the purple pigment does not develop.  If you pick an Indigo Rose and expose the non-purple area to sunlight, it will turn purple in about a week.

Conclusion:  Whether you will enjoy the taste of Indigo Rose is personal.  They are not beef steak tomatoes, nor do they try to be.  If you are expecting juicy and sweet this is not your tomato.  If you are interested in a clean, clear flavor, a satisfyingly dense texture, a ‘show-stopping’ appearance and potential antioxidant producing health benefits, this is your tomato!


For more information, please contact the Master Gardener Help Line at (650) 726-9059 ext. 107.

Note 1: At this time, seeds may also be purchased from Nichols, High Mowing and Johnnys Seeds.  Indigo Rose is an open pollinated variety, which means that if you choose to save your seeds from self pollinated plants, they will grow true and not produce hybrids.