Love the color, shapes and tastes of heirloom tomatoes? Master Gardener, Fred Hoffman explains a few important rules to remember when finding, saving and storing your favorite heirloom tomato seeds.
Growing Heirloom Tomatoes…in the Winter!
If you really want to demonstrate to your friends what a great investment your greenhouse is, nothing beats serving them home grown heirloom tomatoes, on New Year's Day!
Here's What You'll Need to Grow Greenhouse Tomatoes for the Winter and Spring:
The Right Tomato. For the typical hobby greenhouse (8x5, 8x10, 8x12), cool season "determinate" tomatoes are best. These tend to be fairly compact plants (under 4 feet tall) that do not put on lots of growth after they set fruit. Determinate tomatoes usually ripen at the same time; so, choose several tomatoes that will ripen at different times, going from seed to fruit in 50-70 days.
A "Warm Greenhouse". This is one that maintains a nighttime temperature range of 55-70 degrees, preferably above 60 degrees for tomatoes. Daytime temperatures should range from 75-85 degrees. A heater, in conjunction with a thermostatically controlled vent fan, can easily provide that temperature range throughout most of California.
Sunlight. Tomatoes need full sun, at least six hours of direct sun a day. Try to position your greenhouse so that it can take best advantage of the low angle of the sun during the cold months, making sure the building isn't shaded by any evergreen trees or other structures.
Artificial light. Because of the lower intensity of the sun and the persistence of valley fog and low clouds during the winter, you may need a lighting system to supplement the natural light. Although there are many artificial lighting systems available, fluorescent lights are the most economical. Use four, 40-watt, 48-inch long fluorescent tubes side by side, keeping them 8-12 inches above the plants. Although standard "shop lights" are OK, investing in Gro-Lux wide spectrum fluorescent tubes will give your tomatoes more of the light spectrum that they can use.
Water. Although the cooler temperatures of the fall and winter will cut down on the amount of water that tomatoes need, a drip system connected to a timer will insure that the plants get the moisture they need. Four to eight gallons of water per week per plant should be plenty.
Soil. Planting directly into the ground of the greenhouse is OK, as long as the soil drains readily, has been amended with organic matter and isn't compacted. Building raised beds into the floor of your greenhouse works best. Make the sides of the raised bed 8-16 inches high, and at least 18 inches wide. The bed can be framed by a number of things, including untreated wood, blocks, bricks, or stacked old tires. Growing tomatoes in plastic 5-gallon pots and half-barrels work well, too.
Fertilizer. Because plants tend to slow down their growth in the colder months, cut your dosage of your favorite tomato fertilizer by half. For example, if the directions for a water-soluble fertilizer say to add 1 tablespoon per gallon of water, pour that same tablespoon into 2 gallons of water during the winter feeding periods. A once-a-month application should be plenty.
A Pollinator. In nature, bees and wind do most of the tomato pollination in the home garden. In the greenhouse, you can accomplish the same task by either gently shaking or holding an electric toothbrush next to the plant; or, twirling a small brush inside a tomato flower to transfer the pollen. Also, a small fan gently blowing across the plants can help tomato plants pollinate themselves as well as help build sturdier stems.
Some greenhouse tomato heirloom variety suggestions for the colder months:
Manitoba. The fruit is over 6 oz. in size, very productive and early. Determinate, 60 days.
Glacier. Cold tolerant and productive. Tomatoes are over an inch in diameter. Determinate, 58 days.
Grushovka. A pink, egg-shaped, 3-inch long tomato from Siberia. Plants are under three feet tall. Determinate, 65 days.
Clear Pink Early. 2-3 foot tall plant produces pink tomatoes, about 3-6 oz. Determinate, 58 days.
Polar Baby. Developed in Alaska. 2-inch salad tomatoes. Determinate, 60 days.
Prairie Fire. 3-5 oz. tomatoes on short plants. Tangy flavor. Determinate, 55 days.
Red Robin. The plants get only 12 inches tall, producing cherry-sized tomatoes. Good choice for hanging baskets. Determinate, 63 days.
Siberia. A favorite of Canadian greenhouses, this bushy plant reportedly will set fruit at temperatures as low as 38 degrees. Fruit is under 2 inches in diameter. Determinate, 55 days.
The following are not heirloom tomatoes, but do well in winter greenhouses:
Oregon Spring V. Developed at Oregon State University for short season gardens. Medium sized fruit that is nearly seedless. Determinate, 58 days.
Siletz. 10-12 oz. tomato developed in Oregon. Determinate, 52 days.
Sub Arctic Maxi. For very cold climates. 2 oz. fruit on a small plant. Determinate, 62 days.
Sweet Tangerine. Orange-red colored fruit. Determinate, 68 days.
Tumbler. Cherry-sized tomatoes in seven weeks. Good choice for hanging baskets. Determinate, 49 days.
506 Bush. Plants only get 18 inches tall, are drought tolerant and produce medium sized tomatoes. Determinate, 62 days.
Bush Early Girl VFFNT Hybrid. A bushy plant that produces 6-7 oz. fruit. Determinate, 54 days.
Bush Beefsteak. The fruit averages 8 oz. each on a compact plant. Determinate, 62 days.
Pilgrim VFFA Hybrid. 8 oz. fruit on a compact plant that boasts excellent yields and good flavor. Determinate, 65 days.
rest of Episode 915