Paul Vossen is a Farm Advisor, Sonoma County Cooperative Extension
Lycopersicon lycopersicum (esculentum) is a member of the nightshade family.
The tomato plant is native to tropical America, but has been cultivated in Europe and the United States for more than 200 years. There are about 400 varieties available commercially today. Many older varieties have been lost, but breeding programs continue to add new varieties each year. Many of the varieties described here are old varieties that are carried by only a few seed companies.
Current production and yield
In 1990 fresh-market tomatoes were farmed on 38,000 acres in California, producing almost 1 billion pounds. An average of 1,275 flats (about 20 pounds each) were produced per acre. The average price per flat was $5.64.
Fresh-market tomato consumption in the United States in 1988 was 14.7 pounds per capita. High-volume tomato production and marketing are significantly influenced by price, and competition is fierce. Varieties are selected for yield, tolerance to shipping, fruit size, fruit color, ripening date, and pest resistance.
Consumers are most familiar with red tomatoes that are harvested at a mature green stage and allowed to ripen off the vine. There is a market opportunity for flavorful, vine-ripened fruit of many colors as specialty items sold for their uniqueness. Out-of-season tomatoes sold from November to May also command significantly higher prices.
The tomato is a warm-season plant that produces fruit 4 to 5 months after seeding. It does not tolerate frost, and develops leaf diseases under high humidity. Temperatures above 50° F are required for proper fruit set. Optimum performance occurs between 65° to 90° F.
Propagation and care
Specialty tomato varieties are seeded into flats 8 to 10 weeks before the planned outdoor transplant date. Plants can be set out when danger of frost has passed or they can be protected with row covers. Space the plants 2 to 4 feet apart in rows 4 to 6 feet apart. Staking plants to reduce losses from ground-contact disease is cost effective but labor intensive.
Tomatoes are best irrigated with either furrow or drip irrigation. Overhead water can be applied up to first ripening if managed properly. Drip irrigation greatly reduces weed growth.
Tomatoes have a moderate need for nitrogen fertilizer. Fruit set is delayed by high nitrogen levels, but a deficiency reduces the number of flowers. Too much moisture stress reduces yield and fruit size, but a moderate amount can intensify flavor. Large fluctuations in soil moisture contribute to blossom-end rot and fruit cracking.
Harvest and post harvest practices
Fruits should be harvested every two to three days during the peak of the season when the fruit is still firm and the final color is not quite achieved. Ripe, delicate fruits should be packed in single-layer flats, handled very carefully, and delivered within a few hours to the ultimate consumer.
Pests and disease
Although many diseases and pests can cause severe damage to the crop, tomatoes are routinely grown on a small scale without pesticides. The growing area should be rotated away from Solanaceous plants (peppers, potatoes, eggplant, tomatillas, and nightshade weeds) for one to two years. Plant disease-resistant and locally adapted varieties.
Performance of a given tomato variety varies from year to year and from one climatic region to another. Planting date, fertility, irrigation, pest control, and staking can greatly effect performance. A particular variety should not be dismissed based on one season's experience. These are some of the more promising specialty tomato varieties:
Big Rainbow: Large, yellow-orange colored fruit with red streaks in flesh; excellent flavor.
Brandywine: Large, deep red-purple colored fruit, excellent flavor.
Bragger: Very large, red, mid-season variety with excellent flavor.
Currant Tomato: Pea-sized fruit are harvested in clusters. Requires warm climate, and loses flavor if over irrigated.
Early Girl: Medium-sized, red, 5-ounce fruit; prolific, early, and excellent flavor.
Evergreen: Small, 2-inch-plus fruit; low acid, green when ripe.
Garden Peach: Small-sized, orange-yellow colored fruit with fuzzy skin.
Genovese (Costoluto): Very large, uniquely shaped, ribbed scarlet fruit.
Gold Nugget: Cherry-sized, round, golden yellow fruit, medium flavor.
Golden Boy: Large, mid-season variety; prolific, good flavor, low acid, golden orange color.
Golden Jubilee: Large, mid-season variety; sweet fruit, prolific, golden orange color.
Green Grape: Large cherry-sized, green-yellow fruit with excellent flavor.
Green Zebra: Small 1-1/2 to 2-inch fruit with light green skin turning orange, and overlaid by dark green stripes; very flavorful; susceptible to verticillium wilt; early variety.
Ida Gold: Large cherry-sized tomato with golden orange fruit; very early, prolific.
Lemon Boy: Medium-sized fruit, fair production; indeterminate plant, bright yellow fruit.
Marvel Striped: Very large, orange-yellow solid-colored fruits with red blossom end and red stripes through the flesh; sweet, prolific, early maturing.
Nepal: Medium to large red fruit; excellent flavor.
Pineapple: Large, red-yellow fruit with red streaks in flesh.
Pink Girl: Medium to large dull-pink fruit; prolific.
Purple Calabash: Small, novelty, ruffled purple-pink fruit.
Roma: Small, elongated, oval-shaped fruit; paste-type flesh, good flavor, very prolific.
Sundrop: Cherry-sized, deep orange, meaty fruit.
San Marzano: Small, red, rectangular-shaped paste tomato; excellent flavor.
Sweet 100: Cherry-sized red fruit; grows in clusters, very flavorful, very productive.
Tangerine: Large, orange, flavorful fruit.
Taxi: Small to medium-sized, bright yellow, attractive fruit; small but very prolific plant.
Tigerella: Small, early maturing, red with orange stripes, prolific.
White Beauty: Small to medium-sized green fruit turns white at maturity; soft, sweet, mild flavor; fruit ripens late.
Whopper: Medium to large red fruit with excellent flavor; good producer.
Yellow Oxheart: Very large, late maturing, heart-shaped fruit; excellent flavor, paste-type flesh.
Yellow Pear: Cherry-sized, pear-shaped, bright yellow fruit; excellent flavor.
The Cook's Garden, Box 65, Londonderry, VT 05148; (805) 824-3400
Harris Moran Seed Company, Eastern Operations (Western Operations): 1155 Harkins Rd., Salinas, CA 93901; (408) 757-3651
J.L. Hudson, Seedman, P.O. Box 1058, Redwood City, CA 94064
Johnny's Selected Seeds: 305 Foss Hill Rd., Albion, ME 04910
Nichols Garden Nursery, 1190 North Pacific Highway, Albany, OR 97321; (503) 928-9280
Redwood City Seed Co., P.O. Box 361, Redwood City, CA 94604; (415) 325-7333
Seeds Blum, Idaho City Stage, Boise, ID 83706
Shepherd's Garden Seeds, 7389 West Zayante Rd., Felton, CA 95018
Territorial Seed Co.: P.O. Box 27, Lorane, OR 97451