The thrill of growing tomatoes. It’s almost an indescribable pleasure. There are tips, tricks and lore. Ongoing debate ensues. Pizza or pasta? Fruit or vegetable? Love apple or…? Determinate or indeterminate? Heirloom or hybrid? Guinness lists the largest tomato ever grown as 7 lbs, 12 oz. Here, we’ll simply outline a few of the basics about kinds of tomatoes to help you navigate which ones you wish to try beat the record books…
Determinate and Indeterminate: What’s the Dif?
DETERMINATE varieties of tomatoes are also called “BUSH” tomatoes. They are varieties that are bred to grow to a compact height (average 4 feet)
• Determinate tomatoes stop growing when fruit sets on the “terminal” or top bud of the plant. They ripen all of their crop at or near the same time (usually over a 2 week period) and then start to die
• These tomatoes require CAGING and/or STAKING for support.
• They SHOULD NOT be pruned or “suckered” as it severely reduces the crop production.
• Determinate tomatoes produce relatively well in a good sized container (at least 5 gallons)
• VARIETIES INCLUDE: Roma, Tumbler, Manitoba, Patio, San Marzano
INDETERMINATE varieties of tomatoes are sometimes called “VINING” tomatoes.
• Indeterminate tomatoes will grow and produce fruit until killed by frost
• These tomatoes can reach tall heights of up to 10 feet (6 feet average).
• Indeterminate tomatoes will bloom, set fruit and ripen fruit all at the same time
• Throughout the growing season these plants require SUBSTANTIAL CAGING and/or STAKING for support.
• Pruning of suckers (small leaves growing between plant branches) is recommended to encourage fruit set.
• VARIETIES INCLUDE: Early Girl, most cherry types, most heirloom varieties
Heirlooms or Hybrids?
An heirloom is generally considered to be a variety that has been passed down, through several generations of a family because of its valued characteristics. For our purposes, heirloom tomatoes are open-pollinated varieties introduced before 1940, or tomato varieties more than 50 years in circulation. Open-pollinated plants are simply varieties that are capable of producing seeds that will produce seedlings just like the parent plant (not all plants do this). Note: All heirloom varieties are open-pollinated but not all open-pollinated varieties are heirloom varieties.
With large changes in food production, we have lost many varieties of heirloom tomatoes in the last 40 years. The multitude of heirlooms that existed for hundreds of years are being replaced by fewer hybrid tomatoes. In the process we have also lost varieties of foods typically grown by family gardeners and small farms, and we have decreased genetic diversity. Every heirloom variety is genetically unique and this uniqueness includes an evolved resistance to pests and diseases and an adaptation to specific growing conditions and climates. We welcome you to our smorgasbord.
Plant breeders cross breed compatible types of plants in an effort to create a plant with the best features of both parents. These are called hybrids and many of our modern plants are the results of these crosses. While plants can cross-pollinate in nature (open pollination) and hybrids repeatedly selected and grown may eventually stabilize, many hybrid seeds are relatively new crosses and seed from these hybrids will not produce plants with identical qualities.
For example, each year new hybrid tomato varieties are offered. You may see them labeled as hybrids or F1, first filial generation (first-generation hybrid), or F2. These may eventually stabilize, but for the moment a tomato like the popular ‘Early Girl’ does not produce seeds that reliably have the features you expect in an ‘Early Girl’ tomato.
Anyone can select and eventually stabilize their own seed or even hybridize new plants, but plant and seed companies have recently begun patenting their crosses so that only have the right to reproduce the hybrids they’ve developed.
Genetically Modified Plants
Hybrids should not be confused with genetically modified organisms or (GMOs) which can be any plant, animal or microorganism which have been genetically altered using molecular genetics techniques such as gene cloning and protein engineering. Plants like corn that has the pesticide Bt engineered into its genetic makeup to make it resistant to certain pests are GMO crops. Bt is a natural pesticide, but it would never naturally find its way into corn seed. There are new efforts to mark food sources, such as tomatoes, with non-GMO labels so customers know that this particular plant and variety has not been genetically modified. It should be noted, that there are many plants without these labels that are also non-GMO, they simply just don’t have the label identifying it as such.