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Selecting Tomatoes for the Home Garden

This publication will help home gardeners choose from a variety of tomato cultivars to find what they want.

• Tomato Classification, Growth Habits and Pollination

Figure 1. There is no direct link between fruit acidity and color.

Tomatoes, Solanum lycopersicum (formerly Lycopersicon esculentum), are available in a wide range of fruit colors, sizes, shapes, and maturities. Ripe tomatoes may be red, orange, pink, yellow, white, or even green with shapes varying from globe or round to slightly flattened, pear-like, or cherry-sized.

Consumers sometimes complain that tomatoes purchased in grocery stores lack flavor or have tough skin. Although nurseries and garden centers can provide only a limited number of different tomato cultivars, home gardeners willing to grow their own tomato transplants can choose from among hundreds of tomato cultivars, selecting those with the color, texture, size, and taste they prefer. Although rumored, there is no direct link between fruit acidity and color. Yellow tomatoes, which many home gardeners believe have lower acidity, actually have a normal acidity level but also a higher sugar content, which changes the flavor (Figure 1).

When discussing tomatoes, the term cultivar, a contraction of the terms “cultivated variety,” refers to any group of plants with distinct characteristics that are preserved through controlled propagation, such as hybridization or cuttings. In contrast, the term variety refers to a subdivision of a species that evolved without human intervention, often within a distinct geographical area, and will breed true when isolated from other tomatoes. Often the term variety is used incorrectly to refer to any distinct tomato type. Almost all tomatoes should be referred to as cultivars, since even heirloom tomatoes were developed through years of human selection for plants with the best characteristics.

Certain tomato cultivars have been developed for special uses such as stuffing (Pink Stuffer, Yellow Stuffer, Striped Cavern) or longer storage (Burpee’s Long Keeper).

Very dwarf cultivars adapted for growth in pots or other containers also are available. Most of these “patio” cultivars have cherry-sized fruit, like Pixie II and Orange Pixie, although a few, like Bush Steak, Patio, and Patio Princess, produce regular-sized fruit.

Tomato Classification, Growth Habits and Pollination

Common tomato classifications include:

• Standard tomatoes usually are smooth and round, and are larger in size than salad tomatoes but smaller than beefsteak types. Also called slicing or main season tomatoes, standard tomatoes are the most common tomato type. This group includes well known cultivars like Better Boy, Celebrity, Early Girl, and Rutgers.
  
  
• Beefsteak tomatoes have the largest fruits, sometimes weighing up to a pound or more. They have dense flesh and numerous small seed cavities, and often mature late in the growing season. The term beefsteak refers to a group of tomatoes with similar fruit characteristics, although there also is a cultivar named Beefsteak. Usually these fruits are globe shaped, but some cultivars have an irregular shape. Common cultivars include Beefmaster, Big Beef, and heirlooms like Brandywine and Cherokee Purple.
  
  
• Salad tomatoes, including currant, cherry, grape, and pear types, produce small, bite-sized fruits. These small-fruited varieties develop large, sprawling plants that grow and produce fruits even under hot, dry conditions. Common cultivars include Sun Gold, Super Sweet 100, Large Red Cherry, Red Grape, and Yellow Pear. Currant tomato, S. pimpinellifolium, actually is a distinct species, however, it will readily cross with other tomatoes, so keep plants isolated if you plan to save seed.
  
  
• Paste tomatoes have thick, somewhat dry flesh, with small seed cavities and less locular gel, making them good candidates for processing into sauces and tomato paste. Usually paste tomatoes have an elongated shape. Common cultivars include Roma, San Marzano, and Viva Italia.

Tomatillos, and ground cherries are sometimes confused with tomatoes. These plants belong to the genus Physalis rather than the tomato genus Solanum.

Home gardeners should carefully consider the amount of space available in their garden when deciding which tomato cultivars to grow. Planting a combination of cultivars with different growth types will result in a long season of fresh tomatoes. The two most common growth forms for tomato plants are determinate and indeterminate.

• Determinate plants, sometimes called bush tomatoes, grow only to a set height then stop. Determinate tomato plants range from less than 2 feet to about 3 feet tall. Plants develop short branches, each ending in a flower cluster, and then set fruit. Growth stops at a finite height and terminal flower clusters form at the top. Fruits ripen and are harvested in less than six weeks. Production is limited by the short height of the plant, as growth and branching is restricted. For this reason, determinate tomatoes are ideal for canning or freezing since the majority of the produce can be harvested and processed within a short time frame. Some determinate cultivars provide high early yields before other tomato types begin producing.
  
  
• Indeterminate tomatoes, often called vining tomatoes, grow continuously until killed by frost. Each plant has many branches and suckers, and plants can get quite large. These plants flower and set fruit continuously until the plant dies, resulting in a staggered harvest throughout the growing season.
  
  
• Semi-determinate plants are intermediate in size between determinate and indeterminate types, producing fewer suckers than indeterminate plants, and usually reach a height of 3 to 5 feet.
  
  
• Dwarf indeterminate is a new tomato classification, producing very short, bushy plants similar to determinate types, but which keep flowering and producing fruit continuously like indeterminate types. Cultivars include Husky Red Cherry and Husky Gold.

Many tomato cultivars on the market today are hybrids. Tomato plants are self-pollinating, however, hybrid seed can be produced through a laborious process involving the hand crossing of two different parent plants. The resulting hybrid seed or progeny display specific characteristics inherited from the parent plants. However, when seed is harvested from the hybrid plants and grown out the following year, it will not grow true to type because of genetic recombination. Therefore, gardeners should not save seed from hybrid plants, with the expectation that the resulting plants will be similar to the hybrid parent.

Increasingly popular today are heirloom tomatoes. The definition of an heirloom tomato varies, but usually refers to open pollinated plants that were in cultivation before 1940, when the first hybrid cultivars became widely available. Often heirlooms have been passed down within families or communities for many years, with seed selected from the best plants each year. All heirlooms are open pollinated. Open pollinated plants, when isolated from other tomatoes, will grow true to type each year and their seed can be saved with the expectation of the same plant and fruit quality each year.

Most new tomato cultivars are resistant to or tolerant of certain diseases. This usually is indicated by a letter following the name, such as “N” for nematodes, “F” for Fusarium race 1, “FF” for Fusarium race 1 and 2, “FFF” for Fusarium race 1, 2 and 3, “T” for tobacco mosaic virus, and “V” for Verticillium wilt. Cucumber mosaic virus (CMV) and tomato spotted wilt virus (TSWV), Alternaria stem canker (ASC), gray leaf spot (St), and Septoria leaf spot (L) indicate additional disease resistance. Realize that not all tomato cultivars have the same level of resistance, and even resistant plants can become infected if disease pressure is very high. Some plants are labeled as tolerant to certain diseases indicating that they will produce fruit of acceptable quality even with moderate to high levels of disease infection.

Although open-pollinated heirloom cultivars are now popular, many have little genetic resistance to common diseases. These older cultivars should be planted in ground that has not had any Solanaceous crops (tomato, pepper, eggplant, or potato) for at least three years and in a place with good air circulation to reduce the opportunity for fungal infection.

All-American Selections (AAS) are cultivars tested at trial gardens across the United States. Cultivars must be unique, widely adapted, and provide a quality product to receive this honored award.

Early season tomatoes require 65 or fewer days from transplanting to harvest; main season tomatoes 70 to 79 days; and late season tomatoes more than 80 days.

This publication has been peer reviewed.