Tomatoes are a favorite garden vegetable of many. It is fairly easy to grow in a garden, and smaller varieties can be grown in containers by those with limited space. Tomatoes are low in calories but rich in nutrients, providing significant amounts of vitamins C and A, along with iron. However, a Purdue expert said it was not always so popular.
The tomato is native to South America and introduced by early explorers into Europe where it became known as the “Apple of Love” in France and Italy. “It was not generally cultivated in the United States until 1835 because, until then, it was widely believed to be poisonous,” said Rosie Lerner, retired consumer horticulture specialist at Purdue University in her publication entitled, “Tomatoes.”
Tomatoes come in various shapes, sizes, and colors, with new cultivars offering improved disease resistance and specific uses, such as paste tomatoes for sauces. “While red tomatoes are the most common, yellow, orange, and pink tomatoes are sometimes grown,” said Lerner. “Sizes range from bite-size cherry types to the giant beefsteak tomatoes.”
Most tomatoes can be used fresh for eating and cooking, but paste or Roma-type tomatoes are best suited for cooking down to sauces or used for ketchup.
Selection of a favorite tomato variety is a life-long pursuit for some avid gardeners. There are new varieties each year to choose from and experiment with.
“Tomatoes will grow in many different soil types, but a deep, loamy, well-drained soil is ideal,” said Lerner. “Tomatoes grow best in a slightly acid soil with a pH of 6.2-6.8.”
Tomatoes are typically transplanted into the garden, rather than direct-seeded. Choose short, stocky plants with a thick stem and dark green color. Transplanting should always take place after danger of frost is past. Tomatoes should be in full sun, or a minimum of 6 hours of direct sunlight per day. Do not plant near walnut trees.
Tomatoes are classified as determinate (bush-type), indeterminate, or dwarf. Determinate tomatoes grow to a certain height, then flower and fruit at a more “determinate” time than spread out all season long. Smaller in stature, determinate and dwarf tomatoes are better suited for containers, while indeterminate tomatoes are normally grown in a garden setting. Indeterminate tomatoes produce fruit continuously throughout the season.
Tomatoes can benefit from staking or caging for better air circulation and disease prevention. “Tomatoes need 1 to 1-1/2 inches of water per week to maintain plant health and good quality fruit,” said Lerner. “Applying a mulch will help conserve soil moisture by preventing evaporation and will help prevent extremes in the moisture supply.”
Tomatoes can be picked “vine-ripe” at the peak of freshness and maturity. They can also be picked a little early and allowed to fully ripen off the plant. This may be particularly helpful as the danger of frost nears, or to better avoid sunscald and skin cracking during the growing season.
When canning, some have feared that low-acid tomatoes could cause botulism poisoning. “The acidity of a tomato does vary depending on location in the garden and degree of ripeness,” said Lerner. “However, the low-acid tomatoes are just as acidic as other tomatoes.” She said that low-acid tomatoes just have a higher sugar content, which makes them taste less acidic.
For more information about growing tomatoes, access Lerner’s publication at www.edustore.purdue.edu. Additionally, find a wealth of information about using tomatoes and other vegetables at Purdue Extension’s FoodLink, https://extension.purdue.edu/foodlink/.