Tomatoes. KidsGardening.org is a resource of the National Gardening Association

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1 Tomatoes INTRODUCTION The most popular vegetable of home gardeners, tomato plants are also common residents in school gardens. With fresh tomatoes on sandwiches and burgers, and processed tomatoes in pizza, salsa, and catsup, it s hard to make it through a day without eating a tomato or tomato-based product. Fruits come in many different sizes (cherry to beefsteak), shapes (oblong, pear-shaped, and round), and colors (red, yellow, green, and purple). It s rare to see tomatoes of unusual shape or color in the grocery store, but there are hundreds of interesting varieties that you can grow from seed. The horticulture industry invests millions of dollars annually selecting and developing new tomato varieties to tempt both commercial growers and backyard gardeners. ORIGIN AND BRIEF HISTORY Scientists believe tomatoes originated in the Andes Mountains of Peru and were brought to Central America and Mexico by emigrating Indians. The first written record of the tomato dates to the 1550 s when European explorers returned home from Mexico with tomato plants. The Italians documented eating the fruit, but gardeners in England, Spain, and France dared grow it only for its ornamental value because of its close resemblance to deadly nightshade (Atropus belladonna). It s true that the leaves and stems contain toxins that are harmful if consumed in large quantity, but eventually Europeans discovered that the fruit itself was safe and tasty. By the mid-1700s it was firmly established as a popular food crop in Europe. Ironically, tomatoes were introduced to the United States via European colonists in the late 1700s rather than by movement up the continent from Mexico.

2 PLANTING PLANNING Tomatoes are classified by their growth habit and considered indeterminate, determinate or semi-determinate: Indeterminate plants continue to grow taller and set fruits throughout the season, stopping only when frost finishes them off. These large vines need sturdy supports that will accommodate their continued growth until frost. Determinate vines grow to a particular height, usually under 4 feet; then set their fruits within a relatively short time period. Determinate varieties also generally ripen the earliest, making them a good choice for gardeners in short-season parts of the country. Semi-determinate varieties fall between these two types. Like determinate tomatoes, they grow only to a certain height, often a little taller than determinate varieties. But like indeterminate varieties, they continue to produce new fruits all season long. Tomatoes stop setting fruit when night temperatures are higher than 70 F, so gardeners in the Deep South grow them as a spring and fall crop. Gardeners elsewhere in the United States grow them as a summer crop. Tomatoes self-pollinate, so a single plant will produce fruit (although planting more than one provides insurance against loss due to disease or insect problems). PREPARATION Tomato plants take 4-5 months from germination to first harvest, so no matter where you re gardening, you need to give your plants a head start by setting out transplants in the garden. Start tomatoes from seeds indoors or purchase seedlings from garden centers. Plant them after the last spring frost date in your region, but make sure to have something available, such as bed sheets or water-filled tepees, to protect plants from late frosts. In northern climates, plant in raised beds and put down black or red plastic mulch to warm up the soil a couple of weeks prior to planting. PLANTING To produce fruits, plants need 6 to 8 hours of full sun, ample water, and fertile, well-draining soil. Spacing of plants will depend on the type of support you plan to use. Staked or trellised plants can be set as close as 2-3 feet apart; set caged plants about 4 feet apart. When you set your transplants in the garden, plant them deep. Unlike most other vegetable plants, tomatoes will form roots along the buried stem. You can bury the stem under soil up to the first set of leaves, which will add to stability and increase root area. Tomato plants are considered heavy feeders and need adequate fertilization for healthy growth. When planting, dig a hole 3 to 4 inches deeper than necessary then add a thin band of organic fertilizer or compost to the bottom. Cover the fertilizer with 2 to 3 inches of soil and then plant. Avoid over fertilizing, however, since too much fertilizer can lead to excessive leaf growth and few fruits. Provide some type of support for your tomato plants. Tomatoes that are allowed to sprawl on the ground are more prone to disease problems as disease-causing spores will easily splash up from the soil on to foliage and fruit and horizontal growth may lead to shading which will decrease productivity. Be sure to have supports in place before planting to avoid damaging the root system later on.

3 CARE Pruning excessive foliage can be helpful at times. It will reduce the overall yield of your tomato plant, but pruned plants tend to produce larger fruits that ripen a little earlier than those on unpruned vines. Cracking occurs when a tomato suddenly enlarges too quickly as it ripens. To control this problem, try to keep soil moisture consistent by watering regularly, and make sure the soil around the plants is well mulched. PEST AND PROBLEMS Rotating the location of your tomato plants and their relatives (peppers, eggplants, potatoes) can help to short-circuit some insect and disease problems. Try for a three-year rotation, if possible. Choose disease resistant varieties, indicated by letters after the variety name. Look for ones with resistance to verticillium (V) and fusarium (F) wilts, tomato mosaic virus (TMV), nematodes (N), late blight (LB), and other diseases. Keep plants watered consistently throughout the growing season to reduce problems with blossom end rot, a physiological disorder related to fluctuations in soil moisture. Clean up and dispose of all plant debris in the tomato patch at the end of the season. This will reduce the number of overwintering insects and disease spores that will be around to cause problems the following season. FUN FACT: In 1983, the tomato made an appearance in the United States Supreme Court. The Tariff Act of 1883 placed a tax on imported vegetables, including tomatoes, so a knowledgeable importer challenged that the tomato is botanically a fruit and not subject to these taxes. However, the Supreme Court ruled that even though the tomato is botanically a fruit, in practical terms it is consumed as part of meal like other vegetables and that fruits are usually consumed individually or as a dessert. Therefore by ruling of the Supreme Court the tomato is a vegetable. So if you re asked if a tomato is a fruit or a vegetable, the answer is, Both! HARVESTING Fruits continue to ripen after picked, so you can harvest them before they are fully ripe to prevent birds and rodents from munching on them. Tomatoes ripen from the inside out, when the outer skin is firm and red, you know you ve got a ripe one. If faced with an overwhelming harvest, remember tomatoes can be preserved through canning and freezing for consumption later in the year.

4 LESSON IDEAS MATO MATH Because tomatoes come in so many different shapes and sizes, they are ideal for exploring a variety of math concepts. Here are a few ideas: Counting: Ask students to estimate the number of seeds in different types of tomatoes then cut them open and see how their predictions measure up. Determine if there is a relationship between tomato size and number of seeds. Repeat to determine if the accuracy of their estimations improves. Measurement and Data: Track the tomato harvest from your garden. Weigh and measure the circumference of different types of tomatoes. Graph and compare your results and discuss your findings. Statistics and Probability: Obtain a pack of tomato seeds that provides a germination rate (Willhite Seeds is one source that offers this feature: Plant your seeds and discover the germination rate under your growing conditions; then compare to that listed on the packet. PRESERVING THE HARVEST Especially if you grow determinate tomato plants, you may find you are harvesting more fruit than you can consume at one time. You can donate excess tomatoes to teachers and families at your school or to local food banks, or alternatively, you can employ a preservation technique to save some of the harvest for a later date. Introduce students to common preservation techniques including canning, freezing and drying. If possible, prepare tomatoes using each technique. Discuss the benefits and history of food preservation. TOMATO SAMPLING EVENT Prepare the Bring Home the Fun Recipe with your class. By demonstrating preparation methods and sampling the final product in the classroom, students will be ready to share the recipe with their family. FRUIT VS VEGETABLE By decree of the United States Supreme Court in 1893, even though botanically it is a fruit (a seed bearing structure), the tomato is considered a vegetable because it is typically consumed as part of a meal. As a class, make a list of all the common vegetables we eat that are actually fruits (e.g.., cucumbers, squash, peppers). FUN FACT: Besides having a delicious flavor, tomatoes provide important nutrients including vitamin C, folate, potassium, magnesium, and calcium. They received another public-relations boost when they were identified as an excellent source of the antioxidant phytonutrient lycopene. Researchers have discovered links between consuming tomatoes and tomato products and the prevention of many types of cancers.

5 BRING HOME THE FUN WITH Tomatoes The iconic tomato may be round and red, but there is a lot more variety than that out in the world of tomatoes. With fruits available in a wide arrange of sizes, in shapes varying from globe to pear-shaped, in colors ranging from classic red-orange to yellow, pink, and orange, borne on vines that reach from a foot and a half tall to six feet high or more, there s a tomato to fit every home garden. To grow healthy tomato plants at home, you will need a location that provides 6 to 8 hours of full sun, ample water, and fertile, well-draining soil. Tomatoes can be grown directly it the ground, in raised beds or in containers (tomatoes need plenty of room for their roots, so containers and raised beds need to be 18 to 24 deep). To properly prepare your garden harvest, wash tomatoes well in warm water and a produce wash, according to the manufacturer s direction. Remove the stem and the calyx, the green, leaflike structures at the base of the stem, from the tomato using a paring knife or shark (a special tool with serrated scoop to remove the calyx). Tomatoes are known to most students in processed forms like ketchup and pizza, but many may not have cooked with or eaten a raw tomato. The recipe below is for a mild salsa that will introduce your students to the full flavor of fresh tomatoes without a lot of heat that may discourage some. Mild Tomato Salsa Tip: To get the students involved in prep, give them cutting boards and plastic kid-safe knives and have them dice tomatoes and avocados. Students can also help measure ingredients and squeeze lime juice. Serving Size: 2 Tbsp Salsa, Makes 32 Servings (plus corn chips) 1 2 lbs fresh tomatoes, cleaned and trimmed as above 1 small red onion 2 ripe avocados 1 fresh lime 1 tsp salt 1 bag baked corn chips, preferably low sodium 1. Begin by cutting tomatoes in halves and scooping out the seeds and gel with a large spoon. 2. Lay tomato halves flat and dice into ¼ inch pieces. 3. Peel and dice red onion to the same size, and the same with the avocados. 4. Stir all diced ingredients together, then squeeze fresh lime juice into the salsa and add salt. 5. Stir a few times more and serve in portion cups with corn chips.