A Complete Guide to Growing Tomatoes
Tomatoes (Solanum lycopersicum) are among the most popular vegetables for home gardeners worldwide. They are versatile in the kitchen, highly productive, and rewarding to grow. Whether you have a large garden, a small greenhouse, or just a sunny balcony, you can grow tomatoes successfully with the right knowledge and care.
This guide covers everything you need to know about growing tomatoes, from understanding different varieties to sowing, transplanting, care, and harvesting.
Understanding Tomato Growth Types
Before choosing which tomatoes to grow, it is essential to understand the two main growth types. This determines how you will support and care for your plants throughout the season.
Indeterminate tomatoes (also called vining or cordon tomatoes) continue to grow throughout the season. They produce new leaves, flowers, and fruit continuously until frost kills them or the season ends. These plants can grow very tall, sometimes exceeding 2 meters in height. They require strong support such as stakes, cages, or trellis systems.
On indeterminate plants, flower clusters form every third leaf along the main stem and side shoots. To maximize fruit production and plant health, gardeners remove the side shoots (also called suckers) that develop in the leaf axils. This practice directs the plant’s energy into fruit production rather than excessive foliage growth.
Indeterminate varieties produce fruit over an extended period. You can harvest ripe tomatoes continuously for many weeks. This makes them ideal if you want fresh tomatoes throughout the summer rather than a single large harvest.
Determinate tomatoes (also called bush tomatoes) grow to a predetermined height and then stop. They typically reach 60 to 120 centimeters tall. The plant sets its fruit over a shorter period, and most tomatoes ripen within a few weeks of each other.
Do not remove suckers from determinate tomatoes. These plants are bred to grow as compact bushes, and removing side shoots reduces the harvest. Determinate varieties generally require less support than indeterminate types, though some support is still helpful to keep fruit off the ground.
Determinate varieties are useful when you want a large harvest at once, such as for canning or making sauce. They are also well-suited to container growing and small spaces.
Main Types of Tomatoes by Fruit Characteristics
Beyond growth habit, tomatoes are classified by fruit size, shape, and use.
Standard slicing tomatoes are the classic round, medium to large tomatoes used fresh in sandwiches, salads, and cooking. They typically weigh 100 to 250 grams each. Many popular varieties fall into this category. These tomatoes balance sweetness and acidity and work well for multiple purposes.
Beefsteak tomatoes are large, meaty tomatoes that can weigh 250 grams to over 500 grams each. They have thick flesh with relatively few seeds. The large size makes them excellent for slicing onto sandwiches or burgers. Beefsteak varieties often have irregular, ribbed shapes. They require longer growing seasons and more care than smaller varieties. The large fruit needs consistent watering to prevent cracking, and the heavy weight requires strong plant support.
Plum tomatoes (also called paste tomatoes or Roma-type tomatoes) have an elongated, oval shape with thick walls, dense flesh, and fewer seeds than round varieties. These characteristics make them ideal for cooking, canning, and making sauces. The lower water content means the sauce thickens quickly with less cooking time. Classic examples include Roma and San Marzano varieties. San Marzano tomatoes are particularly prized for authentic Italian pasta sauce due to their sweet flavor and low acidity.
Cherry tomatoes are small, bite-sized tomatoes, typically 1 to 3 centimeters in diameter. They are usually round, though some varieties are elongated (often called grape tomatoes). Cherry tomatoes tend to be very sweet and are popular for snacking, salads, and garnishes. They are often prolific producers and many varieties are determinate, making them excellent for containers and small gardens.
Grape tomatoes are similar to cherry tomatoes but have an elongated shape like a grape. They often have thicker skin and a firmer texture than cherry tomatoes, making them last longer after harvest.
Cocktail tomatoes are intermediate in size between cherry and standard tomatoes, typically 3 to 5 centimeters in diameter. They are often sold in clusters and combine the sweetness of cherry tomatoes with more substance.
Tomato Colors and Varieties
Tomatoes come in many colors beyond the classic red. Each color indicates different phytonutrient profiles and flavors.
Red tomatoes contain high levels of lycopene, a powerful antioxidant. Lycopene gives tomatoes their red color and has been studied for its potential health benefits.
Yellow and orange tomatoes are typically milder and sweeter than red varieties with lower acidity. They contain beta-carotene and other carotenoids.
Pink tomatoes are often prized for their balanced, sweet flavor with low acidity.
Green tomatoes (when ripe, not unripe red varieties) such as Green Zebra have a tangy, sometimes citrus-like flavor.
Purple and black tomatoes contain anthocyanins in addition to lycopene, giving them their dark color. They often have complex, rich flavors.
White or cream tomatoes are very mild with low acidity.
Climate and Growing Conditions
Tomatoes are warm-season plants that originated in the tropical regions of Central and South America. Understanding their climate requirements is essential for successful cultivation.
Temperature requirements. Tomatoes need warm conditions to thrive. Seeds germinate best at soil temperatures between 20 and 30 degrees Celsius. Germination slows significantly below 15 degrees and stops below 10 degrees. Mature plants grow best when daytime temperatures are between 20 and 30 degrees Celsius with nighttime temperatures between 15 and 20 degrees.
Temperatures above 35 degrees can cause problems. Pollen becomes less viable, leading to poor fruit set. Extreme heat can also cause sunscald on fruit and leaf damage. Temperatures below 10 degrees slow growth significantly, and frost kills tomato plants.
Light requirements. Tomatoes need full sun, meaning at least 6 to 8 hours of direct sunlight daily. More light generally means more fruit production. In very hot climates, some afternoon shade may be beneficial to prevent heat stress, but in temperate climates, maximum sun exposure produces the best results.
When starting seeds indoors, provide strong light immediately after germination. Insufficient light causes seedlings to become tall, weak, and spindly. Use a sunny windowsill or supplemental grow lights.
Soil requirements. Tomatoes prefer well-drained, fertile soil rich in organic matter. The ideal pH range is 6.0 to 6.8, slightly acidic to neutral. Good drainage is essential because waterlogged soil promotes root diseases.
Before planting, prepare the soil by working in compost or well-rotted manure. A general guideline is approximately 2 to 3 kilograms of compost per square meter. This improves soil structure, drainage, and nutrient content.
Starting Tomatoes from Seed
Starting tomatoes from seed gives you access to many more varieties than buying transplants. It also allows you to control growing conditions from the beginning.
Timing. Start seeds indoors 6 to 8 weeks before your planned transplanting date. In most temperate climates, this means sowing in late winter or early spring. Calculate backward from the date when outdoor temperatures are consistently warm enough for transplanting.
Sowing process. Fill seed trays or small pots with seed-starting mix. Moisten the mix before sowing. Plant seeds approximately 6 millimeters deep, roughly 2 to 3 times the seed diameter. A general rule is to plant seeds at a depth equal to 2 to 3 times their own thickness. Press the soil gently to ensure good seed-to-soil contact.
Germination conditions. Tomato seeds germinate best at temperatures between 20 and 30 degrees Celsius. At optimal temperatures, germination takes 5 to 10 days. Lower temperatures significantly slow germination.
Keep the soil consistently moist but not waterlogged during germination. Covering containers with plastic wrap or clear lids helps maintain humidity. Make small holes in the covering to allow some air circulation and prevent mold.
Once seedlings emerge, remove the covering and provide strong light immediately. Continue to keep soil moist but allow the surface to dry slightly between waterings.
Caring for seedlings. When seedlings develop their first true leaves (the second set of leaves, after the initial seed leaves or cotyledons), they can be transplanted into individual containers if they were sown in shared trays. This process is called pricking out.
Begin feeding with diluted liquid fertilizer when true leaves appear. Use a balanced fertilizer at half the recommended strength. Feed every 1 to 2 weeks.
Before transplanting outdoors, seedlings need hardening off. This process gradually acclimates plants to outdoor conditions over 7 to 14 days. Start by placing plants outdoors in a sheltered location for a few hours daily, gradually increasing exposure to sun, wind, and temperature fluctuations.
Transplanting Tomatoes
Transplant tomatoes outdoors when all risk of frost has passed and soil temperatures have warmed to at least 15 degrees Celsius. In most temperate climates, this is late spring to early summer.
Site selection. Choose the sunniest spot available. Ensure good air circulation to reduce disease problems. Avoid planting where tomatoes, peppers, eggplants, or potatoes grew in the previous 2 to 3 years, as these related plants share common diseases.
Planting depth. Tomatoes have the ability to form roots along their stems. Take advantage of this by planting seedlings deep. Remove the lower leaves and bury the stem up to just below the remaining leaves. This produces a stronger root system and more stable plants.
Spacing. Space indeterminate varieties 45 to 60 centimeters apart in rows 60 to 90 centimeters apart. Determinate varieties can be spaced slightly closer, 30 to 45 centimeters apart. Adequate spacing allows air circulation, which reduces disease, and provides room for the plants to grow and for you to access them for care and harvesting.
Planting procedure. Dig a hole larger than the root ball. Mix compost or well-rotted manure into the planting hole. Remove the plant from its container carefully, keeping the root ball intact. Place the plant in the hole, fill with soil, and firm gently around the base. Water thoroughly after planting.
Supporting Tomato Plants
All tomatoes benefit from support, though the type depends on the growth habit.
Stakes. A traditional method for indeterminate varieties. Drive a sturdy stake at least 150 to 180 centimeters tall into the ground 30 to 60 centimeters deep, positioned near the plant at planting time. As the plant grows, tie the main stem to the stake using soft ties or strips of cloth. Tie loosely to avoid damaging the stem.
Cages. Wire tomato cages encircle the plant and support branches as they grow outward. Commercial cages are often too small and flimsy for vigorous indeterminate varieties. Homemade cages using concrete reinforcing wire (with openings large enough to reach through for harvesting) work better. Cages work well for both determinate and indeterminate varieties.
Trellises. String or wire trellises allow vertical growing. Plants are trained up strings suspended from an overhead support. This method is common in greenhouses and commercial production but works well in home gardens too.
Watering Tomatoes
Consistent watering is one of the most important factors for healthy tomato plants and quality fruit.
Frequency and amount. Tomatoes need regular, deep watering rather than frequent shallow watering. Aim to keep soil consistently moist but not waterlogged. In hot weather, this may mean watering daily or even twice daily. In cooler weather or during rainy periods, watering may be needed only every few days.
Water deeply to encourage deep root growth. Shallow watering encourages shallow roots, making plants more susceptible to drought stress.
Timing. Water early in the morning when possible. This allows foliage to dry during the day, reducing disease problems. Evening watering is the second choice. Avoid watering during the hottest part of the day when much water is lost to evaporation.
Method. Water at the base of the plant, not on the leaves. Wet foliage promotes fungal diseases such as early blight and late blight. Drip irrigation or soaker hoses are ideal because they deliver water directly to the soil without wetting foliage.
Mulching. Apply a layer of organic mulch such as straw, dried grass, or wood chips around plants after they are established. Mulch conserves soil moisture, moderates soil temperature, suppresses weeds, and prevents soil from splashing onto lower leaves, which can spread disease. Keep mulch a few centimeters away from the stem to prevent rot.
Consistency. Irregular watering, alternating between drought and flooding, causes problems including blossom end rot (dark, sunken areas at the bottom of fruit) and fruit cracking. Consistent moisture is key.
Fertilizing Tomatoes
Tomatoes are heavy feeders that benefit from regular fertilization throughout the growing season.
At planting. Incorporate compost or well-rotted manure into the soil before planting. This provides a foundation of nutrients and improves soil structure.
During growth. Once plants are established and beginning to flower, begin regular feeding every 7 to 14 days. Use a balanced fertilizer or one formulated specifically for tomatoes. Tomato fertilizers typically have higher potassium (K) relative to nitrogen (N), which promotes fruit development over excessive foliage growth.
Organic options. For organic growing, use compost tea, fish emulsion, seaweed extract, or well-aged manure. These provide nutrients along with beneficial microorganisms.
Signs of nutrient problems. Yellow lower leaves often indicate nitrogen deficiency. Purple coloration on leaves may indicate phosphorus deficiency. Poor fruit set despite healthy plants may indicate potassium deficiency. Blossom end rot is associated with calcium deficiency, though it is usually caused by inconsistent watering rather than lack of calcium in the soil.
Pruning and Training Tomatoes
Pruning practices differ between determinate and indeterminate varieties.
Indeterminate varieties. Regular pruning improves air circulation, reduces disease, directs energy into fruit production, and makes plants easier to manage. The main pruning task is removing suckers, the shoots that develop in the leaf axils (the angle between the main stem and a branch).
Remove suckers when they are small, preferably less than 5 centimeters long. Pinch them out with your fingers or cut with clean pruners. Removing larger suckers leaves larger wounds that are more susceptible to infection.
Some gardeners remove all suckers for a single-stem plant. Others allow one or two suckers to develop into secondary stems for increased production. Experiment to find what works best in your conditions.
Remove lower leaves as the plant grows, especially any that touch the ground or show signs of disease. This improves air circulation and reduces disease transmission from soil splash.
Late in the season (approximately 4 to 6 weeks before the expected first frost), pinch out the growing tip of indeterminate plants. This stops new growth and directs the plant’s remaining energy into ripening existing fruit.
Determinate varieties. Do not remove suckers from determinate tomatoes. These plants are bred to grow as bushes, and removing side shoots significantly reduces the harvest. Minimal pruning is needed. You may remove lower leaves that touch the ground or show disease.
Common Tomato Problems
Understanding common problems helps you prevent or address them quickly.
Blossom end rot. Dark, sunken, leathery patches develop at the bottom (blossom end) of fruit. This is caused by calcium deficiency in the developing fruit, usually due to inconsistent watering rather than lack of calcium in the soil. Maintain consistent soil moisture to prevent this problem.
Cracking and splitting. Fruit develops cracks, either concentric (circular) around the stem or radial (lengthwise). This occurs when rapid water uptake causes the fruit to expand faster than the skin can stretch, typically after heavy rain or watering following a dry period. Consistent watering and mulching help prevent cracking.
Blossom drop. Flowers fall off without setting fruit. Common causes include temperatures too high (above 30 degrees) or too low (below 13 degrees), insufficient pollination, or nutrient imbalances.
Catfacing. Misshapen fruit with scars and cavities, usually at the blossom end. Caused by cold temperatures during flowering. Most common on beefsteak and large-fruited varieties.
Sunscald. Light-colored, papery patches develop on fruit exposed to intense sun. More common when plants lose leaves to disease or when fruit is not shaded by foliage. Maintain healthy foliage to shade fruit.
Early blight. Fungal disease causing dark spots with concentric rings on lower leaves, gradually moving upward. Remove affected leaves, improve air circulation, avoid wetting foliage, and apply mulch to prevent soil splash.
Late blight. Serious fungal disease causing large, dark, water-soaked areas on leaves and fruit. Spreads rapidly in cool, wet conditions. Remove and destroy affected plants immediately. Do not compost infected material.
Aphids. Small, soft-bodied insects that cluster on new growth and undersides of leaves. They suck plant sap and excrete sticky honeydew. Control with strong water sprays, insecticidal soap, or by encouraging beneficial insects.
Hornworms. Large, green caterpillars that can rapidly defoliate plants. Hand-pick and remove. Look for dark droppings on leaves as a sign of their presence.
Harvesting Tomatoes
Harvest timing depends on how you plan to use the tomatoes.
For fresh eating. Harvest when fruit is fully colored and slightly soft when gently pressed. Vine-ripened tomatoes have the best flavor. Pick regularly to encourage continued production on indeterminate varieties.
For cooking and canning. Harvest when fully ripe and deeply colored for maximum flavor. Slightly overripe tomatoes work well for sauce.
For storage. Harvest at the mature green or breaker stage (just beginning to show color) and ripen indoors. This extends the harvest season and allows you to pick fruit before problems like cracking or pest damage occur.
End of season. Before frost, harvest all remaining fruit. Green tomatoes will ripen indoors if placed in a warm location. Store at room temperature, not in the refrigerator. Place green tomatoes in a single layer or wrap individually in newspaper. Check regularly and use as they ripen.
Unripe green tomatoes that do not ripen can be used for cooking. Fried green tomatoes are a classic preparation where sliced green tomatoes are coated in cornmeal or flour and pan-fried until golden.
Saving Tomato Seeds
Saving seeds from open-pollinated (non-hybrid) tomatoes allows you to grow the same variety year after year. Hybrid (F1) varieties will not produce plants true to the parent if you save their seeds.
Selection. Choose seeds from healthy, well-formed, fully ripe fruit from vigorous plants. Allow fruit to become very ripe before harvesting for seed saving.
Fermentation method. Cut the tomato in half horizontally and squeeze seeds and gel into a container. Add a small amount of water. Leave at room temperature for 2 to 4 days, stirring occasionally. A layer of mold will form on top, which is normal. This fermentation process removes the gelatinous coating from seeds and kills some seed-borne diseases.
Cleaning. After fermentation, add more water and stir. Viable seeds sink while pulp and non-viable seeds float. Pour off the floating material and repeat until only clean seeds remain.
Drying. Spread clean seeds on a plate or screen to dry at room temperature for about a week. Do not use paper towels as seeds stick to them. Stir occasionally to ensure even drying.
Storage. Store completely dry seeds in paper envelopes in a cool, dark, dry place. Properly stored tomato seeds remain viable for 4 to 6 years or longer.
Health Benefits of Tomatoes
Tomatoes provide numerous health benefits and are valuable both as food and as a source of beneficial phytonutrients.
Lycopene. Tomatoes are one of the best dietary sources of lycopene, a powerful antioxidant that gives red tomatoes their color. Lycopene has been studied for its potential role in supporting cardiovascular health and its antioxidant properties. Cooking tomatoes and consuming them with a small amount of fat increases lycopene absorption.
Vitamins. Tomatoes provide vitamins C and K, potassium, and folate. Vitamin C supports immune function and skin health. Vitamin K is important for blood clotting and bone health.
Fiber. Tomatoes contribute dietary fiber, which supports digestive health.
Low calorie. Tomatoes are low in calories while providing significant nutrition, making them a valuable part of a healthy diet.
Versatility. The ability to use tomatoes in countless ways, raw or cooked, makes it easy to include them regularly in the diet.
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