10 Practical Tips for Growing Tomatoes from Seeds

Tomatoes are among the most widely-grown veggies for home gardeners, thanks to their easy care and delicious results. Homegrown tomatoes’ flavor, texture, and nutritional value are far superior to store-bought produce. Keep reading to find out all about growing tomatoes from seeds.

Most tomato plants have a relatively long growing season, taking between 90-140 days to reach maturity. As such, it’s beneficial to start your tomato seeds indoors in early spring. The exact planting date depends on your USDA hardiness zone. Plant tomato seeds approximately six to eight weeks before your area’s expected last frost date.

Tomato plants need full sun, consistent moisture, and well-draining garden soil that’s rich in organic matter. Depending on which variety you choose to try, tomatoes often reach five or six feet tall. Therefore, it’s critical to support their heavy vines using a tomato cage, stakes, or a trellis.

Best Tricks for Growing Tomatoes from Seed

There are a few vital considerations for planting tomato seeds. Keeping the soil consistently warm during germination and ensuring that young plants receive adequate light will help your seedlings grow strong and healthy.

If you don’t have enough space for a veggie garden or raised beds at home, don’t worry. Tomato plants are incredibly versatile and also grow well in containers. As long as you have a sheltered location with at least six hours of direct sun each day, your potted tomato plants will thrive throughout the growing season.

Growing your own groceries doesn’t have to be hard work. By following these seed starting tips, growing tomatoes from seeds will be an easy and rewarding project. Whether you prefer large, juicy beefsteak tomatoes or sweet, snackable cherry tomatoes, it’s well worth the effort.

How to Grow Tomatoes from Seeds

Sow tomato seeds in early spring, approximately six to eight weeks before your region’s last forecasted frost date. Use a seedling tray with two-inch cells, small peat pots, or repurposed egg cartons to plant your tomato seeds. Your seed starting soil mix should be well-draining and rich in nutrients.

Seed Starting Supplies

• Tomato seeds
• Seedling tray
• Humidity dome
• Grow lights
• Heat mat
• Seed starting potting soil
• Clean spray bottle

Sow tomato seeds a quarter-inch deep and cover them lightly with soil. It’s helpful to pre-saturate the potting soil to avoid disturbing your newly planted seeds. Top the seedling tray with a humidity dome or plastic wrap to retain moisture.

The ideal soil temperature for germinating tomato seeds is between 70-75℉. Since the air temperature is usually higher than soil temperature, using a heat mat to keep the soil consistently warm is beneficial.

Most tomato seeds germinate within five to ten days of planting. Once they sprout, you’ll notice the first set of leaves to emerge, called cotyledons or ‘seed leaves,’ don’t look like normal tomato leaves. In fact, they’re part of the plant embryo that develops within the seed. True tomato leaves appear within a few days of sprouting.

Provide your seedlings with at least six hours of bright light daily. If you have them on a south-facing windowsill, it’s beneficial to rotate the tray regularly, so the seedlings lean toward the light in different directions. The movement helps establish strong stems. If you don’t happen to have a sunny spot available, use a grow light to prevent the seedlings from becoming elongated or “leggy.”

Transplanting Tomato Seedlings Outdoors

Before transplanting your tomato seedlings, it’s critical to harden them off. Expose them to direct sunlight, wind, and varying temperatures for progressively longer periods over a week or two. Doing so helps avoid transplant shock by allowing the plants to adjust to the harsh realities of outdoor life gradually.

Transplant tomato seedlings outdoors one or two weeks after your area’s average last frost date, once the nighttime temperatures stay above 55℉. Apply a generous layer of dark-colored mulch or a sheet of black plastic over your garden soil about one week before transplanting to warm up the ground.

Once your soil temperature is consistently above 65℉, dig a hole roughly twice the size of the root ball and half the depth of the stem. Add two tablespoons of organic, all-purpose fertilizer to the bottom of the planting hole.

For the best results, trim off all the leaves from the lower third of the tomato plant’s stem and set it into the hole. Gently fill in around the stem and root ball with a 50/50 mixture of compost and garden soil, then thoroughly water it in. The plant will begin growing roots from nodes on its stem called root initials.

Best Soil for Growing Tomatoes

Supporting a healthy soil culture is a vital element of successful home gardening. By providing your plants with nutrient-rich soil that’s aerated and drains well, you’ll be less reliant on treatment products like fertilizers and pesticides.

Cover your garden soil with several inches of well-rotted compost or manure in late fall, then add a thick layer of mulch. Covering the soil throughout the winter protects it from erosion and warms it up faster in the springtime. During spring rains, nutrients from the compost steadily seep into the earth.

Healthy soil contains an extensive microbial network that plays a crucial role in converting organic matter into nutrients that plants can consume. As such, it’s best not to till heavily every year. Deeply tilling the soil kills off most of these beneficial organisms.

Instead, practice mulching in autumn and only till your garden if the soil becomes too compacted. Avoid compressing the ground by using established pathways to move through your garden so you’re not walking on top of plants’ roots.

To grow tomatoes in containers, use a potting mix rich in nutrients and organic matter. Look for a soil blend with added perlite for drainage, coconut coir or peat moss for moisture retention, and compost or fertilizer for plant food.

Choosing the Right Fertilizer for Tomato Plants

Plant fertilizer contains three principal macronutrients: nitrogen (N), phosphorus (P), and potassium (K). Nitrogen boosts green leafy growth; phosphorus encourages robust root systems; potassium supports fruiting and flowering processes.

Feed young tomato plants with all-purpose organic fertilizer. During the first few weeks after transplanting, remove the flowers to direct the plant’s energy toward growing leaves and stems. Once it reaches two-thirds of its mature size, allow the blooms to develop and switch to a fertilizer with greater phosphorus and potassium levels.

Apply granular fertilizer once every three or four weeks throughout the growing season according to the instructions listed on the product label. It’s also helpful to mulch around the plant’s base with coffee grounds and crushed eggshells. They fix calcium and nitrogen in the soil and repel pests like aphids, rodents, and slugs.

Growing Tomatoes in Containers

Growing tomatoes in pots is advantageous for a variety of reasons. You can grow veggies in small spaces and move them around as needed. Container gardening also gives the gardener more control over the plants’ growing conditions by allowing you to adapt to changing environmental aspects throughout the growing season more easily.

Plant tomatoes in a pot that holds at least five gallons of soil to allow ample space for healthy root development. A mature plant will only grow as large as its root system allows. Therefore, a larger container means a larger tomato plant.

Use a pot with drainage holes at the bottom to avoid potential problems with fungal disease and root rot. A dark-colored container keeps the soil warmer, which is advantageous for growing tomatoes in cooler climates.

Best Way to Stake Tomato Plants

Most tomato varieties require additional support once they begin fruiting. To decide whether you should use staking, trellising, or a tomato cage, determine whether your tomato plant is determinate or indeterminate.

Determinate tomatoes have a somewhat compact, bush-like growth habit and eventually reach a maximum size where they stop growing and begin flowering. They tend to set all of their fruit at once. While a few determinate varieties don’t require staking, it’s usually beneficial to use a tomato cage to prevent accidental plant damage.

Indeterminate tomatoes continue growing and producing fruit as long as their environmental conditions allow. Some varieties stay smaller than others. Regular pruning helps maintain adequate airflow, control the plant’s size, and stimulate healthy new growth. Tomato cages are often too small to support indeterminate tomato types. Staking or trellising typically works best, especially for cherry tomatoes.

Insert the tomato cage or plant stakes right after transplanting while the plant is still small. Doing so minimizes breakage and damage to the roots. Alternatively, place a trellis behind your tomato plants and loosely tie the branches to the frame as they grow longer.

Harvesting Tomatoes

Most tomato varieties begin producing fruit within approximately 90 days of transplanting. Harvest tomatoes as soon as they ripen for the best possible flavor and to encourage further fruit production.

There are a wide variety of tomato cultivars available that ripen to red, orange, purple, or yellow. In most cases, it’s safe to gently pull ripe tomatoes off the vine. However, if you feel any resistance, use a sharp pair of scissors to keep from accidentally breaking the branch.

If you still have loads of green tomatoes at the end of your growing season, check for light-colored streaks coming from the bottom or blossom end. These streaks mean that the ripening process has begun and the tomato will continue maturing off the vine. Placing green tomatoes in a paper bag along with an apple, avocado, or banana helps them ripen faster because these fruits release ethylene gas.

How to Regrow Tomatoes

Have you ever wondered how to regrow tomatoes from tomatoes? Although it might sound odd, it’s possible to regrow most tomato branches.

Tomato stems often develop root initials, also called adventitious roots. These make it possible to transplant a broken branch and grow it into a new tomato plant. Look for white or light green nodes on the stem to tell whether you can regrow it.

To regrow tomatoes from a cutting or broken branch, begin by removing all the existing flowers and fruit. Then, pinch off the leaves from the lower half of the branch. Fill a well-draining one-gallon container with potting soil and insert the stem up to where you’ve removed the leaves. Keep the soil consistently moist, and the branch will develop roots within a few weeks.

Common Pest and Disease Problems for Growing Tomatoes

Healthy plants are considerably more resilient than stressed ones. Ensuring that your plants receive sufficient light, water, and nutrients is their best defense against pests and plant diseases. Some of the most commonplace tomato growing problems come from nutrient deficiency rather than insects or pathogens.

Blossom end rot, which appears as a waterlogged brown spot on the fruit’s bottom, results from calcium deficiency. Immediately remove any fruit with blossom end rot. Earthworm castings, bone meal, and rock phosphate are effective remedies.

The most prevalent insect pests that attack tomatoes include aphids, spider mites, slugs, and tomato hornworms. To get rid of small insects like aphids and mites, spray all plant parts with an organic pesticide like neem oil, horticultural oil, or insecticidal soap. Be sure to cover the leaves’ undersides, as that’s a favorite hiding spot for insects. Apply an abrasive mulch like crushed eggshells or coffee grounds to deter slugs. Repel tomato hornworms with companion planting.

Septoria leaf spot and powdery mildew are widespread fungal diseases that frequently affect tomato plants. The first symptoms of leaf spot are small brown or black spots that quickly spread and develop a grey or tan center. Powdery mildew forms a fuzzy white coating on the leaves and stems.

The best way to prevent the spread of plant diseases in your garden is to provide adequate air circulation and limit splashing water on the plants’ leaves by using drip irrigation. Spray affected plants with organic copper or sulfur fungicide at the first sign of infection.

Companion Plants for Tomatoes

Companion planting is a garden design strategy that takes advantage of the mutually beneficial relationships between certain plants. Some plant pairings work to attract beneficial insects, repel pests, and enhance their neighbors’ flavor and overall growth. However, other plants don’t get along well and must grow in separate areas.

Marigolds deter ants, aphids, thrips, tomato hornworms, whiteflies, and harmful soil nematodes. They also attract pollinators and provide valuable habitat for beneficial predatory insects like hoverflies, ladybugs, and parasitic wasps (which don’t sting humans).

Aromatic herbs like basil and dill work to repel insect pests like aphids, tomato hornworms, and whiteflies. Many gardeners report that basil also enhances tomatoes’ flavor when planted nearby.

Leafy greens with shallow roots like arugula, lettuce, and spinach grow well between tomato plants. Their broad leaves act as living mulch to retain moisture and insulate the soil in the summer heat.

Avoid planting your tomatoes near brassicas like broccoli, Brussels sprouts, cabbage, cauliflower, and kale. These plants reportedly inhibit one another’s growth. Additionally, other members of the nightshade family like eggplants, peppers, and potatoes should also grow in a different area of the garden since they’re susceptible to similar pest and disease problems.

Growing your own tomatoes is an enjoyable and rewarding endeavor. You’ll be hooked after your first harvest of juicy, delicious homegrown tomatoes. It’s like getting a taste of sweet summer sunshine with each bite. Besides being more nutritious and flavorful, growing tomatoes from seed gives you the opportunity to try unusual tomato varieties that aren’t available at the supermarket.

Do you have any questions or comments about growing tomatoes from seed? Let me know in the comments! If you enjoyed these tomato growing tips, please share this post about how to grow tomatoes from seeds with your fellow green thumbs.