Growing Tomatoes from Seed to Harvest

By: Jessie Keith


Nothing is more gratifying than a big tomato harvest in the summer season!

Tomatoes are the most popular warm season crop, coming in loads of colorful, tasty varieties for gardeners to try. It pays to grow your own from seed, because they are easy and inexpensive to raise and homegrown summer tomatoes taste better. That’s why most new vegetable gardeners start with these fruits.

Tomato Basics

  • Common Name: Tomato
  • Botanical Name: Lycopersicon esculentum (syn. Solanum lycopersicum var. lycopersicum)
  • Days to Harvest: 65 to 85 days after planting
  • Soil: Rich, porous, friable loam amended with Black Gold Garden Compost
  • Pests: Tomato hornworms and Colorado potato beetles feed on foliage and fruits causing significant damage.
  • Diseases: Seedling death caused by Pythium and Phytophthora pathogenic fungi, and plant wilt or poor performance due to fusarium wilt, tomato mosaic virus, and verticillium wilt are common disease problems.
  • Disorders: Blossom end rot (caused by calcium deficiency), splitting/cracking (caused by excessive water or temperature fluctuations), and fruit toughness, cat-facing, and reduced productivity (caused by cool temperatures) and the most common disorders.
  • Planting Time: After the last frost date, in temperate zones; in subtropical or tropical climates they can be planted any time of year.
  • Fertilization: Feed at planting time with an organic fertilizer formulated for tomatoes.


Days to Harvest Timeline

'Pomodoro' is a fantastic all-purpose tomato for fresh eating and cooking.

‘Franchi’s Italian Pear’ is a fantastic all-purpose tomato for fresh eating and cooking.

Starting Seeds

It takes around six to eight weeks to grow tomatoes from seed to ready-to-plant seedlings. Start seeds indoors for best results.  Sow seeds in cells filled with seedling mix and lightly sprinkle a bit on top to cover. Gently moisten the cells with water and place right under the warmth of grow lights. In 5 to 12 days your tomato seeds should germinate. Germination is best in warm temperatures (68° to 75° Fahrenheit (20-24° Celsius)). A heat mat for seed starting will dramatically hasten germination. (Click here for detailed seed-starting instructions.)

Tending Seedlings

Tomato seedlings are delicate and have two lance-shaped seed leaves when they first emerge. The true leaves, which are feathery and divided, appear in 2 to 3 days; at this point feed seedlings with a diluted, water-soluble tomato fertilizer. Keep the soil moist but not wet. Wet soil can encourage fungal disease that causes seedlings to rot or “damp off.” To avoid leaf burn, lift grow lights up as plants get closer to the bulbs.

Tending Small Plants

Happy tomato seedlings

Tomato plants should be around 8- to 10-inches tall and garden ready after eight weeks. Indoor grown seedlings are very tender, have weak stems and need time to adjust to full sun. If directly planted outdoors they will develop leaf burn, so they need to be hardened off for at least a week before planting. Hardening off means acclimating seedlings from their cushy indoor growing conditions to the windy, sunny outdoors where temperatures fluctuate greatly.

To harden seedlings off, place the potted plants in a protected spot that gets a few hours of sun per day. Each day move them to a new location where they get a little more light and wind each day. After a week or so, they should be tough enough to plant in the garden.

'Matt's Wild Cherry' is a delicious, tiny cherry tomato with big flavor.

‘Matt’s Wild Cherry’ is a delicious, tiny cherry tomato with big flavor.

Garden or Container Planting

Choose a good spot for your tomatoes. They require at least 8 hours of full sun and well drained soil that’s fertile. Vining (indeterminate) types need caging or trellising, while bush (determinant) types need staking; both types benefit from summer pruning.

Before planting in the garden, amend beds by digging and turning the soil deeply and adding rich compost and an OMRI Listed tomato fertilizer. Plant tomatoes around 4 feet apart and mulch with a 2 to 3 inch layer of Black Gold Natural & Organic Compost Blend. Young plants can be planted deep, with only a couple of nodes with foliage above ground, but leaves should be gently removed from all stem parts that will be covered with soil. Water regularly to keep plants moist, not wet.

Tomatoes are such aggressive feeders and water hounds, you have to give serious attention to container-grown plants. Start with a really large pot. Determinant tomatoes are best, but indeterminates will also work if you keep them caged and pruned. A good water-holding potting soil is perfect for container culture. I recommend Black Gold® Natural & Organic Potting Mix, which also contains Resilience™ for stronger stems and better root development. Container-grown tomatoes need to be watered daily and fed more frequently, but if you give them ample attention, they should thrive and produce beautifully.



Tomato fruits develop the best when days are warm (between 78 and 92 degrees Fahrenheit) and nights are warm (at least 70 degrees Fahrenheit). Tomatoes can be harvested green for fried green tomatoes and green tomato chutney, but they are best picked fully colored and ripe. Some tomatoes are naturally easy to pull from the vine when mature, while others cling to the vine. I always keep a pair of harvest sheers on hand for clingers. If you accidentally harvest a few fruits with a bit of green, let them stand on a sunny window for a couple of days, and they will ripen up right away.


Tomatoes can be cut back and shaped to keep them from overtaking a trellis or container. Use sharp, clean pruners to cut whole branches back to main stems as needed. Try to maintain productive, fruit and flower laden branches, if at all possible. As a precautionary measure, it is wise to dip pruners in a 10% bleach solution when pruning from plant to plant, just to avoid the possibility of spreading disease. Dip and wipe the pruners after pruning one plant and going to another.

Tomatoes to Try

'Gold Medal' is one of the best-tasting, prettiest beefsteak tomatoes.

Gold Medal’ is one of the best-tasting, prettiest beefsteak tomatoes.

Tomatoes come in all colors, shapes, and sizes and flavor is surprisingly variable. In my garden I always choose several slicers, sauce tomatoes, salad tomatoes, and cherries each year. This year’s pickings include the heirloom red and yellow slicer ‘Gold Medal‘, the French salad tomato ‘Crimson Carmello‘, and orange beefsteak ‘Kellogg’s Orange Breakfast‘. My favorite sauce tomatoes are the Italian powerhouses ‘Red Pear‘, ‘San Marzano Redorta‘ as well as the salad-sized ‘Principe Borghese‘, which is touted as the best tomato for sun drying. My cherry tomatoes of choice are the sweet, golden ‘Sun Gold‘, tiny red ‘Matt’s Wild Cherry‘ and delectable yellow and red ‘Isis Candy‘.  All are beautiful and have exceptional flavor. Here are the basics for starting, growing, protecting, and harvesting your tomatoes for success and high yields.

Enjoy Your Tomatoes

This is the easy part. Lavish burgers with big, hearty tomato slices, eat them fresh in salads or make homemade tomato sauce  and salsa. To extend the season, freeze whole tomatoes and sauce for winter. (This generally requires at least 10 healthy tomato plants to provide enough to store all winter.) Growing tomatoes is gratifying if you follow the proper steps and give them the best care. If you do it right you should have more than enough tomatoes to enjoy and share. I wish you the best tomato season!

Follow these instructions and you'll have enough tomatoes for storing and sharing with friends.

Follow these instructions and you’ll have enough tomatoes for storing and sharing with friends.

About Jessie Keith

Plants are the lens Jessie views the world through because they’re all-sustaining. (“They feed, clothe, house and heal us. They produce the air we breathe and even make us smell pretty.”) She’s a garden writer and photographer with degrees in both horticulture and plant biology from Purdue and Michigan State Universities. Her degrees were bolstered by internships at Longwood Gardens and the American Horticultural Society. She has since worked for many horticultural institutions and companies and now manages communications for Sun Gro Horticulture, the parent company of Black Gold. Her joy is sharing all things green and lovely with her two daughters.

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