How To Grow Tomatoes From Seed: Step-By-Step Guide For Beginners

Harvesting homegrown veggies is one of the most satisfying things in the world, and even more so when you start from scratch – from seed, to be more precise. Getting those healthy, juicy tomatoes from your kitchen garden isn’t hard if you’re familiar with some basic steps. If this is your first time, we’d recommend that you follow the conventional steps below to ensure a thriving crop. 

How To Grow Tomatoes From Seed

Continue reading, and you’ll find some expert advice on sowing, growing, and harvesting tomatoes. Besides the basic steps on growing tomatoes from seed, you’ll also find some hands-on tips to make sure you get loads of beautiful tomatoes for salsas, sauces, and salads – not to mention the juicy snacks they make when eaten fresh off the vine! 

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Why Grow Tomatoes From Seed?

Gardening is a healthy, satisfying, enjoyable, and productive hobby. Most gardeners always keep their vegetable gardens lush with the varieties of the season. If you’re looking for some extra motivation to grow tomatoes from seed, here are some reasons why it’s definitely worth your time:

Delightful Harvest

Most gardeners grow tomatoes from scratch for the delightful experience of plucking fresh, ripe tomatoes off the vine. Once you take a bite of those juicy fruits, you’ll be growing them season after season without looking for reasons!

Tastier And Healthier

Homegrown tomatoes are juicer, fresher, and much healthier than store-bought ones. They’ll add much more flavor to pasta, salads, and all your everyday recipes.

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Bundles Of Choices

One of the main reasons for starting from seeds is to try out some unique varieties that you don’t usually find in the produce section. Nursery seedlings will also have limited options. With seeds, you can choose among a wide range of tomatoes. From large beefsteak tomatoes, perfect for a classic hamburger, to green tomatoes and cherry tomatoes, you’ll have lots of options available. 

Growing Tomatoes From Seed

Moving on to the fun part, let’s grow some tomatoes! Follow the guide on growing tomatoes from seed before you get started. You’ll learn how to start the seeds, take care of the young seedlings, watch them grow, and harvest loads of tomatoes!

Equipment You Will Need

How To Grow Tomatoes From Seed

Before getting started, you’ll need some basic equipment to start the seeds. The right set of equipment makes the task easier, faster, and much more productive. 

So here’s what you’ll need:

Spray Bottle

Watering cans and hoses are perfect for watering plants in garden beds, but they’ll easily drench a small seed tray. A spray bottle is a better option to moisten the soil at just the right level for starting the seeds without letting them get too wet.  

Seed Tray

Small seed trays with a two-inch depth are perfect for starting tomatoes. Though you can repurpose take-out containers or paper cups, a standard seed tray will offer just the right size and can be reused season after season for starting your vegetable crops. 

Heat Propagator

Tomato seeds germinate best at a temperature between 70 to 80 degrees Fahrenheit. Outside this ideal range, germination is either slow or may fail completely. To maintain a steady soil temperature at just the right level for the tomato seeds to germinate, you’ll need a heat propagator. Irrespective of the surrounding temperature changes, a heat propagator will provide steady warmth for the seeds to sprout and for the seedlings to develop.

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Plant Labels

Plant labels are a must-have if you want to remember the varieties you’re growing! Use a soft pencil to label the types since pens and markers will fade. 

Seed Starting Mix

Never use garden soil in your seed trays. It’s heavy and can easily become compacted after watering. Tomato sprouts will have a hard time breaking out of hard, packed dirt. Instead, choose a quality seed starting mix to fill into the trays. This light, friable soil often also contains compost for a nutrient-rich home where seedlings can develop with ease.

Tomato Seeds

You can ferment seeds at home from store-bought tomatoes or buy pre-packaged tomato seeds. Pre-packaged tomato seeds offer more variety and increase the chances of success. Tomato Seeds older than 3 to 4 years lose their viability. Make sure you get your tomato seeds from a reliable source, so there are fewer chances of failure or diseases. Make sure to check store brought tomato seeds to make sure they are the right tomato varieties.

You can choose between determinate and indeterminate tomato varieties. Determinate varieties grow shorter and mature all their fruits at once. Indeterminate varieties grow taller and allow a longer harvest season. 


A small hand trowel will make it easier to handle soil.

Liquid Fertilizer

Once the tomato seedlings are up, they’ll need regular doses of diluted liquid fertilizer to develop. 

Step-By-Step Tomato Seed Starting Guide

How To Grow Tomatoes From Seed

Now that you have the right equipment, you’re ready to learn how to grow tomatoes from seed! The step by step guide will tell you how to sow the tomato seeds, help them sprout, and care for the tomato seedlings until they are strong enough for transplanting in the garden. 

Let’s see how to go about it:

Wait For The Right Time

Most gardeners do not have a long enough growing season in their region to start seeds outdoors. Tomato seeds are sown around 10 weeks before they can go in the garden when the soil temperature outdoors is at least 55°F and nighttime temperatures do not dip below 50°F this is usually after the last frost date.

Prepare The Containers

Dampen the seed starting potting mix with water before adding it to the containers. Add water gradually, mix it in as you go. Once the potting soil can be compressed by hand but still breaks apart when you poke it, and water is not dripping from it, you have just the right consistency. 

Make sure the container has drainage holes at the bottom. For repurposed pots, you can poke holes at the base with a sharp knife. Transfer moistened soil to the seed tray until it’s about an inch from the top. Prepare all your seed trays in the same way. 

Plant The Seeds

Sow 3 to 4 seeds in each tray, pressing them to a depth of ¼ inch below the surface. You can thin them to a single strongest seeding once they’re about 2 inches in height. Tomato seeds are tiny, so be careful not to push them in too deep, or you’ll probably never see them again. Always sow dry tomato seeds. Once they absorb moisture from the soil, they get sticky and bind well with the soil particles. Label the varieties you’ve planted. 

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Place In A Heat Propagator

At this point, you’ll need to place the containers at a warm location to help the seeds germinate. A heat propagator is the best option since it provides a consistently warm, humid environment. Place the containers over the propagator tray, with the cover on top. Set the temperature at 77°F and make sure all the vents are closed. 

Monitor Until Sprouting

Check the tray daily, making sure the soil is moist. Since a heat propagator will provide a humid environment, you’ll rarely need to provide additional moisture. With the right conditions, tomato seeds typically take between 5 to 10 days to germinate. As soon as you see sprouts appear, open the vents halfway. When most of the sprouts have true leaves, open the vents completely. 

Provide Light

After germination, seedlings will need adequate lighting to develop optimally. If your heat propagator comes with grow lights, turn them on. If not, you can move the propagator to a sunny window sill. In regions with warm sunshine, you can lift the propagator cover completely. I personally use a sunny window or greenhouse to start my tomato seedlings.

Care For Tomato Seedlings

How To Grow Tomatoes From Seed

Take good care of them to help them develop strong roots. Keep the soil evenly moist; spray it with water whenever the topsoil is dry. Rotate the trays if you find the plants leaning to one side, and make sure all of them get a fair share of sunlight every day. Once the seedlings develop true leaves, start feeding them once each week with liquid fertilizer, prepared at half the recommended strength mentioned on the fertilizer package. 

Potting On

Since seed trays have limited soil medium, the seedlings will soon need to be “potted on” – which means the tomato seedlings need to be transplanted to a larger container. Once they have two sets of leaves and are strong enough to handle them, the tomato seedlings are ready to come out of the propagator for potting on.

It’s best to pot on in stages. Move them to a slightly larger container, first when they have two sets of leaves and then a second time, three weeks later.

Handle delicate seedlings with care, preferably from their leaves rather than the stems, since they can be easily bruised.

Hardening Off

Once the tomato plants are at least 6 inches tall and there’s no danger of frost, they’re ready to be planted out in the garden. Gradually acquaint them with the outdoor conditions, exposing them to the sun for a short period each day. Increase the number of hours the plants stay outside slowly each day until, in about a week, they are ready to go in the garden bed.

Plant In The Garden

Choose a sunny spot for your tomato plants. For southern regions, light afternoon shade will work better. Prepare a well-drained, fertile bed for the young plants by mixing in plenty of compost. Space the transplants 2 feet apart, with 4 feet between rows. Dig planting holes and bury the plants deeper in the ground than they were sitting in the pot, covering some of the stem with soil, all the way up to the lowest set of leaves. 

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Tomato plants will need support as they grow taller. Install stakes at the time of planting to avoid damaging the roots of established plants. Water the transplants. Ideally, shade the newly planted transplants to prevent the leaves from drying.

How To Care For Tomatoes

How To Grow Tomatoes From Seed

Now you know how to grow tomatoes from seed and set the plants in the garden. Once the tomato plants are in their final home, they’ll need consistent care to develop. Here are some things you need to pay attention to:


Water generously during the first few days that you set the transplants in the garden. Throughout the growing season, regular watering will be required. Offer about 2 inches of water each week throughout the summers, if there hasn’t been any rain. 


Mulch the ground around the plants once the ground has warmed up. Mulching too early will leave the soil cool, unsuitable for your tomatoes. Apply a 2 to 3-inch layer of organic material, such as straw or grass clippings. 


Continue feeding diluted liquid fertilizer regularly throughout the growing season. However, be careful not to overfeed, and use low-nitrogen fertilizer. Too much nitrogen may give lush growth, but the plants won’t bear as many fruits.

Pests And Diseases

Keep an eye out for pests attacks! Unfortunately, tomato plants are susceptible to infestations, particularly tomato hornworms and whiteflies. You can get rid of them by hosing them off with a strong stream of water, handpicking and destroying or applying insecticidal soap. Fungal diseases can be prevented by avoiding damp conditions. Water just enough to moisten the soil, and avoid drenching the foliage while doing so.

Harvesting Fresh Tomatoes

How To Grow Tomatoes From Seed

That’s all on growing tomatoes from seed. But the best part is yet to come! Once you’ve grown some healthy plants, they’ll bear those red, juicy tomatoes you had been waiting for all season!

Leave them on the vine till they become very red throughout the surface but are still firm. If you’ve grown yellow, orange, or green varieties, harvest them once they turn the right color and grow to the correct size. Typically, they’re ready for picking in about 50 to 80 days from transplanting, depending on the cultivar.

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