Step-by-step instructions for sowing tomato seeds: How to successfully plant and nurture your own tomato plants.


Sowing tomato seeds is a crucial step in successfully growing your own delicious tomatoes. This guide will provide you with step-by-step instructions on how to sow tomato seeds and ensure their healthy germination and growth.

Begin by choosing the right time to sow your tomato seeds. Tomatoes thrive in warm temperatures, so it is best to start sowing them indoors about 6-8 weeks before the last frost date in your area. This will give the young tomato plants enough time to grow before being transplanted outdoors.

Next, gather all the materials needed for sowing tomato seeds. You will need seed trays or containers with drainage holes, potting soil, labels for labeling the different tomato varieties, and a heating mat or heating pad to provide bottom heat. Tomato seeds germinate best between 75-85°F (24-29°C).

Moisten the potting soil before filling the seed trays or containers. Fill them with the pre-moistened soil, leaving about ¼ inch (0.6 cm) of space at the top. Make small holes in the soil with your finger or a pencil, about 1/4 inch (0.6 cm) deep and 1 inch (2.5 cm) apart. Place a tomato seed in each hole and gently cover it with soil.

After all the tomato seeds have been planted, lightly water the soil surface to settle it. Place the trays or containers on a heating mat or heating pad, and if needed, cover them with a plastic bag or a plastic dome to create a greenhouse-like environment. Keep the soil consistently moist, but not soaking wet.

Once the tomato seeds start to germinate, usually within 7-10 days, remove the plastic cover and move the trays or containers to a bright location. A south-facing window or a grow light will provide the young tomato plants with the necessary light they need to grow.

As the tomato seedlings grow, thin them out by removing the weaker and slower-growing plants. This will ensure that the remaining tomato plants have enough space to grow and develop strong stems and leaves.

Continue to provide the tomato seedlings with ample light, warmth, and water. As they grow, you may need to transplant them into larger pots to accommodate their growing root systems. When the outdoor temperatures are warm enough and there is no more danger of frost, gradually acclimate the tomato plants to the outdoor environment by placing them outside for a few hours each day.

By following these step-by-step instructions, you will be able to successfully sow tomato seeds and grow healthy, vigorous tomato plants that will provide you with an abundance of delicious tomatoes.

Stay tuned for more tips and recipes on how to make the most of your home-grown tomatoes!

10 Must-Know Tips for Growing Tomato Seedlings to Plant in Your Garden

When it comes to seed-starting, tomatoes are really one of the most popular plants to grow. They are tasty, versatile, and can be grown in a variety of climates. If you’re looking to start your tomato seedlings for planting in your garden, here are 10 must-know tips to ensure success:

1. Choose the right variety: There are many different types of tomatoes to choose from, such as heirlooms, cherry tomatoes, and slicers. Consider your local climate and personal preferences when choosing the variety to sow.

2. Start sowing early: Tomatoes take time to grow, so start sowing the seeds indoors about 6-8 weeks before your last frost date. This will give them enough time to grow into sturdy seedlings.

3. Use seed-starting mix: For best results, use a seed-starting mix rather than regular potting soil. This mix is lighter and provides better drainage for the delicate tomato seedlings.

4. Label your containers: It’s important to label your containers with the tomato variety and sowing date. This will help you keep track of your seedlings and know when they should be transplanted into the garden.

5. Provide heat: Tomato seeds need warmth to germinate, so place your seed trays on a heating mat or in a warm location. This will help speed up the germination process.

6. Water lightly: Keep the soil moist but not soaking wet. Over-watering can cause the seeds to rot, so water with a spray bottle or mist them gently.

7. Give them light: Tomato seedlings need plenty of light to grow strong. Place them near a south-facing window or use grow lights if you don’t have enough natural light.

8. Don’t fertilize right away: Wait until the second set of leaves appear before you start fertilizing your tomato seedlings. Use a diluted, balanced fertilizer to avoid burning the delicate plants.

9. Harden off before planting: A week before transplanting, gradually acclimate your seedlings to the outside environment by exposing them to sunlight and wind for a few hours each day. This will help them adjust and avoid transplant shock.

10. Choose a sunny spot in your garden: Tomatoes love sunshine, so choose a location in your garden that receives at least 6-8 hours of direct sunlight. This will ensure that your tomato plants produce abundant fruit.

By following these tips, you’ll be well on your way to growing healthy and productive tomato seedlings to plant in your garden. So, plan ahead, sow your seeds, and get ready to enjoy the benefits of homegrown tomatoes!

1 Don’t Start Too Early

If you’re planning to sow tomato seeds indoors, it’s important not to start too early. Starting tomato seeds too soon can result in spindly, weak plants that may struggle to survive once transplanted outdoors.

When determining the best time to start sowing tomato seeds, consider the variety you’re growing and the average number of days it takes for the seeds to germinate. Tomato seeds typically take around 7 to 10 days to germinate, so you should plan to start sowing seeds indoors about 6 to 8 weeks before the last frost date. This will provide enough time for the seedlings to grow and develop before they are ready to be transplanted into the garden.

Prepare the potting containers or trays by filling them with a seed-starting mix. Choose containers that have drainage holes at the bottom to ensure proper water drainage. The diameter of the containers should be about 2 to 3 inches, which is ideal for tomato seedlings.

Sow the tomato seeds about 1/4 inch deep in the potting mix, spacing them about 1 to 2 inches apart. Lightly cover the seeds with additional potting mix and gently press it down to ensure good seed-to-soil contact.

After sowing the seeds, place a plastic cover or a waterproof tray over the containers to create a greenhouse-like environment that will help retain moisture and provide the necessary warmth for germination.

Keep the potting mix consistently moistened but not waterlogged. Tomato seeds need a warm and moist environment to germinate successfully.

As the seedlings start to emerge, remove the plastic cover and move the containers to a bright location with indirect sunlight. Tomato seedlings require a minimum of 12 to 14 hours of light per day to grow healthily.

Once the seedlings have developed their first true leaves, thin them out by snipping off the weaker ones to ensure that each seedling has enough space to grow. Thin seedlings should be discarded or used for culinary purposes.

Eventually, after a couple of weeks, your tomato seedlings will be ready to be transplanted outdoors. Before moving them, it’s important to acclimate them to outdoor conditions. This process, known as hardening off, involves gradually exposing the seedlings to outdoor elements like sunlight, wind, and temperature changes over the course of several days.

Congratulations! You’ve successfully sown tomato seeds indoors and nurtured the seedlings into healthy, vigorous plants ready to be transplanted outdoors. Now you can look forward to a season full of delicious homegrown tomatoes!

For more FAQs and step-by-step instructions on growing tomatoes, visit our website and explore our gardening resources.

2 Keep Seeds Warm

Once you’ve chosen your tomato varieties and have your soilless growing medium ready, it’s time to start sowing the seeds. But before you can begin, you need to create the right environment for your tomato seeds to germinate. Tomato seeds need a warm temperature to sprout and develop into vigorous plants.

To keep the seeds warm, you can use a seedling heat mat. This mat is designed to provide a consistent temperature for the seeds, which helps them germinate quickly and evenly. You can place the heat mat underneath the seed trays or pots where you’ve sown the tomato seeds.

If you don’t have a heat mat, you can still create a warm environment for your seeds. One option is to place the seed trays or pots on top of a radiator or any other warm surface. Another option is to cover the trays or pots with a waterproof plastic cover to trap the heat and create a greenhouse effect. Just make sure to keep an eye on the temperature and adjust accordingly.

It’s important to keep the seeds warm throughout the germination process, which can take up to 10 days. Check the temperature regularly and make adjustments as needed. Remember, a warm and consistent environment will help the seeds germinate faster and ensure a higher germination rate.

3 Light Them Up

Once your tomato seeds have germinated and the young seedlings have started to grow, it’s time to provide them with the light they need to thrive. This step is crucial because without enough light, your tomato plants may become leggy and weak.

If you’re growing tomatoes indoors, place them near a bright window where they can receive at least 6-8 hours of direct sunlight each day. If natural light is not sufficient or available, you can use artificial grow lights. These lights, specifically designed for plant growth, provide the necessary spectrum of light that tomatoes need to grow and produce healthy fruits.

When using grow lights, it’s important to keep them at the right distance from the seedlings. Hang the lights about 2-4 inches above the tops of the plants, adjusting the height as the seedlings grow. This will prevent the seedlings from getting too leggy and ensure they receive adequate light for healthy growth.

Another helpful technique is to use reflective materials around the plants to maximize the amount of light they receive. This can include using aluminum foil or reflective panels to redirect light back onto the plants.

As your tomato plants continue to grow, it’s important to provide support for their stems. This can be done by gently inserting stakes or cages into the soil near the plants and tying the stems to them as they grow. This will help prevent the plants from falling over and provide support for the heavy fruits they will eventually produce.

Keep in mind that as your tomato plants grow, they will need more water and nutrients. Make sure to water them regularly, keeping the soil evenly moist but not waterlogged. Fertilize the plants every 10-14 days with a balanced fertilizer to provide them with the necessary nutrients they need for healthy growth.

By following these steps and providing adequate light, support, and nourishment, your tomato plants will thrive and produce a bountiful harvest of delicious fruits. Now that you know how to sow tomato seeds and care for the seedlings, you can enjoy the journey of growing your own tomatoes from start to finish.

✿ Read More: Gardening Tips and Advice.

Dr Heidi Parkes

By Dr Heidi Parkes

Senior Information Extension Officer QLD Dept of Agriculture & Fisheries.