Growing your own tomatoes from seed is easier than you think! Plus, you can get a jump on the season if you start them indoors.
Starting from seed also allows you to select unique varieties, control the plant’s growth from the beginning, and save money while growing a garden full of delicious, healthy tomatoes.
Follow these simple steps to go from seed to harvest whether you’re direct sowing or starting indoors!


1. Select Your Tomato Variety
Selecting the right variety is your first step to success. Growing tomatoes from seed gives you access to an incredible range of choices—heirloom, hybrid, and specialty types—many of which you can’t find as starter plants.
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Celebrity Hybrid Tomato Seeds: Known for its disease resistance and balanced flavor, this hybrid is a dependable choice for gardeners of all levels.
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Early Girl Tomato Seeds (Hybrid): A fast-maturing variety that produces flavorful, medium-sized fruits perfect for fresh eating.
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Organic Roma Tomato Seeds: An excellent choice for sauces, canning, and cooking, with a rich, meaty texture.
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Sakura Organic Cherry Tomato Seeds: A sweet and prolific cherry tomato variety that’s perfect for snacking and salads.
Choose varieties that best suit your taste and growing conditions. Think about the size and flavor you prefer, whether you’re growing for fresh eating, canning, or cooking, and consider how much space you have available.
Also consider if you’d like determinate or indeterminate tomatoes (fruiting all at once vs all season long).
2. Choose the Right Time
The best time to start your tomato seeds indoors is 6-8 weeks before your area’s last expected frost date. Check your local frost calendar to pinpoint this date and count back to find your starting window.
For example, if your last frost is May 15, aim to plant seeds indoors by mid-to-late March. Avoid starting too early, as this can lead to leggy plants that outgrow their containers before the weather is suitable for outdoor planting.
Late starters might not allow your plants enough time to mature and produce fruit before the end of the growing season.
3. Gather Your Supplies
Before starting seeds indoors, make sure you have:
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Tomato seeds: Expect to spend $3-$6 per packet, depending on the variety and brand. Heirloom and specialty seeds may cost more but offer unique flavors and traits.
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Seed-starting trays or containers: Basic trays or pots can cost $5-$15, while reusable or biodegradable options may run higher.
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Seed-starting mix: A quality mix designed for seeds typically costs $4-$10 per bag. Look for lightweight, well-draining options.
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Light source: A small grow light setup can range from $20-$70, though a sunny windowsill is free if it meets your light needs.
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Watering can or spray bottle: These can cost as little as $2-$10 depending on size and material.
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Labels: Simple labeling materials like popsicle sticks or plastic tags cost around $2-$5 per pack. Alternatively, use recycled materials for free.
For a professional and foolproof seed-starting solution, see our Bio Dome Seed Starting System. It’s ideal for both beginners and experienced gardeners, as it simplifies the process and assists you with high germination rates and minimal effort.
Bio Dome Benefits


4. Plant Your Seeds
Now that you have everything you need, it’s time to start your seeds. Here’s how:
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Prepare Containers: Fill them with moistened seed-starting mix. It should be damp but not soggy.
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Plant Seeds: Place 2-3 seeds in each container, about ¼ inch deep. Cover lightly with soil.
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Water Gently: Mist the top layer to moisten the soil without overwatering. Consistency is key.
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Label: Write the variety name on a label for easy identification.
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Provide Warmth: Keep containers in a warm spot (70-80°F). A seedling heat mat can help maintain consistent temperatures and improve germination.
Pro Tip: Adding a humidity dome, like our Bio Dome, over your containers can further improve moisture retention and maintain the ideal temperature for germination. The dome creates a mini-greenhouse effect, giving your seeds a better environment to sprout.
5. Care for Seedlings
Once your seeds sprout, they’ll need proper light, water, and care to thrive. Here are our recommendations for tomato seedlings care indoors:
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Light: Seedlings need 12-16 hours of light daily. A grow light placed close to the plants prevents them from becoming leggy. Adjust the light height as they grow.
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Watering: Keep the soil consistently moist but not soggy. Water from the bottom when possible to prevent damping-off disease and encourage strong root growth.
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Thinning: Once seedlings have their first true leaves (which look like mature tomato leaves), snip the weaker ones, leaving the strongest plant in each container. This ensures resources go to the healthiest plants.
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Fertilizing: Feed seedlings with a balanced fertilizer every two weeks after the first true leaves appear. This gives them the nutrients they need for strong growth.
6. Transplant to Larger Containers (Optional)
Seedlings may outgrow their initial containers before it’s time to move them outdoors. Some signs they’ve outgrown their containers are roots emerging from the drainage holes, slowed growth, or yellowing lower leaves due to limited nutrients.
Transplant them into larger pots (often referred to as up-potting) to give their roots more room. When transplanting, bury the stems deeper to encourage strong root development. New roots will grow along the buried portion of the stem, creating a sturdier plant.
7. Harden Off Your Plants
About 1-2 weeks before planting your tomatoes in the garden, begin the process of hardening off your indoor seedlings. This involves gradually acclimating them to outdoor conditions to reduce transplant shock:
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Place seedlings outside for a few hours each day, increasing the time gradually.
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Start in a sheltered, shady spot and move them to sunnier, windier areas over time. This process helps them acclimate to outdoor conditions, reducing transplant shock.


8. Plant in the Garden
When the danger of frost is past and the soil is warm, it’s time to plant your tomatoes in the garden. Here are some best practices to get it right:
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Choose a Sunny Spot: Tomatoes require 6-8 hours of direct sunlight each day to produce healthy, flavorful fruits.
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Prepare the Soil: Improve the soil with compost or a balanced fertilizer to provide essential nutrients for growth.
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Plant Deep: Bury the seedlings up to the first set of leaves. This technique promotes root development along the buried stem.
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Space Them Out: Allow 18-24 inches between plants to provide adequate air circulation and room to grow.
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Water Thoroughly: Give the plants a deep watering immediately after planting to help them grow strong roots and adjust to their new environment.
Remember to plan for the position of the sun throughout the seasons. While you might have 8+ hours of sunlight in the spring, some obstructions like roofs and tree branches could mean this is halved in the summer.
9. Maintain Your Tomato Plants
For best results, maintain consistent care for your tomato plants. Water deeply and regularly to help roots grow strong and prevent fruits from cracking. Apply mulch around the plants to retain soil moisture and suppress weeds.
Also, provide support with stakes or cages to keep plants upright and protect the fruit from pests. Lastly, monitor for any signs of pests or diseases and address problems quickly to keep your tomatoes healthy and thriving.
10. Harvest and Enjoy!
When your tomatoes ripen, pick them at their peak for the best flavor. Depending on the variety, tomatoes may be ready when they’re fully colored and slightly soft to the touch.
Enjoy your tomatoes fresh, preserved, or cooked in your favorite recipes.
How Long Do Tomatoes Take To Grow?
Most tomato plants take 60-100 days from transplanting to produce mature fruit. The time it takes for tomatoes to grow depends on the variety. Smaller varieties, like cherry tomatoes, typically mature faster than larger ones, such as beefsteaks.
Keep in mind that factors like temperature, sunlight, and soil conditions can influence growth rates.
What Are Some Common Growing Issues for Tomato Plants?
Tomatoes can have several growing challenges. Here’s some info and solutions for how to treat the most common ones:
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Blossom End Rot: Caused by calcium deficiency and inconsistent watering. Maintain consistent soil moisture and check your soil contains sufficient calcium. Crushed eggshells are perfect for this.
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Pests: Common pests include aphids, hornworms, and whiteflies. Use natural predators, like ladybugs, or apply organic insecticidal soap to control infestations.
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Fungal Diseases: Issues like blight and powdery mildew can arise in humid conditions. Ensure proper spacing for air circulation and consider using a fungicide if needed.
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Cracked Fruit: This occurs when tomatoes receive uneven watering or rapid growth after a dry spell. Water consistently and mulch to retain soil moisture.
In general, as long as you check your tomatoes frequently and act quickly when there’s an issue, you should have the best chances of growing them to fruit.
Final Thoughts
Starting tomatoes from seed takes patience and care, but the reward of homegrown tomatoes is worth every step. Here’s a recap if you need it:
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Choose your tomato variety based on taste, purpose, and growing conditions.
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Start seeds indoors 6-8 weeks before your last frost date.
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Use seed-starting mix and keep containers warm and moist.
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Provide plenty of light as seedlings grow, and thin to the strongest plants.
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Transplant to larger pots if needed, and harden off plants before moving outdoors.
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Plant seedlings deeply in nutrient-rich soil once the weather warms.
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Maintain consistent watering, apply mulch, and support plants with stakes or cages.
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Harvest when tomatoes are fully ripe and enjoy them fresh, cooked, or preserved.
Ready to get started? Shop our tomato seed collection for a variety of high-quality, non-GMO seeds.