Yes, you can grow tomatoes from a tomato, but the seeds need preparation first
You can grow a tomato plant from seeds taken directly out of a fresh tomato, but not by planting the tomato whole or by planting the seeds exactly as they come out. The seeds inside a tomato are coated in a gel-like substance that prevents them from sprouting — this coating exists in nature to stop seeds from germinating inside the fruit while it's still on the plant. You have to remove that coating, dry the seeds, and then plant them in soil under the right conditions. It takes about six to eight weeks from seed to a plant large enough to move into a garden.
Key Takeaways
- Seeds from a tomato are covered in a germination-blocking gel that must be removed by fermentation or washing before they will sprout.
- Fermentation — soaking seeds in water for two to three days until they smell sour — is the fastest and most reliable method to clean seeds at home.
- Seeds must be dried completely on a paper towel or plate before storage or planting, which takes three to five days in a warm, dry spot.
- Cleaned, dried seeds will sprout indoors under grow lights or a sunny window in soil kept moist but not waterlogged, with germination in seven to fourteen days.
- Seedlings need to be thinned or transplanted into individual pots once they develop their first true leaves, about three to four weeks after sprouting.
How to remove the seed coating by fermentation
Fermentation is the method most home gardeners use because it works reliably and requires nothing but a jar and water. Scoop the seeds and gel out of a ripe tomato into a small jar or cup. Add just enough water to cover the seeds — about a quarter cup for seeds from one tomato. Leave the jar uncovered on a counter at room temperature.
After two to three days, the seeds will sink to the bottom and the gel will break down into a cloudy, sour-smelling liquid. This smell is normal and means the fermentation is working. Rinse the seeds thoroughly under running water, rubbing them gently between your fingers to remove any remaining gel. A fine-mesh strainer makes this easier. Once the seeds feel clean and slippery gel is gone, spread them on a paper towel to dry.
Drying seeds so they stay viable
Wet seeds will rot before they sprout, so drying is essential. Spread the cleaned seeds in a single layer on a paper towel, coffee filter, or ceramic plate — not plastic, which can trap moisture. Place them in a warm, dry location out of direct sunlight: a kitchen counter, shelf, or closet works well. Air circulation helps, so avoid sealed containers.
Seeds are fully dry when they feel papery and break cleanly if you bend them — this usually takes three to five days depending on humidity in your home. Once dry, store them in a paper envelope in a cool, dark place until you are ready to plant. Dried tomato seeds stay viable for four to five years if kept dry and cool.
Planting seeds indoors under lights or in a window
Start seeds indoors six to eight weeks before your last spring frost date. Fill a seed tray, small pots, or recycled containers with seed-starting mix — a light, sterile soil blend that drains well and does not compact. Moisten the soil before planting. Plant seeds about a quarter inch deep, two or three seeds per cell or pot in case some do not sprout.
Cover the tray loosely with a plastic dome or plastic wrap to hold moisture, and place it under grow lights set to run fourteen hours a day, or on a south-facing windowsill. Keep soil moist but not soggy — overwatering causes damping off, a fungal disease that kills seedlings at the soil line. Seeds will sprout in seven to fourteen days. Once sprouts appear, remove the cover and may support lights are two to three inches above the seedlings to prevent them from becoming leggy and weak.
Thinning seedlings and moving them to larger pots
When seedlings develop their first true leaves — the second set of leaves that look like actual tomato leaves, not the smooth seed leaves — thin them to one plant per cell. Pinch off the weaker seedlings at soil level rather than pulling them out, which can disturb the roots of the keeper plant. If you planted one seed per pot, skip this step.
At four to six weeks old, seedlings are ready to move into larger individual pots, usually four inches across. Bury the stem up to the lowest leaves — tomato roots will form all along the buried stem, creating a stronger root system. Continue grow lights or bright window light, and keep soil consistently moist. Feed seedlings with a diluted liquid fertilizer every two weeks once they have four true leaves.
Hardening off before moving plants outside
About two weeks before your last frost date, begin hardening off seedlings by exposing them gradually to outdoor conditions. Start with one hour in a sheltered, shaded spot, then increase time and light exposure over seven to ten days. This toughens the plants so they do not wilt or sunburn when planted in the garden.
Transplant seedlings into the garden after all frost danger has passed and soil has warmed to at least 60 degrees Fahrenheit. Space plants two to three feet apart in full sun with rich, well-draining soil. Bury the stem deep again, leaving only the top leaves above soil. Water deeply after planting and keep soil consistently moist for the first two weeks while roots establish.
Why seeds from store-bought tomatoes often do not work
Most tomatoes sold in grocery stores are hybrid varieties, meaning seeds saved from them will not grow plants identical to the parent. The fruit may be smaller, less flavorful, or a different color than the tomato you took seeds from. If you want seeds that grow true to type, save seeds from heirloom or open-pollinated varieties, which you can find at farmers markets, seed catalogs, or specialty produce shops.
Hybrid seeds also have lower germination rates than seeds from heirloom varieties, so you may need to plant more seeds to get the same number of plants. If you want reliable results, buying seed packets from a seed company is more cost-effective than trying to save seeds from grocery store tomatoes.
Frequently Asked Questions
Can I plant tomato seeds directly in the garden instead of starting them indoors?
Yes, but only if your growing season is long enough. Direct-seeding tomatoes in the garden takes about twelve to fourteen weeks from seed to first fruit, which works only in regions with frost-free periods of four months or longer. Starting seeds indoors gives you a head start and lets you harvest fruit earlier in the season.
What if my seeds do not sprout after two weeks?
Check that soil is moist, not waterlogged, and that lights are on fourteen hours daily. Tomato seeds need warmth to sprout — soil temperature should be between 70 and 80 degrees Fahrenheit. If your home is cold, place the seed tray on a heat mat. If seeds are still dormant after three weeks, they may not be viable; discard them and start fresh.
Do I need grow lights, or will a window work?
A bright south-facing window works if you have one, but seedlings often become leggy and weak reaching toward light. Grow lights are inexpensive and produce stronger, stockier plants. Even a basic LED shop light from a hardware store, positioned two to three inches above seedlings, will outperform a window.
How do I know when seedlings are ready to plant outside?
Seedlings are ready when they are six to eight inches tall, have at least four true leaves, and have been hardened off for seven to ten days. They should look sturdy and green, not pale or spindly. If they are still small at two weeks before your last frost date, start hardening them off anyway — they will continue growing outdoors.
Can I save seeds from the tomatoes my plants produce?
Yes, if you grew them from heirloom or open-pollinated seeds. Hybrid tomatoes will not produce seeds that grow true to type. Ferment and dry seeds from your best-tasting, healthiest fruits the same way you prepared the original seeds, and store them dry and cool for next season.