You can propagate tomatoes two ways: from cuttings taken from a living plant, or from seeds saved from ripe fruit

Propagation from cuttings is faster — you get a mature plant that flowers within weeks. Propagation from seed takes longer but gives you more plants from a single fruit, and the seedlings are often hardier. Cuttings are clones of the parent plant, so they produce identical fruit. Seeds from hybrid tomatoes may not grow true to type, meaning the fruit could taste or look different from the original.

Both methods work indoors or outdoors, depending on your climate and season. Cuttings root best in spring and early summer when the parent plant is actively growing. Seeds can be started indoors 6 to 8 weeks before your last frost date, or directly in the garden once soil warms.

Key Takeaways

  • Cuttings root in water or soil within 7 to 14 days and produce a flowering plant in 4 to 6 weeks, while seeds take 6 to 8 weeks to reach transplant size.
  • Use a clean, sharp knife to cut 4- to 6-inch stems just below a leaf node, remove the lower leaves, and place the cutting in water or moist soil indoors.
  • Seeds need warmth (70 to 80 degrees Fahrenheit), moisture, and light once they sprout, and should be thinned or transplanted when the first true leaves appear.
  • Cuttings taken from determinate (bush) varieties stay compact, while cuttings from indeterminate (vining) varieties grow tall and need staking or caging.
  • Harden off seedlings and rooted cuttings by gradually exposing them to outdoor sun and wind for 7 to 10 days before planting in the garden.

Propagating from cuttings in water

Cut a healthy stem 4 to 6 inches long from the parent plant, using a clean knife or pruners. Make the cut just below a leaf node — the small bump on the stem where leaves branch off. Nodes contain the cells that form roots, so cutting there speeds rooting.

Remove all leaves from the bottom 2 inches of the cutting. Leave the top leaves intact — they feed the cutting while roots develop. Place the cutting in a glass or jar of room-temperature water, making sure the bottom inch is submerged but no leaves touch the water (wet leaves rot). Change the water every 2 to 3 days to prevent bacterial growth.

Roots usually appear within 7 to 14 days. Once roots are at least 1 inch long, transplant the cutting into a small pot filled with moist potting soil. Keep the soil consistently moist for the first week, then water when the top inch feels dry. Place the pot in bright, indirect light — a sunny windowsill works well.

Propagating from cuttings in soil

If you prefer to skip the water stage, you can root cuttings directly in soil. Prepare a small pot with moist potting mix or a mix of equal parts peat moss and perlite. Make a hole in the soil with your finger or a pencil, insert the cutting so the bottom 2 inches are buried, and gently firm the soil around it.

Cover the pot loosely with a clear plastic bag or dome to hold humidity — this speeds rooting. Place it in bright, indirect light at room temperature. Check the soil every few days and mist it if the top feels dry, but do not overwater. Remove the cover once new growth appears at the top, which signals that roots have formed.

Soil rooting takes slightly longer than water rooting — usually 14 to 21 days — but the cutting avoids the shock of moving from water to soil, so it may establish faster once transplanted to a larger pot.

Starting tomatoes from seed indoors

Fill a seed tray or small pots with seed-starting mix, which is lighter and drains better than potting soil. Moisten the mix before planting. Plant seeds about 1/4 inch deep, spacing them 1 inch apart. Cover the tray with a humidity dome or plastic wrap.

Place the tray in a warm spot — 70 to 80 degrees Fahrenheit is ideal. A heat mat under the tray speeds germination. Seeds sprout in 5 to 10 days. Once sprouts appear, remove the cover and move the tray to bright light when ready — a grow light 2 to 3 inches above the seedlings works better than a windowsill, which often produces leggy, weak plants.

Water from below by setting the tray in a shallow pan of water for 10 minutes, then removing it. This keeps the soil moist without wetting the leaves. Once seedlings have two true leaves (the second set to appear, which look like tomato leaves), thin them by removing weaker seedlings or transplant each one into its own small pot. Bury the stem up to the first true leaves — tomatoes root along buried stems and develop stronger plants this way.

Caring for seedlings and rooted cuttings before planting

Both seedlings and rooted cuttings need bright light, consistent moisture, and air circulation. If growing under lights, keep them on for 14 to 16 hours daily. If using a windowsill, rotate the pots every few days so they grow straight instead of leaning toward the light.

Water when the top of the soil feels dry, but do not let the soil stay soggy — wet soil causes damping off, a fungal disease that kills seedlings at the soil line. A small fan on low speed pointed at the plants (not directly on them) improves air circulation and prevents this problem.

Once seedlings are 2 to 3 inches tall, you can feed them weekly with a diluted liquid fertilizer made for seedlings, which is lower in nitrogen than regular plant food. Stop feeding once you move them outdoors.

Hardening off before transplanting to the garden

Seedlings and rooted cuttings grown indoors are tender and sunburn easily if moved directly outside. Harden them off by gradually exposing them to outdoor conditions over 7 to 10 days. Start by placing them in a shaded, sheltered spot outdoors for 1 to 2 hours, then bring them back inside. Each day, increase the time outside and the amount of direct sun they receive.

By day 7 or 8, they should tolerate full sun and outdoor wind for the whole day. Leave them outside overnight once nighttime temperatures stay above 50 degrees Fahrenheit. After hardening off, the plants are ready to transplant into the garden.

Planting rooted cuttings and seedlings in the garden

Wait until nighttime temperatures stay above 50 degrees and soil has warmed to at least 60 degrees — tomatoes planted in cold soil often sit dormant or rot. Dig a hole slightly larger than the root ball, and plant the seedling or rooted cutting at the same depth it was growing in its pot, or slightly deeper. Bury the stem of a leggy seedling up to its first true leaves to encourage a stronger root system.

Space determinate (bush) varieties 24 to 36 inches apart and indeterminate (vining) varieties 36 to 48 inches apart. Water thoroughly after planting, and keep the soil consistently moist for the first 2 to 3 weeks while the plant establishes. Once it is growing steadily, you can reduce watering frequency — tomatoes prefer soil that dries slightly between waterings.

Frequently Asked Questions

Can I propagate a tomato plant in winter?

Cuttings root more slowly in winter because the parent plant grows less vigorously and indoor light is weaker. If you take cuttings indoors under grow lights, they will root, but it may take 3 to 4 weeks instead of 1 to 2. Seeds started indoors in winter work fine as long as you provide 14 to 16 hours of bright light daily.

What if my cutting turns yellow or wilts?

Yellowing usually means the cutting is rotting from too much moisture or bacteria in the water. Change the water when ready, trim off any mushy parts, and use fresh water. Wilting often means the cutting lost water faster than roots could replace it — mist the leaves daily and keep the air humid until roots form. If the cutting is still firm, it will usually recover.

Do I need to use rooting hormone?

Rooting hormone speeds rooting by a few days and increases success rate, especially for woody or older stems. For soft, young tomato stems, it is not necessary — they root easily in water or moist soil without it. If you use it, follow the package directions and use only a small amount, as too much can burn the cutting.

Can I save seeds from store-bought tomatoes?

Yes, but only from heirloom or open-pollinated varieties. Hybrid tomatoes (often labeled F1) produce seeds that grow into plants with different fruit — sometimes smaller, less flavorful, or a different color. Scoop seeds into a jar with a little water, let them ferment for 2 to 3 days to remove the gel coating, rinse them, and dry them on a paper towel before storing.

How long does it take to get fruit from a propagated plant?

A rooted cutting usually flowers within 4 to 6 weeks and produces ripe fruit 6 to 8 weeks after that, so you can harvest within 2 to 3 months. A seedling takes longer — 8 to 10 weeks to reach flowering size, then another 6 to 8 weeks to fruit, so plan on 4 to 5 months from seed to harvest.