Tomato suckers are shoots you can root in water and plant as new tomato plants
A tomato sucker is a side shoot that grows between the main stem and a branch on a tomato plant. Instead of removing every sucker, you can cut them off, root them in water, and plant them in soil to grow new tomato plants. This method works because tomato suckers develop their own root systems quickly — usually within one to two weeks in water — and grow into mature plants that produce fruit the same way a plant grown from seed does.
The main advantage is speed: a rooted sucker planted in spring will reach full size and start flowering by mid-summer, whereas a seed-grown plant takes eight to ten weeks just to reach transplant size. You also know exactly what you are growing, since the new plant is a clone of the parent plant. The downside is that you need a healthy parent plant to take suckers from, and you can only grow as many new plants as the parent can spare without losing too much foliage.
Key Takeaways
- Cut tomato suckers from a healthy plant when they are three to six inches long, using a clean knife or pruners to avoid crushing the stem.
- Place the cut sucker in a glass of water in a warm, bright location and change the water every two to three days until roots appear, which usually takes one to two weeks.
- Once roots are one-quarter inch long or longer, plant the sucker in moist potting soil in a small pot and keep it in indirect light for the first few days.
- Harden off the rooted sucker by gradually exposing it to outdoor conditions over seven to ten days before planting it in the garden.
- Take suckers only from the lower half of the plant so you do not remove too much foliage and weaken the parent plant's ability to produce fruit.
When and where to cut tomato suckers
The best time to take suckers is when the parent plant is actively growing and healthy — usually from late spring through mid-summer. At this point the plant has enough foliage to spare a few shoots without losing its ability to photosynthesize and produce fruit. Avoid taking suckers from a plant that is stressed by drought, disease, or extreme heat, because the parent plant will not recover as quickly.
Look for suckers in the crotch between the main stem and the first set of true leaves, or between the main stem and any branch. The lower half of the plant is the best place to take from, since removing suckers from the top can stunt the plant's height and reduce flowering. Cut suckers that are three to six inches long — they are large enough to handle but still tender enough to root quickly. Use a clean knife or pruning shears to make a single cut just below a leaf node (the small bump where leaves attach to the stem). Do not tear or crush the stem, because damage slows rooting.
Rooting tomato suckers in water
Fill a glass or jar with room-temperature water and place the cut sucker in it so that the bottom one to two inches are submerged. Set the glass in a warm spot with bright, indirect light — a windowsill that does not get direct afternoon sun is ideal. The sucker does not need soil or rooting hormone to develop roots, though some gardeners add a small amount of rooting powder to speed the process slightly.
Change the water every two to three days to keep it oxygenated and prevent bacterial growth. Within one to two weeks, you should see small white roots emerging from the base of the stem. Once the roots are at least one-quarter inch long, the sucker is ready to plant in soil. If you wait much longer, the roots become fragile and are more likely to break during planting. If roots have not appeared after three weeks, discard the sucker and try another one — it may have been damaged during cutting or the parent plant may not have been healthy enough to root.
Planting rooted suckers in soil
Use a small pot — four to six inches across — filled with moist potting soil or seed-starting mix. Make a hole in the soil with your finger and gently place the rooted sucker into it, burying the stem up to the lowest leaf. Tomato stems can develop roots all along their length, so burying part of the stem encourages a stronger root system. Pat the soil gently around the stem so it stands upright and the roots make contact with the soil.
Water the soil lightly and place the pot in a warm location with bright, indirect light for the first three to five days. This reduces transplant shock and gives the roots time to adjust to soil before the plant faces direct sun. After that, move the pot to a sunny windowsill or grow light where it will receive at least six to eight hours of light per day. Keep the soil moist but not waterlogged — the top half-inch should dry slightly between waterings. Within one to two weeks, you should see new leaf growth, which means the roots have established and the plant is growing.
Hardening off before planting in the garden
A rooted sucker grown indoors is tender and will wilt or stop growing if planted directly into the garden. Instead, spend seven to ten days gradually exposing it to outdoor conditions — a process called hardening off. Start by placing the pot outside in a sheltered, shaded spot for one to two hours on the first day. Each day, increase the time outdoors and gradually move the pot into brighter light, until by day seven or eight it is spending the full day in direct sun and outdoor temperatures.
Watch the soil moisture closely during hardening off, because outdoor air dries pots faster than indoor air. Water as needed to keep the soil moist. If the plant wilts during the day, move it back to shade for a day and try again more slowly. Once the plant has spent two full days in direct sun and outdoor conditions without wilting, it is ready to plant in the garden bed.
Planting in the garden and ongoing care
Choose a spot in the garden that receives at least six to eight hours of direct sun per day. Dig a hole slightly larger than the pot and gently remove the sucker from its pot, keeping the soil around the roots intact. Plant it at the same depth it was growing in the pot, or slightly deeper — burying part of the stem encourages more roots to form. Space plants two to three feet apart to allow air circulation and reduce disease.
Water the newly planted sucker deeply and keep the soil consistently moist for the first two weeks while it establishes. After that, water when the top inch of soil is dry. Stake or cage the plant as it grows, and pinch off any new suckers that form on the main stem if you want to focus the plant's energy on fruit production rather than growth. The plant should begin flowering within four to six weeks and produce ripe fruit by mid to late summer.
Frequently Asked Questions
Can I root tomato suckers in soil instead of water?
Yes, though water rooting is faster and easier to monitor. If you root in soil, use a small pot of moist potting mix, bury the bottom inch of the sucker, cover the pot loosely with a plastic bag to keep humidity high, and keep the soil moist. Roots usually form in two to three weeks, but the sucker is more likely to rot if the soil stays too wet.
How many suckers can I take from one plant without harming it?
Take no more than two or three suckers from a healthy plant, and only from the lower half of the stem. Removing too many suckers weakens the plant and reduces fruit production. If the plant is small or stressed, take only one sucker and wait a few weeks before taking another.
Do I need rooting hormone to root tomato suckers?
No, tomato suckers root easily in plain water without any rooting hormone. Some gardeners add a small amount of rooting powder to speed rooting slightly, but it is not necessary. If you use rooting hormone, follow the package directions and use only a light dusting on the cut end.
What if my rooted sucker gets leggy or pale indoors?
This means the plant is not getting enough light. Move it closer to a sunny window or place it under a grow light positioned four to six inches above the plant. Leggy plants will still grow and produce fruit, but they are weaker and more prone to disease. Increasing light will slow the legginess and encourage stronger growth.
Can I take suckers from a determinate tomato plant?
Yes, but determinate plants (bush types that grow to a fixed size and fruit all at once) produce fewer suckers than indeterminate plants (vining types that grow all season). You can still root and grow them the same way, but you will have fewer new plants to work with from a determinate parent plant.