How to Clone a Tomato Plant

Choose an offshoot, or sucker, from the junction between
the main stem and a larger branch of your tomato plant.
Photo by Brad Sylvester
All rights reserved

When most people think of cloning, they think laboratories, bio-hazards and maybe even one of the Star Wars movie sequels. In reality, cloning your favorite tomato plants is quick and easy. It's a great way to propagate tomato plants and jump start your winter indoor garden.

Because clones are genetically identical to the original, they should share all the properties of the parent plant. This method is great for propagating hybrid varieties that don't breed true from second-generation seeds.

Just keep one plant inside over winter and use it to create the next spring's plantings. It's also a great way to save money. If you buy one large potted tomato plant from a local vendor, you can clone it and get extra plants for free! This is a great trick for expensive heirloom varieties.

To promote a vigorous and healthy tomato plant, you should remove the suckers (especially from the bottom 1-2 feet of the plant) as these will divert energy away from the main producing stems and lower your overall yield if left in place. Removing the suckers also keeps the tomato from getting too thick and bushy near the ground. Good airflow around the base of your plant helps to prevent mold, fungus, and diseases from getting a foothold in your garden.

First make sure the tomato plant you're using is healthy with no signs of blight or other disease. Using contaminated plants for this will just propagate the disease and the new plants will not be successful.

Then look for the places where a large branch comes off the main stem. Many of these will have a new smaller branch growing from the "V" formed by the stem and the branch. These are called suckers. These suckers are what we're after. In the picture below, the small stem in the center is the sucker. They will grow and add new leaves, whereas the other established branches will not. Look at the other branches and notice how there is no place on them where new leaves are growing. These branches are just food factories for the rest of the plant. The suckers are like brand new complete tomato plants and will add new leaves, flower, and bear fruit. They should snap off easily if you gently bend them at their base. Be careful not to squeeze the stems as this can damage them and kill the suckers.

You can plant each sucker in an individual pot or put several into a planter box or window box. Space them at least 3"-4" apart if you use a common planter. If you use an individual pot, choose one that is at least 3-4" deep to allow room for good root development. And bear in mind that you may need to transplant to a larger container later if they get too big before it's time for them to go outside into your regular garden. I use Miracle Gro's Moisture Control Potting Soil. It is the right consistency, doesn't pack down hard, holds moisture well, and feeds the plants for the first three months in the new soil. This helps them grow faster and more reliably as they establish new root systems. Using a pencil or similar implement, poke a hole into the soil.

You'll want to plant the sucker as deeply as possible keeping leaves and branches about an inch above the top of the soil. If you need more depth, you may need break or trim the bottom-most pair of leaves off the sucker before placing it into the hole. Gently firm up the soil around the newly planted sucker. You want to make sure you don't leave any air pockets around the stem.

Water the new plant generously and keep an eye on it for the next few days. For the first few days, you will see it wilting from time to time. Remember it has no roots at all and needs to re-establish an entire root system. For the first week, it should be kept out of direct sun, but still in a bright place. When you see it wilting, you can give it a boost with a light leaf misting to help the plant absorb water. It will most likely wilt every day for 3-4 days until some new roots begin to form. Keep the soil very moist for 3-4 days, then water as you would a normal tomato plant.

After about a week, your plant should have enough roots to keep it going with no special treatment, place it in the sun and keep it well watered. If they do start to wilt, continue to mist them. I'd wait at least 3-4 weeks before transplanting to their permanent location (longer is ok). Then, just take care of it like any normal tomato. Remember tomato plants love the sun! Once it is established it should be given as much light as you can give it during the day, but don't be tempted to leave indoor grow lights on 24 hours a day. Plants need the day night cycle for proper growth and maturation. 12-14 hours of light per day works great for tomatoes.

Not every cloned plant will make it past the first week, but if you follow these steps, you should have a very high rate of success. With good follow up care, you'll have a healthy new crop of cloned tomato plants. You can increase your rate of success by applying a Rooting Hormone to the suckers before placing them in the soil. There are many different brands available and they can be found online or at your local nursery. Follow the directions for the one you buy. Basically, though, all you need to do is dip the portion of the sucker that will be in the dirt into the rooting compound before planting it. If the rooting compound you choose is a powder then just dip the sucker in water first to help the powder adhere to the plant. With a rooting compound, you should get nearly one hundred percent success in cloning tomatoes.