Cloning a tomato plant propagates an identical copy of the parent plant. If you have a tomato plant in your garden that produces particularly delicious fruit or has shown a strong disease resistance, clone the plant to produce a full garden of the prize tomato plant. Cloning also allows gardeners to share their best tomato plants with fellow gardeners with little effort.
Step 1 - Select a Plant to Clone
Clone only disease-free tomato plants. Candidates for cloning include tomato vines that are exceptionally prolific producers or that produce tomatoes with a particularly desirable fruit. Gardeners may also clone hybrid plants for which they no longer have seeds, since the daughter plants will come true to the parent plant, unlike saving seeds from hybrids.
Step 2 - Take a Cutting
Cut a six-inch length of tomato stem to make the clone. The cutting can be from a sucker, the branches that grow between the main stem and primary branches, or from a growing tip. Many gardeners prefer cloning tomatoes from the suckers, since removing suckers doesn’t affect the mature size of the mother plant. Keep the cutting wrapped in moist paper toweling until it is rooted.
Step 3 - Prepare the Cloning Medium
Fill a pot at least four-inches deep with the growing medium. Tomato clones root well in vermiculite, sterile seed-starting medium, peat-sand mixtures, or standard potting mix. Ensure that the growth medium is moist. Use a pencil or dibble to create a four-inch hole in the medium. Plain water also works as a cloning medium for tomato plants.
Fill a glass with clean, filtered water to root the cutting in. Tomatoes cloned this way may need some time to adjust when moved to soil, since the roots they grow initially aren’t adapted for taking up soil nutrients.
Step 4 - Root the Cutting
Remove all flower buds and all but the top two leaves from the cutting. Insert the stem of the cutting at least four inches into the prepared growth medium, and press the medium firmly around the stem. Powdered rooting hormone on the stem may encourage the cutting to develop roots. However, tomatoes root so readily from their stems that rooting hormone is not necessary. When using plain water as a growth medium, suspend the stem so it doesn’t touch the bottom or sides of the glass.
Step 5 - Let Roots Establish
Roots establish on cloned tomato cuttings within a few weeks.
Keep the cuttings moist but not soggy, and place in partial shade while they put out roots. After two weeks, check the progress of root development by gently pulling up on the cutting stem. As the roots establish, the cutting will stay firmly in the medium.
Once tomatoes cloned in water have developed significant root structures, transplant as you would a bare-root plant into a six-inch pot of good quality potting mix.
Step 6 - Transplant the Cloned Tomato
When the cloned tomato has established a good root structure in the soil and the main stem is at least the diameter of a pencil, the cloned tomato plant is ready to be transplanted into the garden or a permanent container.