The Easiest Way to Root Calibrachoa Cuttings

Preparing the Containers

• To root Calibrachoa cuttings, you need 4-inch diameter plastic containers and a tray to hold them. The proper rooting medium is one part perlite mixed with three parts well-draining potting mix. Moisten the mixture evenly before filling the containers to the top. Do not compact the mix in the pots, as it needs to be airy for the roots to grow, and it will naturally settle with watering.

Gathering and Preparing the Cuttings

• Calibrachoa has wirelike, thin stems, so use small clippers to snip 3- to 4-inch tip cuttings from a healthy plant. You must remove the leaves from the bottom inch of the cutting before dipping the cut ends into liquid or powder rooting hormone. Stick three cuttings into each 4-inch pot in a triangle, approximately 1 inch apart.

Temperature, Bottom Heat and Light

• Calibrachoa cuttings need a constant air temperature of 70 degrees Fahrenheit and bottom heat to root successfully. A heating mat placed under the tray is the best way to provide bottom heat. Never use a heating pad not suited for horticultural use for bottom heat because of the risk of shock from water and humidity. Horticultural heating mats are waterproof. To avoid stretching, the cuttings must be placed in very bright light.

Humidity and Watering

• The cuttings will need constant humidity to prevent wilting. Keep the soil moist but not wet. To provide humidity, an enclosed environment, such as a portable plastic greenhouse, is ideal, but placing a plastic bag upside-down over each pot works well. Don't place the pots into plastic bags and close the tops because they may rot. Remove the bag for around five minutes daily to provide air circulation and mist the cuttings. Be careful not to mist too heavily.

Fertilization and Finishing

• Roots usually appear within seven to 14 days, but slower-rooting varieties may take up to 21 days to root. Remove the heating mat and the plastic bags once roots are visible, but maintain the same air temperature. Begin fertilizing your Calibrachoa cuttings weekly with a one-quarter strength solution of a balanced 20-20-20 fertilizer containing minor elements. Once you begin fertilizing, pinch or snip out the top few leaves of the plant to encourage branching.

Considerations

• If the cuttings begin to stretch before they are rooted, you may snip or pinch out the top few leaves. Be careful not to disturb the cutting, as this could cause it not to root. In warm, humid, subtropical climates, Calibrachoa cuttings can be rooted outside in semi-shade in the spring and fall when nighttime temperatures are 70 degrees Fahrenheit and daytime temperatures are not above 80 degrees Fahrenheit.