Each plant has its own characteristics as to how it puts out roots. But there are some general guidelines for most houseplants, tropicals and some trees.
Every technique starts with good water; filtered tap water or fresh rainwater.
- Oxygen: Roots need oxygen to thrive. The more water sits idle, the less aerated it is. Keeping the water moving keeps it saturated with oxygen.
- Heat: Warmer roots form faster, but keep heat directed to the roots to limit the need for the cutting to transpire valuable moisture.
- Light: Do not subject tender plants to high light levels.
- Fertilizer: It is important to include phosphorus for root growth. Use a water soluble or liquid fertilizer at no more than ¼ recommended levels. This will reduce transplant stress.
- Sterilization: Diseases or other pathogens can be a problem. Simple sterilization can be achieved with boiling water, or bleach if necessary. Glass is a good option for reusable containers that can stand up to repeated cleanings.
The Bubbler
This technique is a cheap and easy way to increase survivability rates. Make bubbles in the water by using an aquarium air pump. More vigorous bubbles means more oxygen. An air stone helps limit heavy vibrations, but is not necessary. The air will maintain humidity if it is kept within an enclosed area. This will also limit evaporation, pests and pathogens. Place the cutting through a hole in a lid or a flat piece of Styrofoam which floats on the surface. A drink bottle with a narrow neck can hold the air hose and plant together.
Modified Bubbler
This technique is based on a bubbler system that is made semi-aeroponic. While the air pump is off, set the very bottom of the clone about a half-inch above water level. Bubble vigorously and the water will splash onto the clone and fall off or bubbles will burst on the cutting and help it remain moist.
Potato Graft
This technique works well with woody stems. The idea here is to use the potato as a grafted root. Put a cut or hole in the potato so that your clone will fit snugly inside. “Plant” your cutting in the potato and then bury the potato in soil just below the surface. The potato will quickly grow roots while providing the plant with its required moisture and nutrients. As roots from the clone develop, the soft potato will give way and split. Potato leaves will also develop and should be removed.
Humidity Dome
Besides oxygen for the roots, creating a warm, humid environment is the best way to increase a cutting’s survival rate. A humidifier can raise the moisture of an entire room. Keeping the clone in the bathroom can sometimes be the best option if the light is adequate. For small cuttings, a plastic grocery bag can be placed in a dome shape over it. Bags that allow filtered light are idea. You can make a dome with some small wire or a metal coat hanger. Even more humidity can be introduced by misting inside. Mold will form easily in this environment so replace the bag often.
Rooting Hormones
Some trees create their own rooting hormones and can be used in place of commercial products. As long as pathogens are not a concern, take a living branch from a willow tree and place it in the water you plan to use for rooting another plant for at least one day. This tree cutting will continue to produce the hormone and can be soaked for weeks in a separate container. Use a little at a time while watering the clone and refill the container with fresh water as needed.
While nothing can guarantee 100 percent survivability, any one or a combination of these techniques will increase the chances of your rare and valuable clones developing the necessary root system to thrive.
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