The most popular way to grow poinsettias is through propagation, a process in which the plant “donates” a cutting, or living piece cut off of the plant, and the cutting is given soil and water and coaxed to grow. While there are many different methods for propagation, the best one for these holiday flowers is to use a leaf cutting.
Leaf cuttings are literally just that—a cutting of a leaf. The blade and the petiole, or the leafstalk, are removed from the parent plant, and then propagated using the appropriate techniques.
You can grow one poinsettia or several with this method, and gift them to others come the next Christmas season.
Step 1 - Take Your Cuttings
The first step in taking your cuttings is knowing where to cut. For leaf cuttings, it’s recommended that you cut the whole leaf and the stem with it (that’s the petiole) by making a clean, 45-degree angle cut. You can take more than one cutting this way, but make sure that you’re not taking too much, as this can stunt or even kill the plant.
Your cutting should be about four inches long, and should be healthy and sturdy.
Step 2 - Ready Your Planter
A greenhouse planter is a big tray of little divets or holes in which to germinate and grow plants. In the case of propagating poinsettias, you can use these for the initial rooting process, and transplant them later into a terrarium that has good light, good humidity, good drainage and good moisture levels.
To ready your planter, simply add the topsoil to these divets/holes, and mist the soil with some tepid water.
Step 3 - Plant Cuttings
Now that you have your cuttings picked out and ready for planting, it’s time to plant your cuttings. First, dip your petiole into the rooting compound- just enough to coat the stem. Then gently stick it into the soil. Mist once more with the tepid water in the misting bottle and cover with the clear plastic cover that came with your little greenhouse.
Step 4 - Care For Your Cuttings
Now you need to watch your cuttings carefully. You may need to adjust the moisture level and move them to a place where they can get the warmth they need, such as the top of a refrigerator or a sunny spot. Every now and again, allow the cuttings to air out by taking the lid off of your little greenhouse and shaking the water off of it.
To prevent the leaves on your cuttings from wilting, you may have to cut them again, right down the center, but not completely through. This will increase the surface area that sunlight can hit and encourage growth. The more light you can expose your cuttings to without them wilting, the more rapidly your cuttings will root.
Keep the air temperature to about 70 degrees Fahrenheit during the day, and at about 60 degrees Fahrenheit at night. Also, keep the humidity high, as poinsettias are tropical plants and prefer humidity.
Once the cuttings have rooted and started to grow in your little greenhouse, you may (gently) transplant them to a terrarium, which looks sort of like an aquarium but is built to hold soil rather than water. Here you can control the environment of the cuttings, and get them to root better and grow bigger.
After the roots are strong and the cuttings are full plants, you can transplant them to pots and care for them just like you would with a purchased holiday flower.