Issue: July 5, 1999

New begonias and impatiens from old

I heard it was possible to save plants from the flower bed over the winter to use as houseplants and then plant outside next year. I have some beautiful impatiens and begonias. What is the best way to start new plants? What is the best time to start new houseplants?

It is a little early in most of New Mexico, but if you are thinking about it now, this is a perfect time. Starting them now will result in larger plants by the time the outdoor garden freezes. These larger plants will require more space indoors but will give you more flowers in the fall and early winter. Whether or not you have flowers later depends on the light intensity and cultural conditions inside.

These plants that you mentioned are quite easy to start from cuttings. Just remove a three- to four-inch piece of the end of one of the stems,then carefully break the leaves from the bottom two-thirds of the plant or trim them off with a sharp knife.

These prepared cuttings may be rooted in water or in good, sterile (pasteurized) potting soil. To root them in water, just place them in water up to the point just below the remaining leaves. For this you may use a vase, a drinking glass, or an old jelly jar. As the water evaporates, refill the container. Once every week or so, replace the water so that the mineral salt in the water doesn't accumulate as the water evaporates. This is especially important because of the hardness of most of our New Mexico water sources. DO NOT use water from water softeners, which replace the hard water minerals with other minerals that may be even more toxic to the plants. Once roots have formed and are beginning to grow you may place the rooted cuttings in a pot with good potting soil, or for fun you can leave them in the water container.

Until the roots have formed, there is no need to add fertilizer. However, once the roots form you can begin fertilizing with a diluted flowering houseplant fertilizer. This is true whether you are growing them in soil or in water. Wait a week of so for the roots to establish in the soil before fertilizing. This fertilizer is necessary for the vigorous growth of these new plants in the confined root environment in which you are maintaining them.

You may also place the prepared cuttings directly into the sterile potting soil. For these plants, use of a root-stimulating hormone powder is not necessary, but it does speed the formation of the roots. For difficult-to-root cuttings, the root hormone powders will not be optional. These powders are not useful if you root the cuttings in water.

Dip the cut end of the prepared cutting into the rooting powder, then gently tap off any excess powder. Carefully insert the cutting into preexisting holes in the potting soil. The preexistence of the holes is necessary so that the rooting powder isn't rubbed off. In a couple of weeks new roots should have formed on your new house plants. As described with the water-rooted cuttings, you may then begin fertilizing with a diluted flowering houseplant fertilizer.

Place the plants in a well-lighted location. Group plants together so that the humidity in the vicinity will be increased. Under good conditions, they should begin blooming in a month or so and continue through the winter. In the late winter you may again begin taking cuttings to produce new plants for use outside. Also consider buying new plants so that you may get new colors of flowers for your landscape and for your interiorscape as you make cuttings next autumn.