Issue: Septe1ber 29, 2001

Little crystals on ficus leaf

I have a ficus tree inside my house. It is growing rapidly and looks good. However, I noticed some little crystals at the base of almost all the leaf blades. These crystals are in the same location on each leaf. Is there something wrong?

It is possible that there is a small insect present causing this problem. However, the fact that all the crystals are in the same location at the base of the leaf blade in so many of the leaves suggests another answer. A rapidly growing tropical plant will often have a large quantity of water containing nutrients and sugar in its vascular tissues. At night when evaporation is less, some of this water is exuded from specialized locations on the leaf blade. As the water evaporates, the sugar and other material in the water remains behind and crystalizes. I suspect that this is the answer in the case of your ficus.

Time to bring in Christmas cacti?

Is it time for me to bring my Christmas cactus indoors? When do I begin putting it into the closet at night to make it flower? -Amy A. (Albuquerque)

You should bring your Christmas cactus indoors before freezing kill it. As the temperatures drop into the 40's at night or when the weather forecast predicts temperatures in the 40's, bring them indoors. If you wish, you may return them to their outdoors location during the day, but don't forget to bring them in on cold nights. The Christmas cacti are from the high mountains of the American tropics, so they can tolerate some cool weather, but they are also killed by freezing temperatures.

Regarding the time to begin inducing flowering by providing long night conditions: Now that the autumnal equinox (first day of fall) is past, we can begin treating the Christmas cacti, poinsettias, and kalanchoes with long periods of uninterrupted darkness each night. Remember to return them to the light during the day. You can do this by placing them in a cool closet each night, or leave them in an unused room in which the lights will not be used at night. You may also cover them with a black garbage bag or other dark material each evening at or before sunset if they are in a room in which the lights will be used.

Room temperatures at or below 60 degrees Fahrenheit enhance flower development. Don't let temperatures drop below 40 degrees. Be sure the plants are watered, but not as much as during their growing season. Let the soil dry between waterings. Do not apply no nitrogen fertilizer during the period of flower induction. Once the flower buds appear, don't move the plants any more than necessary. Changes in location will cause the Christmas cacti flower buds to drop from the plants.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms and the NMSU Horticulture Publications page.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!