ASK THE GARDENERS. Questions & Answers

Q In October, a friend gave me what she said was a Christmas cactus. However, it soon formed buds and started blooming Nov. 1. I put it in a bright window, but out of direct sun, and have kept it just moist. My friend cautioned me not to water it too much or it might rot off. When it finishes blooming, how do I care for it? Is it true Christmas cactus?

S.N.

Redding, Calif.

Previously, folks could tell the difference between Christmas cactus (Schlumbergera bridgesii) and Thanksgiving cactus (S. truncata), also called crab cactus, by looking at the stem segments.

Thanksgiving cactus has hooklike structures on the segments, while true Christmas cactus has smooth, rounded stem segments.

Cross-pollination of the different species has given us plants with varying stem segments and a variety of colors and bloom sizes. You probably have one of these new hybrids with a different ``time clock.''

You are caring for it properly. It is helpful to give it liquid feeding about every six weeks during blooming and during its spring and summer growth period. We summer ours outdoors, next to our house foundation, with indirect light, bringing it indoors just before frost.

Cool late summer and early fall nights induce buds to form. Plants can be kept indoors all year, and will bloom if they are kept at 50 degrees to 55 degrees F. at night from early September to late October.

Folks who can't keep their plants below 60 degrees F. at night can give them 13 hours of complete darkness every night during this period and get blooms by holiday time. Q We have just decided to build a lean-to greenhouse onto the side of our house. We have chosen an attractive plan and feel we will be able to grow many flowering plants in winter.

The man who installed our home heating unit (gas hot water) says he can run a line from the house, and the same boiler will be adequate for the greenhouse if we can keep the thermostat at 55 degrees F.

We would like to know if this is feasible, and what plants would tolerate this temperature during winter.

E.R.S.

Athens, Ohio

When the thermostat is set at 55 degrees F., that means the temperature will not fall below 55 degrees F. at night. During the daytime, the sun, even on cloudy days, will raise the temperature.

There are a great many flowering plants you can grow, either in pots or right in a bench. Here are some of them: calendulas, carnations (Dianthus), snapdragons, flowering bulbs, geraniums, nasturtiums, impatiens, begonias, stocks, and marigolds.

There are flowering plants for growing in pots which will thrive in the 55-degree F. temperature. Some of these are hardy and non-hardy primroses (primulas), cyclamen, cineraria, and Christmas and Thanksgiving cactus.

If you start seeds of any of the above, however, most will need a temperature of 68 to 70 degrees F., so you will need an enclosed area with heating cable or other device for good germination. Q I usually grow a few paper-white narcissus each winter on my windowsill, but I really prefer the fragrance of freesias. Is it possible to grow them in pebbles and water as I do the paper whites?

F.S.

Carson City, Nev.

Freesias can be grown indoors if you have a sunny window. They will bloom in good light, without sun, but they will be tall and spindly, making them flop over.

We grow ours in one of the peat-lite (peat moss, vermiculite, and perlite) mixes from the garden store. We pot them up with bulb tips barely covered, water them thoroughly after planting, and store them in our basement refrigerator for about four weeks. Any spot that is about 40 degrees F. is suitable for giving bulbs a chance to form roots before they are brought into the sunshine.

If you can grow them in a room that has a temperature of 50 degrees F. at night, you will have strong stems and perkier blossoms. Keep the soil ``just moist'' at all times.