ASK THE GARDENERS. Questions & Answers.

Q I have a crown-of-thorns cactus that rarely blooms. Most of the leaves curl up and eventually fall off. I have many cactus in our home and they are doing fine. The crown-of-thorns gets similar treatment. Mrs. W. E. Idaho Falls, Idaho Because of its thorny growth, many folks mistakenly think crown-of-thorns is a cactus. It is euphorbia milii, the same family as poinsettia (E. pulcherrima). All euphorbias have sticky, milky juice in the stems and most need similar care. Crown-of-thorns needs a well-drained soil, which can be one of the peat-lite mixes from garden stores, or homemade with one part garden soil, one part sphagnum peat moss and one part perlite. The soil must be ``just moist'' all the time it is blooming. Some bloom almost continuously if the light is bright enough and they have sufficient moisture. Others may bloom from early spring until fall. When out of bloom, the top inch or two of soil can be dry, but NEVER let the roots dry out. Leaf and flower drop occur when the temperature drops below 60 degrees F. or when the soil is too dry or too wet. Q My staghorn ferns do not look very good. The leaves have brownish tips. Occasionally, I feed them some slow release fertilizer and a little cut up banana peel. C. B. North Fork, Calif.

We assume your staghorn fern is attached to a slab on which has been mounted some sphagnum moss. Most folks drench this moss twice weekly and let it drain before rehanging. The moss should not be allowed to get completely dry; rewater it while it's still damp, but no water can be squeezed from it. Use a balanced liquid fertilizer mixed half strength and substitute it for one of the waterings about once a month in summer and once every six or seven weeks in winter. Hang ferns in an airy place which has bright light but no direct sun. They prefer a night temperature between 55 and 60 degrees F. Day temperatures can go into the 90s as long as ferns are shaded and moss is moist.