Q–What is the secret for getting potted plants of ornamental or flowering cabbage and kale to last indoors?
A–Give them a sunny, airy, cool place, ideally where temperatures range from above freezing to not more than 60 degrees. A sunporch could be the place, or a bright window in a guest room where the heat can be turned off.
The ornamental forms of cabbage and kale are called flowering because they color up in the cool days of autumn like giant flowers, cabbage roses if you will. The green leaves in the early stages of growth are edible the same as the vegetable forms. All are considered cool-weather crops.
A crop of flowering cabbage and kale can also be grown in plant rooms or cool-to-moderate greenhouses by sowing the seeds before Thanksgiving. Warm days, up to 70 degrees, and cool nights, down to a range of 40 to 50, will produce colorful rosettes of leaves 6 to 8 inches across by Valentine`s Day.
The seeds of flowering cabbage and kale are large enough to be handled easily. Sow only a few more than you wish to pot individually and finish in a 6- to 8-inch azalea pot (one three-fourths as tall as it is wide at the top). Barely cover the seeds with planting medium, as they need light in order to sprout. Maintain constantly moist and in a temperature of 70 degrees until the seedlings emerge, then immediately place in the cooler temperatures.
When transplanting seedlings of flowering cabbage and kale, set them deep, up to the lowermost leaves. Use a balanced fertilizer such as 10-10-10 in the early stages, but as the rosettes begin to take shape, withhold all nitrogen, using instead a formula such as Clarel Laboratories` 0-6-5, which will make them color up, along with chilly but frost-free temperatures at night.
Q–What is the proper care of a potted chrysanthemum when the blooms start to fade?
A–Cut all the stems back to 2 inches from the soil. Keep cool and on the dry side until spring. Move to a sunny, moderately warm growing area in March and start watering. Root cuttings of the new shoots in April and discard the old plant.
Success with chrysanthemums, whether they are potted or grown in the garden, depends largely on starting each season with rooted cuttings. At the very least divide old plants, discarding the woody parts at the center and replanting only the most promising new growth from the perimeter.
The flowers on any potted chrysanthemum will last longest if the plant always has an adequate supply of water. If the soil dries enough to wilt the leaves, the life of the flowers will be markedly shortened. It also helps if the plant is placed in an airy, pleasantly cool atmosphere in bright light but with protection from the sun`s hottest direct rays.
Q–I have a vanda orchid about 2 feet tall. The upper half has strong, healthy leaves and vigorous air roots. The bottom half is leafless and the air roots seem shriveled. What do you advise?
A–Remove the orchid from its pot and examine what you find, which will likely be a growing medium that has gone into a rapid state of decomposition and numerous rotted roots. Cut off the dead roots and up the main stem until you reach healthy, living tissue. Repot, using fresh, moistened firbark mixed with some horticultural charcoal chips (about six parts firbark to one of charcoal); set with 6 to 8 inches of the stem and accompanying roots in the pot, carefully filling in with the bark-charcoal mix. Set to grow in a sunny, airy, moist, warm place but go easy on watering until the roots take hold.
Q–I have agreed to participate in the horticulture division at the 1987 New York Flower Show March 7 to 15. It is a challenge class, meaning all who participate will receive the same number of bulbs of Princess Irene tulip, force them in a 7-inch clay bulb pan and bring to bloom at precisely the right moment for the judges` critical eyes. Can you give me a timetable of when to do what?
A–Research tells me that Princess Irene, a single, early, orange-and-purple tulip, 12 to 15 inches tall, needs 19 weeks of cold, then 22 days to force into bloom with 63-degree night temperatures. Presuming that you will not be using precooled bulbs, here is a possible game plan:
On receipt, until potting up, store tulip bulbs at 63 degrees in an airy, dark, dry place.
Tulips grow best in a well-drained, sterilized planting medium having pH of 6.0 to 7.0. Packaged soil-less mediums such as Pro-Mix and Baccto Professional Planting Mix are sometimes used, as well as the usual all-purpose mix of equal parts soil, sand and peat moss.
When potting tulip bulbs, always put the flat side of the bulb facing the rim. This is done so that the lowermost big leaf will develop toward the outside of the pot.
Set bulbs to root in the dark at 48 degrees. Be sure they never lack for moisture.
When roots grow out the bottom of the pot, decrease the temperature to 41 degrees.
When the shoots are about 1 inch tall, decrease the temperature to near freezing, 32 to 35 degrees, to retard shoot growth so that a high quality plant can be produced when actual forcing at 63-degree minimum night temperature begins.
Based on the dates given for the show, it would seem we are talking about beginning the rooting process from mid- to late October, with forcing beginning about three weeks before blooms are desired. This is some challenge, but at the very least you will have some beautiful tulips at home, even if they miss the show deadline.
The instructions I have given so far have been for regular tulip bulbs, not precooled. We also see on the market today an ever-increasing number of tulips that have been precooled and can be brought to bloom as early as Christmas without any special treatment.
Q–I always thought German primrose, Primula obconica, was treated as an annual and discarded after blooming in the winter and spring. This year several of mine survived summer heat and have even started blooming again. Are they worth repotting for another season?
A–Yes, definitely. I would crumble away some of the old planting medium and repot using a packaged soil-less mix such as a Pro-Mix. You could also mix together two parts sphagnum peat moss to one each of soil and clean, sharp sand (or perlite).
If in the unpotting process you discern several crowns or leaf rosettes growing together, division is also possible, so that you may be able to increase considerably your supply. The Clause Co. in France has been breeding new varieties of Primula obconica, with unusually large heads of flowers that are especially strong in the color ranges of blue and apricot. We can look forward to seeing more and more of these in the U.S., with best growth and bloom occurring in cool to moderate temperatures (40 to 70 degrees), in a sunny, airy, moist environment.
Elvin McDonald cannot answer all questions individually, but he will respond to questions of general interest in this column. Write to him c/o The Chicago Tribune, Room 400, 435 N. Michigan Ave., Chicago, Ill. 60611.
