Temperature and Humidity
Second in importance is a cool 65 degrees or even much lower (maximum, 70 degrees), and third is the humidity which keeps the plants at their best. Leaves curl and dry, buds and flowers drop when the air is hot and dry. Miniature roses should not be set anywhere near a heater or radiator of any kind. Unless the air in the growing area is really cool and moist, set the pots on moist gravel or make some other provision for increasing humidity, as outlined on pages 76–77. It even helps to cover the plants with a tent of plastic every night, and let them emerge only for the day.
Watering
Keep the soil always moist, never soggy and muddy, never dry and caked. As a humidifier and refresher, mist the foliage as often as you can.
Fertilizing
A balanced soluble house-plant fertilizer (never one with high nitrogen content) can be fed in half-strength solution every three weeks beginning about three weeks after a freshly potted plant begins active growth. Or you can use any special rose food according to directions and at half the strength recommended on the package. The idea is to encourage the plant to grow and flower, but not stuff it with so much nutrition that it gallops gaily up to nondwarf size with leaves only.
Pruning and Grooming
I seldom prune miniature roses indoors except to cut off cleanly any stems that may have been accidentally broken or that may grow unattractively long or misshapen. I do try to douse the plants in slightly sudsy water, to clean the foliage, every few weeks; and I pick off faded flowers promptly. Actually, instead of being in continual bloom, these plants usually flower for a few weeks and then take a short rest before they send up buds again.
Insects and Disease
Again, preventive spraying is all I’ve ever done. I use my handy house-plant aerosol bomb almost every week. If disaster should strike, I’d probably use the special rose spray or dust I use on the regular garden roses.