Yes, it's possible: miniature roses as house plants

Flower & Garden Magazine, Oct-Nov, 1985 by Mary E. Poynter

Although my romance with miniature roses goes back many years, I find it strengthening with the passage of time. Observing and growing these tiny plants, which are replicas of larger roses in bloom, foliage, and even thorns -- is a fascinating experience. Furthermore, they are delightful house plants that bloom indoors from late fall through the next summer, or year around if you prefer.

I am sure some would challenge my enthusiasm because of unsuccessful past experiences. Common faults they might cite are invasion of red spider mites, failure to bloom, blooms that are too sparse, and excessive leaf droppage. Good handling goes a long way in solving such problems, but of even more importance is making the right choices of varieties to grow indoors. I have found some varieties that did not do well at all; but also I have found many that thrive when their requirements are met.

As an example, you don't buy a hanging basket of 'Red Cascade' and place it in a north window and expect it to bloom for you all winter. It is next to impossible to bring this plant into bloom indoors under even the best of conditions, because it requires nearly full summer sun.

The key to success with miniature roses indoors is to know the needs of the varieties you wish to grow, and then to be able to meet those requirements. Or, vice versa, to choose varieties whose needs match the conditions you have.

Three basic needs of all roses are adequate light, humidity of at least 40 per cent, and moderate temperature. Insects and diseases need not be problems because they can be prevented.

Miniature roses need all the light you can give them. Indoors, the best exposure is a south or west window where no trees or buildings block the sunlight. They can be grown also entirely under fluorescent lights. Fixtures with four 40-watt broad-spectrum lamps are usually recommended. When I moved to smaller living quarters, however, I had to find varieties that would do well under just two 40-watt tubes in a regular shop-light fixture. I use Agro-Lite tubes in this fixture, which hangs just three to four inches above the foliage and is turned on 14 to 16 hours a day.

You can also combine fluorescent lighting with natural sunlight. I grow eight micro-mini roses in my living room on a stereo that receives filtered light most of the day, supplemented in evening by two 20-watt Agro-Lites. These are what I call my "display roses," special ones for friends and neighbors to admire.

The humidity and temperature range for miniature roses is similar to that considered ideal for people -- 50 per cent humidity, and 72 degrees F. temperature. Nighttime temperature ten degrees cooler is desirable.

Variation of a few degrees either way will not matter, nor will slightly less humidity. The more humidity the better, up to 60 per cent, and ways of providing this are grouping plants together in trays of moist pebbles or sand, and frequent misting with room temperature water. Moisture (humidity) in the air discourages spider mites. Air circulation is needed, and in winter I provide this by opening outside doors several times a day. You might open a window a few inches in the next room but not where cold wind blows directly on the plants.

Purchase clean, disease-free plants from a reputable nursery, and you should have very few pest or disease problems. I get my plants by mail order. Every Saturday is shower day, when I take plants to the kitchen sink with its spray hose. Holding the plant upside down with my hand covering the soil, I direct a strong spray of warm water on the underside of foliage. Turning the plant over, I spray the top side. This treatment washes household dust, disease organisms and insects from the foliage. If you do this faithfully every week, you probably will not need ever to use poison sprays on your plants.

The time may come, however, when a chemical spray is needed. For this you can use any spray designed for roses, following instructions on the package. Such spraying is usually repeated every seven to ten days, starting as soon as leaves develop. Do this spraying outside of your living quarters, of course.

All roses must have a dormant period, and it is during this dormancy, after the first of January, that it is well to purchase them. They will arrive with few if any leaves, in small two- or three-inch pots. Repot them immediately into pots one size larger. Use any kind of pot that has good drainage. I prefer the hard plastic pots over the clay type, as not only are they less expensive, but water does not evaporate through the sides. Microminis do well in three- to five-inch pots, and regular miniatures in six-inch pots.

A good soil mix is made from two parts coarse sphagnum peat, one part coarse perlite, and one part horticultural vermiculite with a dusting of dolomite limestone added. This mix can be made in any desired amount and stored for use later. Into this you can mix a little slow-release fertilizer such as Osmocote 14-14-14. Minute amounts will be released into the soil with each watering. Or, you can substitute a water and fertilizer solution for the feeding. I prefer to use this at one-fourth the recommended dilution rate, and I use it three out of every four times I water.