Growing Roses in a Condo

Rose Location and Light

• Miniature roses grow best with at least five to six hours of direct sunlight per day. Larger rose varieties tolerate partial shade but need at least some direct sun. In a condo, roses grow best in a west- or south-facing window that receives plentiful sunlight. If your condo does not have the required amount of direct sunlight or if you want repeat-blooming roses, provide supplementary fluorescent light to give your plants more than five or six hours of light each day. Roses also grow best when they receive ventilation to prevent fungal diseases. Use a fan to help air circulate or open the windows during warm weather.

Temperature and Humidity

• Roses grow best with daytime temperatures in the low 70s Fahrenheit range and nighttime temperatures in the 60s. By giving roses plenty of light and providing these temperatures indoors, you can force miniature roses to bloom during winter. Miniature roses require more humidity than most households generally have, especially in non-humid parts of the country. The ideal humidity level for miniature roses is between 50 and 55 percent. To increase humidity around the plants, put potted roses on moist gravel trays or place open jars of water among rose pots.

Planting Medium

• Roses need good soil drainage, and they do well in a planting mixture containing 10 percent sand, 45 percent soil and 45 percent peat moss. A pre-mixed peat moss with a bit of vermiculite and fertilizer makes your roses perform well. The mixture should be sterile, and you can heat treat in the oven at 100-to-200 degrees for an hour to sterilize it yourself. The Maryland Rose Society recommends adding a tablespoon of superphosphate, a teaspoon of dolomitic lime and a tablespoon of bone meal for every gallon of potting mixture. Miniature roses need at least a 6-inch diameter pot. Some larger rose varieties can have a spread of a few feet, so they do best with a wider pot, based on the size of the variety.

Care

• Roses require even moisture but do not like overly soggy soil. Water them when the top 3/4 inch of soil feels dry to the touch. Soak the soil thoroughly so that water runs out of the bottom of the pot's drainage holes. Do not let excess water sit at the bottom of the pot in a tray. When roses flower, apply a complete rose fertilizer once or twice per month. If you use a slow release fertilizer, apply it by sprinkling pellets on the soil; if you prefer a water-soluble liquid fertilizer, mix it with water before applying it to the plants. Apply fertilizer carefully in accordance with the manufacturer's instructions, because excessive fertilizer slows flowering. Prune miniature roses after their blooms fade during the summer and fall. An easy way to do this is to shear the tops of the plants with a hedge trimmer. To prune larger roses, remove weak or overly crowded canes during the spring and remove spent blooms later in the growing season.

Pests and Problems

• Spider mites and aphids both like to feed on roses, causing lightened foliage and distortion as they suck the juices out of the plant. Get rid of these and other large insects by spraying them with a strong stream of water. Alternatively, dip the plant foliage into an insecticide solution indicated for the specific type of pest, such as Mavrik for spider mites and Orthene for aphids. Roses are also susceptible to fungal growth, such as powdery mildew and black spot. Besides preventing fungal problems by providing plenty of ventilation around the plants, you can also reduce fungal diseases by dipping the foliage into a fungicide solution once every seven-to-10 days. If you choose to spray an insecticide or fungicide rather than dipping your rose bush, always spray outdoors to avoid inhalation of harmful chemicals. It is also important to make sure to apply chemicals at the manufacturer's recommended rates to avoid harming the plant or creating a health hazard.