It takes from 45 to 57 days to produce a rose in the greenhouse, depending on variety, time of year, and especially light conditions. A rosebush that is planted in the greenhouse is grown 365 days of the year and is generally kept in production for five to seven years before being replaced. These plants, cycling on a six to eight week schedule, produce about six crops a year. Roses grown in the U.S. and Canada are almost all produced in greenhouses that provide an environmentally controlled climate. This means the rose grower can provide roses on a dependable year round basis not affected by outside temperature variations.
Sunlight is one of the grower s best friends.
Roses need a fairly ample supply of sunlight to bloom properly. It also may provide additional carbon dioxide to supplement the air plants breathe to encourage faster growth. Also, automated systems have been designed to provide the plants with measured amounts of fertilizer with each watering. During the day, the sun often provides ample heat for the greenhouse. However, the clear greenhouse covering quickly radiates heat into the night.