Long stem roses, the national flower of America, and carnations
are two examples of cut-flower crops grown in the greenhouse.
Roses are grown in beds on the floor of greenhouses and the
plants produce cuttings for about 5 years. The roses receive a full
day of natural sunlight, and specialized lightbulbs extend the
total amount of light up to 18 hours per day. This way, the plants
can be cut four times a year and harvests are timed for Christmas,
Valentine’s Day, Easter, and Mother’s Day.
Flowering potted plants include poinsettias, marketed around
the winter holidays, and geraniums that are very popular from
Mother’s Day through Memorial Day. Poinsettias may have
their photoperiod manipulated by bursts of infrared light in
order to time the bloom for the holidays. Green plants—which
are sometimes called foliage plants or houseplants and include
philodendrons, ficus, and ferns—are also grown for sale in pots
or hanging baskets.
|Figure 6.3 Bedding plants are often grown in
greenhouses, such as at the Plantorium in
LaPorte, Colorado, pictured above.
Bedding plants are raised for sale to consumers who plant them
in their gardens or window boxes and include about 50 different
types of flowers and vegetables (Figure 6.3). These crops are started
in plastic trays called plugs, which are mechanically watered and
fertilized. The seedlings are transferred into the flats, small containers,
or small pots that are found at the garden center.