Taty,
Greenhouse growers grow a wide variety of crops -- perennials, annuals, and bulbs. The decision you will have to make is: Do you want to specialize in a few crops, or a more diverse offering for your retail florists? And, because greenhouse space is considered prime growing space, we have to double and triple crop. In order to do this, many crops are grown in crates, and are set directly on the ground which has been covered with landscape fabric. However, some crops are planted directly in the soil. For example: tulips which were planted last fall. These bulbs are planted very close--almost touching. Thousands of bulbs can be planted in a bed. A bed 4' wide by 96' long can hold 9,000 tulip bulbs. We plant different cultivars so they wouldn't all have the same bloom time. These are harvested bulb and all because they won't produce as well again the second year. After harvest, the bed is tilled, composted and planted with another crop. This could be an annual such as: giant snapdragons, zinnia, sunflower, or celosia.

A really nice perennial to grow in crates is Dicentra, spectabilis (Bleeding Heart). You can force these to bloom for Valentine's for your retail florists.

We also grow Karma dahlias directly in ground beds. These plants have a fairly long bloom time. They bloom for us here in Michigan from the end of May until late July when our field dahlias are ready for harvest. We cut them back, fertilize and get a little production out of them later in the season when frost has taken our field crop which is usually mid-October. The Karma dahlias are also a good winter greenhouse crop for those growers in a warmer climate than Michigan. Shipment of cuttings began November 7.

Some annuals that are planted directly into ground beds:
Ammi majus
Buplereum
Nigella
Saponaria
Larskpur (which we treat as an annual)
Bells of Ireland
Stock
Salvia leucantha
Sweet Peas
Poppies
Sweet William
Lisianthus
Phlox

Here are some perennial and bulb crops grown in crates:
Anemones
Ranuculus
Crocosmia
Eremerus
Foxglove
Delphinium
L.A. and Asi-Florum Lily
Oriental Lily
Dutch Iris
Freesia
Hortweggi Lupines
Amaryllis
Allium
Columbines

Trish