6. The Practical Greenhouse for You  — Cold, Cool, or Warm

The temperature you maintain in your greenhouse plays an important part in plant growth. Greenhouses are classified as cold houses (unheated), cool houses (55 to 60 degrees at night), or warm houses (60 to 70 degrees at night). Whenever night temperatures are cited you should figure on a daytime requirement about 10 degrees higher. Each of these three classes of greenhouses is suitable for growing certain kinds of salable plants.

THE UNHEATED GREENHOUSE

If you live where outdoor night temperatures never dip be­low 32 degrees, you can run a cold (unheated) greenhouse the year round. Otherwise, you might find it profitable to operate a cold greenhouse until late fall, close it down during the cold­est winter months, then resume operations in early spring. In such a house, you can make money on annuals, spring-flowering bulbs, and bedding plants by forcing or starting them in late February or early March. The cold greenhouse is also an excel­lent place for growing lettuce.

In summer, use the unheated greenhouse for tomatoes, seed­ling perennials, or almost any plant that flowers in summer. In this type of greenhouse, winter-grown plants should be planted directly into the bench soil. Here they will withstand lower temperatures than if planted in pots. In the following lists are plants I have found profitable to grow under the various condi­tions specified.

FLOWERING PLANTS FOR THE UNHEATED GREENHOUSE

Spring
Anemone*        Larkspur
Astilbe  Lily-of-the-Valley
Carnation          Narcissus*
Columbine         Pansies
Crocus*            Primrose
Cyclamen*        Saxifraga
Daffodil*          Scilla*
Forget-me-not   Sedum
(Myosotis)        Tulip*
Fritillaria*          Viola
Hyacinth*         Violet
Iris*

Summer
Begonia (Tuberous and  Campanula
semperflorens) Canna*
Browallia   Carnation
Calceolaria  Celosia
(* Denotes plant usually grown from a bulb, corm, or tuber.)
Chrysanthemum   Hibiscus
Crinum*               Lobelia
Delphinium           Oxalis *
Dutchman's Pipe  Petunia
(Aristolochia)      Sedum
Flowering Tobacco       Sweet Peas
(Nicotiana)         Tigr idia *
Geranium             Vallota*
(Pelargonium)    Watsonia *
Autumn
Carnation             Nerine*
Chrysanthemum   Sternbergia*
Gladiolus*                Sedum
Hosta*                 Sempervivum
Kniphofia*           Zephryanthes
Lily*
Winter
Anemone*           Iris alata9
Crocus*               Jasmine
Cyclamen neapolitanum*       Saxifraga
Erica                    Solanum
Fatsia                   Viburnum
Freesia*               Violets

THE COOL GREENHOUSE

In the cool house the night temperature in winter should be about 55 to 60 degrees with the usual rise of 10 degrees during the day. In this temperature range, you can grow a variety of plants including all of those suggested for the unheated greenhouse, as well as the plants in the following list, and your heating costs will be far less than those in a warm house of the same size

18. The free-standing greenhouse of Mrs. Marion Hughes, Galesburg, Michigan demonstrates the convenience of slat shading; it can be rolled down whenever needed, in end or side sections, as dictated by the sun. (Photograph by Hughes)

FLOWERING PLANTS FOR THE COOL HOUSE

(Winter night temperature: 55-60 degrees.)
Spring
Aquilegia
(Columbine) Azalea Browallia
Camellia Carnation Cineraria Clematis
The  Practical Greenhouse for You
Clivia*          Lachenalia*
Convallaria       Lilium*
(Lily-of-the-V'alley) *  Nasturtium
Freesia a       (Tropaeolum)
Geranium    Rhododendron
(Pelargonium)
Summer

Achimenes*         Clematis
Agapanthus*       Morning Glory
Asarina               (Convolvulus)
(Maurandia)      Cup-and-Saucer Vine
Begonia              (Cobea scandens)
(all types)            Crinum *
Bougainvillea       Datura
Cacti                   Fuchsia
(Some varieties)   Habranthus0
Caladium*           Hoya
Calceolaria          Hydrangea
Campanula          Impatiens
Canna*               Lantana
Carnation
Autumn

Bignonia              Mignonette
Browallia             Nerine*
Chrysanthemum   Salvia
Fatsia                  Streptocarpus
Flowering Maple Vallota*
(Abutilon)

19. Profit "right in your own back yard." Could the neighbors, or anyone, resist taking home some part of this lush preview of spring? (Greenhouse of Ruth Marie Peters; photograph by Roche)

Winter
Begonia                Chrysanthemum
(Fibrous-rooted)  Cineraria
Bouvardia            Cyclamen*
Carnation             Stocks
Christmas Rose
(Helleborus Niger)

THE WARM HOUSE

The actual temperature range of a warm house is 60 to 70 degrees during winter nights. However, most of those who grow African violets, gloxinias, and so forth, as well as foliage plants of tropical origin and nature, find they get more rapid leaf growth and plant increase when the night temperature is 2 to 5 degrees higher than that range. The warm house is also used for growing many of the "stove" plants described in old garden encyclopedias and English gardening books.

FLOWERING PLANTS FOR THE WARM HOUSE

(Winter night temperatures: 60-70 degrees.) Spring
Acacia                  Bromeliads
Aeschynanthus          (various species)
(Trichosporum)   Calceolaria
Amaryllis*            Camellia
Arum*                  Carnation
Azalea                  Cineraria
Begonias               Epiphyllum
(Tuberous,*  semperflorens,     Episcia
some rex)              Freesia*

20. This lean-to may be a bit cramped for the grower but not for the plants, and it will produce dollars. Every inch of space is organized. Note the electric cable for automatic control of the ventilators.   (Photograph  by Gottscho-Schleisner)

for You
Geranium                    Kohleria*
(Pelargonium)    Primrose
Gloxinia"              African violet
Haeman thus *           (Saintpaulia)
Kalanchoe           Streptocarpus
Summer
Achimenes*         Datura
Begonia               Fuchsia
(Tuberous,* semperflorens)    Geranium
Bouvardia                       (Pelargonium)
Bromeliads           Gloxinia*
Campanula           Gloxinera*
Canna*                Impatiens
Crinum*               Oxalis*
Cup-and-Saucer Vine   Passiflora
(Cobea scandens)        Petunia
Autumn
Begonia               Chrysanthemum
(Tuberous,* semperflorens)    Gloxinera*
Bromeliads           Salvia
Canna*                Vallota*
Winter
Ardisia                 Cyclamen*
Azalea                 Gardenia
Carnation             Hyacinth*
Chrysanthemum   Narcissus*
Cineraria              Primula
Citrus                   Rivina humilus
Coleus                 Solanum

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