LIST OF FORCING CROPS. 5 
perature of 55° or below, and a day temperature of 65° to 
70°. The plants of this category are : 
Lettuce, 
Asparagus, 
Rhubarb, 
Cauliflower, 
Pea, 
Carrot, 
Beet, 
Radish, 
Cress, mustard, mints, parsley, 
Onion, 
Spinach, 
Celery, 
Pepino. 
The warm plants demand a night temperature above 55°, 
and the day temperature may run above 75° when the 
weather is clear and bright. They are: 
Tomato, 
Eggplant, 
Pepper, 
Cucumber, 
Muskmelon, 
Bean, 
Cyphomandra. 
The above categories comprise about all the species of 
vegetables which are actually forced for market in this 
country, and even of this short list there are a number for 
which the market is so limited, or the methods of grow- 
ing them so little understood, that they really have no 
place in the staple demands of the market. Vegetables of 
very minor importance asa forced crop are peas, carrots, 
beets, cress, celery, eggplant, and pepper. In fact, there 
are only three staple commercial forced vegetables, and 
these, in the order of their commercial importance, are 
lettuce, tomatoes, and cucumbers. 
