MISCELLANEOUS VEGETABLES 367 
Fig. 129.—Kohl-rabi at the Ohio State University. 
required for lettuce. If desired, special plants may be 
grown in the open and transferred to the house in the fall. 
The demand for mint is very limited. 
MUSTARD 
Mustard is grown under glass, to a limited extent, for 
salad purposes and also for greens. Chinese, a broad- 
leafed variety well adapted to greenhouse culture, will 
make more herbage than any other variety. The most 
economical use of space is to start the plants in flats and 
transplant seedlings of large size into beds where the crop 
is to be grown. The plants may be set 6 to 8 inches 
apart. Mustard requires practically the same cultural 
conditions as lettuce. 
ONION 
The onion is forced to some extent for commercial pur- 
poses. It requires the same conditions of heat and mois- 
ture as lettuce, though it is more hardy. Sets of any of 
