FORCING 



597 



furnishes as nearly as possible the best condition for 

 forced crops. However, an even-span or shed-roof 

 house fjrows many crops to a high degree of perfection. 

 As to the inside arrangement of the house, the crops 

 to be grown will have much to do in the matter. Cool- 

 house crops, as lettuce, radish, and the like, are well 

 grown in solid beds; while heat-loving plants, as toma- 

 toes, cucumbers, melons, etc., should be planted on 

 benches built over the pipes. This means that the cost 

 of building a greenhouse depends very much on what 

 crop one expects to grow. The saving in benches and 

 heat in houses devoted to cold crops is considerable, 

 while the ease with which such crops may be grown 

 recommends them to the beginner. 



The best paying crops are probably cucumbers and 

 tomatoes; the most exacting, melons. The demand for 

 melons, however, is limited, and the cost of producing 

 good flavored, well ripened fruits in winter is hit;:h. 

 Having stated what we conceive to be underlying 

 principles in the winter Forcing of all vegetables, we 

 may consider each of the important crops separately. 



Lettuce. — The ideal soil for lettuce would be a well 

 drained gravelly or sandy loam, but with care in water- 

 ing a soil of heavy texture may be made to produce ex- 

 cellent crops of the loose, open varieties. The heading 

 or cabbage lettuce is more exacting if a fine quality is 

 desired. The first crop of lettuce from the houses 

 should be ready to use by the middle of November, For 

 this crop seed should be sown in September, allowing 

 on an average from 6 to 8 weeks for the crop to mature. 

 A temperature of 55°-60° through the day, with a drop 

 to 40° or 45° at night, will suit all varieties, but in the 

 case of the heading varieties a rise of 5 to 10° at the 

 time of heading will finish off the crop more uniformly. 



Radishes require the same general treatment as let- 

 tuce and may bo grown in the same house. As radishes 

 mature in about half the time lettuce does, the radish 

 seed may be sown between the rows of young lettuce 

 plants, and the product is out of the way when the let- 

 tuce begins to need the entire space. 



Tomatoes being a hothouse crop, require a tempera- 

 ture of 75° by day, with a drop of about 5°-10° at 

 night. This is one of the crops which is dependent on 

 the sun, because the pollen must be dry and light in or- 

 der to pollinate the pistils and produce fruits. The soil 

 for tomatoes may be on the heavy order, and contain a 

 large proportion of fibrous loam, with well rotted ma- 

 nure. As to chemical fertilizers, the best results are to 

 be obtained not from those rich in nitrogen, but from pot- 

 ash and phosphoric acid, as these elements are largely 

 responsible for a slower growth of plant and fruit and 

 a firmer texture and higher flavor of marketable product. 

 To obtain a good yield of fruit through the winter 

 months, it will be necessary to pollinate each flower. 

 This may be done very rapidly. The pollen is jarred 

 into a spoon-like receptacle, and the end of the pistil is 

 touched with the accumulated pollen. As spring ap- 

 proaches and the sun becomes stronger, a simple jar- 

 ring of the plants is all that is needed. As to training, 

 the single-stem method has been found to be the best, 

 as the plants can be set much closer and still allow 

 plenty of room to work around each one. This method 

 consists in the pinching out of all lateral growths. 

 Train the stem to a cord, and support the heaviest clus- 

 ters by strings (Fig. 844). Plants from seeds sown in 

 August will ripen fruits about the first of January, and 

 should continue in bearing until May. A succession 

 may be had by growing fresh lots in pots or boxes to 

 take the place of exhausted plants. The season of 

 forced tomatoes may be thus continued until the out- 

 door product fills the market. 



Cuctinibers arc much forced in the eastern states. 

 Cucumbers are a very exacting crop, and need special 

 care in growing. The White Spine type is perhaps 

 more generally grown in this country than the long 

 Forcing cucumber of the Old World, which has been 

 grown and selected for its Forcing qualities for many 

 years. One of the reasons why the former is the more 

 generally grown is its adaptability to relatively unfav- 

 orable conditions. It grows in the full sunlight, is more 

 able to resist attacks of mildew and red spider, and sets 

 its fruit with more freedom than the Old World types. 

 One other reason may be that the people of this country 



