The Bulletin. 15 



COVERS. 



The cotton cloth used for covering frames for winter lettuce-grow- 

 ing must be sufficiently white and thin to admit light to the plants in 

 bad weather, yet strong and heavy enough to be durable and to stand 

 stretching. What is known as "Heavy Domestic," running 3 yards to 

 the pound, is found to best satisfy these requirements. This cloth 

 is 30 inches wide and costs about 8 cents per yard. Exclusive of 

 walks it takes approximately 4,300 yards to cover an acre. At 8 

 cents per yard the cost of covering an acre would be $344. This 

 is one of the most expensive features of lettuce culture in frames. 



Methods of Fastening Covers.— Covers last longer where they are 

 entirely detachable from the frames, but in cold weather it is found 

 that the heat can better be retained if the covers are securely tacked 

 or slatted to the rear of the beds. There are various devices in use 

 for fastening down the edges of the covers. A simple and common 

 method is to sew straps or loops of cloth to the edges of the cover 

 every 4 feet and to hook these over wire nails driven in the outside 

 of the frame. Small brass rings may be substituted for the cloth 

 loops. Still another method is to tie a marble or small pebble into 

 the edge of the cloth Avith fishermen's heavy seine twine and to loop 

 the cord over a wire nail. These methods have the disadvantage that 

 with the warping of the frames and the shrinking of the covers it is 

 often difficult to make loop and nail meet. The most satisfactory 

 method we have yet tried for fastening covers is the turning of a 

 narrow hem on the edge of the cover and threading through this a 

 %-inch rope. This rope may be quickly fastened down, no matter 

 what the position of the nail, and it holds the cover securely. The 

 rope is also a great protection to the covers when the beds are being 

 exposed daily. Without the rope we have found that in uncovering 

 long beds the covers are apt to be ripped and torn by the men pulling 

 them in too long stretches. Rope %-inch size costs about 12 cents 

 and runs about 24 feet per pound. For narrow frames it would 

 require about 3,600 feet of rope per acre, the cost of which would 

 be $18, and for wide ones $14. With short lengths covers are some- 

 times handled on rollers. This keeps the cloth in good condition and 

 the weight of the roller holds the cloth taut and secure in windy 

 weather. Rollers, however, are difficult to handle on long beds, and 

 for that reason have never come into general use. 



With good care covers should last three or four years. Oiling the 

 covers was found to destroy their elasticity and cause them to crack 

 and break. Wliite-washing the covers, as sailors do their canvas, 

 would undoubtedly destroy fungous rots and lengthen the time of use- 

 fulness of the cloth. When not in use the covers should be folded 

 up when dried and stored in a dry loft. 



