PBOTECTION OP THK SEED-BEDS. 193 



described (Fig 35), -which temper frost and the morning sun and 

 allow the plants to get the benefit of the nightly dews. As they 

 do not prevent sufficient light and heat from reaching the plants, 

 they need not be removed in the day time like the grass tatties. 

 Bamboo trellis-work fixed on supports would be the cheapest 

 form of such cover. In case of severe frost loose grass or a cheap 

 mat could, in addition, be spread over the trelUs work. 



A fourth plan is to cover the ground between the lines with a 

 thick layer of straw, which keeps in the heat of the soil and pre- 

 serves the roots and lower, and generally most sensitive, parts of 

 the stem. The base of the seedlings can be further protected by 

 earthing it up with the aid of the crane-necked (Fig 25) or share 

 (Fig 28) hoes. 



A fifth plan, which may be adopted simultaneously vnth any of 

 the preceding, is to maintain a smouldering fire on the windward 

 side of each bed. Dry, powdered cattle dung, laid in a narrow- 

 deep trench running paralled to, and just outside, the edge of each 

 bed, burns steadily and slowly, requires no watching at all, and 

 gives out the required amount of heat. 



Lastly, to minimise the danger from night-frosts, the vegetation 

 ot the seedlings should be kept back as much as possible during 

 winter by stopping watering or reducing it to the minimum neces- 

 sary to keep the plants aKve. 



C. Protection against excessive insolation. 



Excessive heat may retard the functions of nutrition, or, by 

 overheating active and sensitive tissues, disorganise and kill them ; 

 while too intense sunlight may produce over-transpiration and 

 thus either weaken temporarily or hurt permanently the seedlings. 

 In order to keep the temperature as near the optimum as possible 

 and to prevent transpiration in excess of the moisture taken up by 

 the roots, we must temper the rays of the sun by shading the beds 

 with tatties, mats, thatch, or more or less open trellis-work ; and 

 also, by keeping the soil sufficiently moist and, if necessary, also 

 by covering it over with straw, prevent it from becoming over- 

 heated. It is the afternoon sun from which the beds are chiefly to 

 be shaded. Another plan is to grow along the western edge of 

 each bed a Hue of persistent agricultural plants, such as castor oil, 

 cotton, &c., which at least pay for their maintenance without 

 interfering with the roots of the seedlings. Lucerne, which is a 

 soil-improving crop, may also be sown in lines alternating with 

 the lines of seedlings. 



