40 EXPERIMENTS WITH PLANTS 



ers, etc.). In sowing seed in the garden, the simplest 

 and most effective way is to press a board edgewise 



into the soil to the right 

 depth, place the seeds 

 in the depression, fill it 

 with earth and pack it 



35."Tpl a nting stick, to secure uniform depth firmly by preSSHlg the 



in plants seeds. board down upon it. A 



board such as is shown in Fig. 35 may be used to 

 secure a uniform depth. , 



The circulation of air in the soil will depend on the 

 way in which it is packed in the box, on the condition 

 of the surface (whether a crust forms or not), on the 

 kind of soil used arid on the amount of moisture in 

 the soil. It will be found worth while to vary the 

 conditions by filling one box with sand, another with 

 clay and another with a mixture of equal parts of sand 

 and old loam, which makes a very excellent soil for 

 seeds. Water the boxes equally throughout the ex- 

 periment. Gardeners always recognize the necessity 

 for "good drainage" (i. e., proper circulation of air 

 in the soil), and secure it in a variety of ways. The 

 seeds are usually sown in shallow boxes, porous earthen 

 dishes, or in ordinary pots, in which case a layer of 

 pebbles or pieces of broken pots is placed in the bot- 

 tom. The surface of the soil is protected from baking 

 (which forms a crust) by a cover of sawdust or litter, 

 or by being shaded; the shade is also of value in 



