58 Gardening Under Glass 



the soil is a medley of chemical explosions, and 

 the terrific warfare of deadly enemies, and the 

 constant labor of sappers and engineers, tearing 

 down and bnilding up continuously! 



Now the gardener is, in a sense, the ruler of 

 this invisible empire. In greenhouse work its 

 needs are almost solely in his own hands. And 

 when he understands what things he is responsi- 

 ble for, the fun of growing plants will have a new 

 and fascinating interest. When he understands 

 the routine of mixing soil, and adding manure 

 to it, and providing drainage and all the rest, he 

 cannot but count it as a great adventure. 



What Soil Must Be for Plants to Thrive in It 



Now we do not want to enter into a long dis- 

 course on the "technical aspects of agricultural 

 bacteriology" — but the gardener will be a better 

 gardener if he knows something about soil. 

 Here are a few essential facts to memorize: 



1. That the presence of certain friendly bacteria 

 in the soil is necessary to healthy growth. 



2. That these bacteria are discouraged by soil 

 that is too wet, or too dry. They like a 50 

 per cent, saturation — in other words, a nice, 

 evenly moist soil. 



3. To keep the soil evenly moist, it is necessarj^ 

 to have in it a large percentage of spongy, ab- 



