SELF-MAINTAINING FERTILITY 217 



they are rendered powerless in swamps and cold, 

 wet, sour soils. You can give them increased life, 

 increased vigor, increased efficiency, by adding to 

 their air supply, by keeping the soil loose! And 

 there you have the whole, simple key to the entire 

 secret of plant-food production. Cultivate the soil, 

 help the bacteria to grow and work, give them, 

 occasionally, manure to work on and they will feed 

 your plants. And then, if you wish to augment 

 their effects and to still further stimulate vegeta- 

 ble growth, you can use liquid manures, prepared 

 fertilizers, and the like, just as you use beef tea, 

 canned goods, etc., to supplement the efforts of the 

 cook and the gardener. 



WHAT CERTAIN PLANTS LIKE BEST 



It would be perfectly true to say that any kind of 

 fertilizer will help plants grow. But it would not 

 be a sensible nor an economical statement to make, 

 any more than you would say that any kind of food 

 is best for every person. As there are preferences 

 among persons, so too there are special needs 

 among plants. In the garden are a few distinct 

 types of vegetables, each of which appreciates a 

 little different treatment. You might just as well 

 know these, and thereby be enabled to act intel- 

 ligently and to get the best possible results when 

 you do fertilize. 



Group i. Tubers and roots, including potatoes 

 parsnips, carrots and beets. These need less manure 

 (meaning coarse mixtures of bedding and horse, 



