PLANT CHEMISTRY J 101 



others strong enough to eat metals, tmt tire 'plant 'rooi acid 

 is very weak. It is strong enough, however, to dissolve the 

 food that it needs, in order to make the solution which, by 

 osmosis, will pass through the walls. And if we grind our 

 fertilizers very fine, so that the root-hairs can easily get at it, 

 then the plants flourish the better. 



The kinds of fertilizers which can be bought are so many 

 as to puzzle any one who is not an expert. It is true that if 

 one is to grow large crops of single kinds, such as potatoes 

 or corn, one should buy special fertilizers. For corn naturally 

 needs one kind of food, while potatoes need another. But 

 for the gardener, who has at most but a few rows of each, it 

 is impossible to have a fertilizer fpr every crop. I will 

 tell you, then, the simplest method of buying and using fer- 

 tilizers. 



In the first place, buy of a man whose word can be trusted, 

 and buy of him only "high grade" fertilizers. " Low grade," 

 though cheaper, are too cheap to be worth getting. Next, 

 buy but two kinds, since our garden crops can be divided 

 into two groups of plants. 



In the first group stand all those which are grown for their 

 leaves and stalks : spinach, chard, cabbage, onions, cauli- 

 flower (which we never allow to go to seed), beets for greens 

 or for very young beets, asparagus, lettuce, celery, parsley. 



In the second class are the plants grown for their roots or 

 fruit or seed : peas, beans, the squashes (with cucumber, 

 melons, marrows), tomatoes, turnips, carrots, winter beets, 

 parsnips, radishes, corn, potatoes, flowering plants. 



The differences between the two are these. In the first class 

 are all the plants which are to grow rapidly and luxuriantly. 

 We want such plants to be slow in making flowers and seed, 

 or in storing food in the roots. In the second group are all the 

 plants which we wish to be quick in flowering, in making 



