I50 



The Great World's Farm 



warmth. Maize, as might be expected, requires more 

 heat than any other corn, and will not start until the ther- 

 mometer shows about fifteen and one-half degrees above 

 freezing, and even then grows but slowly; and cucumber- 

 seed shows no sign of life without still more heat. 



But, though many seeds will make a start in cold 

 weather, even in frost, it does not follow that they will do 

 more than start; for a plant requires different degrees of 

 light and heat at different times in its life. And if it does 

 not receive enough at the important period when it has 

 done growing, and is going to blossom, the chances are 

 that it, will bear no fruit. For fruit cannot do much 

 towards feeding itself, and though it does take up carbon 

 from the air, it is chiefly dependent for nourishment upon 

 the leaves, the great food manufacturers. But in a cold 

 summer, the leaves, instead of passing on their stock of 

 food to the fruit, and themselves turning yellow, as they 

 ought to do, seem to be quite thrown out of their calcu- 

 lations. They keep their food to themselves, and remain 

 green and juicy, while the fruit is starved, and its develop- 

 ment checked. In very bad cases, the plant puts out new 

 shoots, and the crop never comes to perfection; for the 

 heat which is quite sufficient for the growth of stems and 

 leaves is not sufficient for the growth and ripening of the 

 fruit. 



If, on the other hand, the plant gets too much light 

 and heat at an early stage in its life, it growls up and 

 ripens its fruit too quickly, before it is properly developed; 

 and this is what takes place when crops are sown too late 

 in the year. In the ordinary course of nature, seed 

 generally drops and sows itself as soon as it is ripe, and 

 begins to grow forthwith. But it cannot go on growing. 



