DISTANCE OF PLANTING 77 



plants of species in which the seeds are very small and the seedlings 

 delicate. 



Influence of Season on Depth of Planting. — The same kinds 

 of seeds may be planted at different (k^pths in different seasons 

 of the year. Early in the spring, when the soil is barely dry enough 

 to work and is almost too cold for the germination of seeds, it is 

 driest and warmest close to the surface. There is little danger 

 of its drying out too much before the seeds germinate. Under 

 these conditions shallow planting is advisable. On the other hand, 

 in midsummer, when evaporation is rapid and the heat intense, 

 the conditions of both moisture and temperature are likely to be 

 more favorable for germination at a considerable depth below 

 the surface. Under such conditions the seeds should be planted 

 as deeply as the strength of the seedlings will permit. 



Sometimes a general rule is given to the effect that the depth 

 of planting should be four times the diameter of the seed. This 

 is a satisfactory depth under greenhouse conditions; but out-of- 

 doors it is difficult to maintain sufficient moisture for the seed so 

 close to the surface of the soil. In general practice in a humid 

 climate, in soils of medium rather than extremely light or extremely 

 heavy texture, it is customary to plant small seeds, like lettuce, 

 onions, carrots, parsnips, radishes and spinach, from one-half to 

 three-quarters of an inch deep, at the normal time for planting 

 these crops in spring. Large seeds, like beans and corn, are planted 

 from one to three inches deep, depending upon the amount of 

 moisture in the soil and the season of the year. 



DISTANCE OF PLANTING 



The distances at which seeds shall be planted are determined 

 by two factors: The amount of space needed by each plant for 

 normal development during the time it is expected to occupy the 

 given location, and the amount of space needed to properly care 

 for the plants. The former is determined chiefly by the size of 

 the plants at maturity if they are not to be transplanted, or their 

 size at the time of the first shift if they are to be transplanted. 

 The latter is determined chiefly by the method of tillage to be 

 employed, especially by the kind of tools to be used and the power 

 by which they are to be operated. 



Space for Tillage. — Plants growing on a narrow greenhouse 

 bench, the center of which can be reached by a man standing at 

 either side, can be tilled with hand weeders, or similar tools, and 



