345 
Farmers generally know the importance of having what is commonly 
-called a good seed bed, which is obtained when the soil is moderately 
moist, and can be well pulverized—made as mellow as an ash heap. If 
a soil is too wet either from heavy or continued rain, or want of draining, 
the temperature is reduced, the particles of soil j>ack or adhere closely 
together, and the quantity of air in the soil is thus diminished: The 
germination of seeds under these circumstances is retarded, and many 
perish without vegetating. In a moist soil well pulverized, the particles 
do not adhere so closely together, the spaces between are filled with air, 
and the temperature is higher, the germination of the seed is consequently 
more certain, and the vigor of the young plants greater than in the 
former case. 
The depth at which seed should be sown- varies to some extent with 
the kind of seed, and the character of the soil. If wheat is sown more 
than about one inch deep, it is found to have two setts of roots; which 
have been called the seminal and coronal roots. The former originate 
where the seed germinates, the latter from just below the surface of the 
soil, whether grain is sown deep or superficial. A hasty conclusion was 
formerly arrived at that the lower tier of roots served to provide the 
plant with nourishment during winter, when the surface soil was frozen. 
Col. Le Conteur, the author of a very useful treatise on the wheat plant, 
considering this notion to be plausible and consonant to common sense, 
ploughed in some fine Dantzic wheat about 7 or 8 inches deep. The 
consequence was that “a vast quantity of the seed rotted instead of ger¬ 
minating, and proved a very losing crop, much to his regret and morti¬ 
fication.” Col. Le Conteur very justly remarks that ‘nature has in some 
measure pointed out that wheat may be sown quite superficial, as self-sown 
wheat is frequently seen very rich and fine.’ I suspect that the forma¬ 
tion of these roots immediately below the surface is a well-directed effort 
of the plant to improve its position, and indicates the depth which it is 
most advisable to sow the seed. The bulbs of different species of plants 
are formed naturally at different depths in the soil, some resting on the 
surface, others being several inches below. A tulip forms its offsets or 
3 r oung bulbs usually at the base of the stem, but I have met wit!* an in¬ 
stance where a tulip bulb had been planted too deep, and the fresh bulb, 
instead of being formed at the base of the stem, was situated two or three 
inches above. Some species of orchids have tuberous roots, usually two. 
