This section is from the book "Vegetable Gardening", by Ralph L. Watts. Also available from Amazon: Vegetable Gardening.
Proper moisture conditions previous to sowing may be secured in various ways. Fall plowing is often a great advantage in this respect, particularly in the heavier types of soil. There should be no unnecessary loss of moisture after spring or summer plowing, which can be avoided by prompt and thorough harrowing. When seed is to be sown rather late in the season the moisture can be conserved by harrowing at frequent intervals. Another excellent plan, although somewhat troublesome but practicable on a small scale, is to mulch the beds heavily with strawy manure, the coarse particles of which are removed by raking immediately before sowing. Soils which have received heavy annual dressings of manure are seldom too dry for the successful germination of seeds. Although moisture is essential, a surplus is just as disastrous as an insufficient amount.
A suitable temperature is required for each class of seeds. Lettuce, onion, beet, cabbage, cauliflower and many other kinds of seed will germinate at a temperature of 50 degrees F., or even less, although higher temperatures will cause no harm. The seeds of many vegetables, as the tomato, eggplant, bean, pepper and the cucurbits, require much higher temperatures, and they soon rot in cold, damp soils.
 
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