160 The Principles of Vegetable- Gardening 



planting when tliey can set plants on freshly plowed 

 land. 



If seeds are sown in land which has received heavy 

 applications of concentrated fertilizer, care should be 

 taken that the fertilizer does not come into direct con- 

 tact with the seeds, particularly if nitrate of soda and 

 muriate of potash are used. Ordinary quantities of 

 these materials sown broadcast are harmless. Caution 

 should be exercised when sowing fertilizer in the drill 

 with seeds : germination is often hindered. For a 

 discussion of this subject, see Hicks' ^^Germination of 

 Seeds as Affected by Certain Chemical Fertilizers. 

 Bull. 24, Div. of Botany, U. S. Dept. of Agric. (1900). 



Roberts* has experimented on the influence of ma- 

 nure-water on the vitality of weed seeds in manure 

 ^^by pumping and distributing over the entire mass, the 

 water leached through the manure and caught in a 

 cistern, and repeating the operation about once a week 

 during the summer. Not a single weed seed germ- 

 inated in the several samples of manure so treated, 

 although placed under the most favorable conditions. '' 



The depth at which seeds should be sown depends 

 (1) on the soil, as to whether it is moist or dry, well 

 tilled or poorly tilled ; (2) on the species and size of 

 the seed, and (3) on the season. The finer and moister 

 the soil, the shallower the seeds may be sown. The 

 larger the seeds, the deeper they may be sown. Seeds 

 may be sown shallower in spring than in summer, 

 for at the latter season the surface soil is dry. An 

 old gardener's rule is to cover the seeds to a depth 



*Aniiiial Rep. President Cornell Univ. 1886-7, 73. 



