DAMPING OFF 133 



Damping Off. Damping off of seedlings is due to a fungus 

 which attacks the tender growth when there is too much surface 

 moisture. It may be produced by rather a small amount of water, 

 providing the soil is heavy and the water is not rapidly absorbed 

 and distributed. On the other hand, a lighter soil taking water 

 more easily may grow plants without damping off, even though a 

 great deal more water has been used than on the heavier soil. Too 

 much shade which prevents the sun from drying the surface soil 

 is also likely to produce damping off, therefore one has to provide 

 for just the right amount of shade and the right amount of venti- 

 lation through circulation of the air, etc. The use of sand on the 

 surface of a heavier soil may save plants from damping off, be- 

 cause the sand passes the water quickly and dries, while a heavier 

 surface soil would remain soggy. Lime may be of advantage if not 

 used in too great quantities because it disintegrates the surface of the 

 soil and helps to produce a dryness which is desirable. Success in 

 keeping the surface dry enough and yet providing the seedlings 

 with moisture for a free and satisfactory growth is a matter which 

 must be determined by experience and good judgment and cannot 

 be completely covered by any formula or prescription. Damping 

 off may be reduced or prevented by sterilization of the soil before 

 planting by using a pan-like cover of the surface and admitting 

 live steam under the cover and raising the surface to a high heat 

 but this is a process too elaborate for small growers to undertake. 



Covering for Beds and Frames. California growers largely 

 substitute cloth for glass in covering hot-beds or cold frames, be- 

 cause it gives all the protection needed, is also rather more of a 

 safeguard against over-heating and furnishes shade from too in- 

 tense sun heat which is liable to come on any winter day and do 

 harm. This is an especially valuable feature in amateur growing 

 where one's attention is apt to be distracted by other affairs. Be- 

 sides, the cloth is of nominal cost. In the drier parts of the state 

 the cloth is used without preparation. Where rains are more fre- 

 quent water-proofing is desirable. Take white cloth of a close 

 texture, stretch it, and nail it on frames of any size you wish, 

 putting in cross-bars to sustain the cloth if the frame is large. 

 Mix two ounces of lime water, four ounces of linseed oil, one ounce 

 of white of eggs separately, two ounces of yolk of eggs; mix the 

 lime and oil with a very gentle heat ; beat the eggs separately and mix 

 with the former. Spread the mixture with a paint-brush on the 



