HOW TO GROW AND MARKET FRUIT 



air will send the frosty atmosphere down, down, down, to 

 lower levels, by any open paths it can find. 



Of course the exposed top of a mountain is likely to be 

 affected by any frost in the air on still nights, but here, if any- 

 where, there is likely to be a breeze to drive the frost away. 

 The sides of a hill, whether benched or sloping, usually will 

 be free from frost when the bottom below is hoary. Low flats 

 or pockets of land are frost traps, as they catch and hold the 

 cold air that drains from the land above. If a valley is long, 

 with an even fall and few obstructions, there may be a good 

 flow of air along its floor. This will prevent frost. In such 

 places the very finest lands for fruits are found, because of 

 their advantages in soil, good roads, level land, etc. 



Air drainage of any piece of land always is much more 

 important than its exposure. Conditions on a northern or 

 eastern slope will delay blossoming-time a few days; but if 

 there is no lower-lying land into which the frosty air of spring 

 nights can drain, blossoms will freeze every year or two. For 

 this reason, certain tracts of land otherwise valuable are nearly 

 worthless for fruit; and to plant an orchard on them invites 

 failure, or at least an immense amount of work in fighting 

 frost every year. You would better protect your trees against 

 the frost for all time when you plant them. 



Get definite information about frost, if possible. During 

 blooming-time in the spring before you plant trees, put ther- 

 mometers a few feet from the ground, on stakes, one down in 

 the lowest pocket on your place, another a little higher up, 

 and still others at every twenty or thirty feet rise all the way 

 up the slope. By watching these thermometers carefully every 

 hour or two during a couple of nights when frost threatens, 

 you will get all the information needed, and know the strips 

 of land to avoid because of frost. Where such a test cannot 

 be made, carefully observe the lay of the land before planting 

 any trees. 



The relation of windbreaks to frost damage is mixed. Many 

 times they prevent freezing, but they sometimes are the direct 

 cause of it. For this purpose we can class a strip of woods as 

 a windbreak. The flow of air-currents must be studied to 

 understand the situation. When cold air flows from higher 

 land on a still night, and strikes a thick windbreak, it rises over 

 the tree tops and flows on to the middle of the orchard before 

 coming down among the fruit trees. This will cause a strip 

 several rods wide in the lee of the break to become badly 

 frozen, because here there will be a dead-air space. The break 

 forms a pocket of still air which is exactly like the frost trap 

 formed by the hills in the bottom down below. 



If the break had been thinner, really "breaking" the force 

 of the wind, and not altogether stopping its motion, there 

 would have been no frost alongside of it, while the decided 

 benefit of deflecting the cold air over the top of the orchard 

 trees would be as great as ever. See that a piece of woods 

 next to your orchard does not subject some of your trees to 

 frost injury. 



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