FROST DAMAGE TO ORCHARDS 



Orchard heating has been brought to a thoroughly efficient 

 state during the last few years, in Colorado and the Pacific 

 coast fruit-belts. It is a recognized feature of orchard culture 

 there, and is included in plans of work to be done on the orchards 

 just the same as are pruning and spraying. 



Certain situations here and there throughout the country 

 are so exceptionally favorable for fruit in other ways that 

 planting in them is advisable, even though the situation is 

 known to be frosty; or an orchard may be already located 

 where blossoms are often frozen; or once or twice in a lifetime 

 an exceptionally heavy frost may in blossoming-time visit an 

 orchard that is safe all other years. In such cases artificial 

 heating will save a great deal more money than it costs. 



Sometime along in April or May there will be a few days 

 of warm weather, with south winds and showers that will 

 start buds and bloom. Then, in a few hours, the wind will 

 shift to the north or west and blow the clouds away. A clear 

 night and a bright morning will follow, but this is just when 

 to look for the worst frosts. Have several thermometers here 

 and there in the orchard and near your house, about six feet 

 from the ground. Be sure your thermometers register cor- 

 rectly some don't. When danger threatens, watch the ther- 

 mometers carefully, especially from midnight till sunrise. 

 Start frost fighting while the thermometers read a couple of 

 degrees above the danger point. 



The Irishman said it wasn't the fall that hurt him, but 

 hitting the ground. So, it is not the freezing so much as the 

 quick thawing afterward which causes the damage to blos- 

 soms. If we can get something to prevent this quick warming 

 up, and make our frozen flowers thaw out gradually, we can 

 reduce the final damage 75 per cent. Clouds will do this, and so 

 will artificial clouds smoke for instance and smoke is just the 

 thing wanted for other reasons. 



Every one has noticed that the weather never gets very 

 cold when the sky is overcast with clouds. We might say safely 

 that frost never comes when there are low, thick clouds. Ob- 

 servation of this fact led orchardists long ago to adopt smudg- 

 ing as a frost preventive. The smoke makes a blanket 

 which shuts out colder air from above during the night, then 

 shields frost-bitten blossoms from the sun's rays in the morn- 

 ing, and allows time to warm up slowly. 



Some growers have ready piles of wet brush, straw and 

 leaves about the edges and throughout the orchard where 

 the fires will not harm the trees. Sometimes oil is poured on 

 these materials, but they should be kept as full of water as they 

 can be and yet burn. When the temperature goes down near 

 the danger point these piles are lighted. The moisture in the 

 fuel is valuable in three ways by increasing the volume of 

 smoke, which covers the orchard, by loading the atmosphere 

 with water, thus lowering the danger point, and by making 

 the fuel burn more slowly and last longer. 



Sometimes, when the frost danger is slight, a burning pile 

 of wet straw on a sled or wagon hauled here and there through 



