Saving our peach crop with mist

Grants Pass used to have a hard freeze problem mainly with apricots, which are the first fruit trees to bloom.  Our landscape management teacher told us to avoid growing apricots because we’d never get a crop here.   This year, it was peaches that were in danger of freezing their flowers off.

All this week, weather reports have shown a hard freeze coming Sunday morning after Saturday rain.  I have long seen on TV news how Florida orange growers deal with hard freezes, turning on sprinklers overnight to keep their flowers and fruit from freezing.  I decided to put my large mister made of PVC pipes, standing 6 feet tall with nine emitters on the pole, in the middle of my peach tree, which was in full bloom by Saturday, and turn it on overnight.   

People in my house were skeptical and thought of this as an experiment.  I knew it would work.  If it works in Florida, it will work anywhere, and it worked Sunday in my yard.

In 2000, our teacher told us that when liquid water turns to ice, it loses a lot of heat to its surroundings to make that phase change, just as water sucks in heat, cooling its surroundings, to make the phase change from liquid to vapor, something that can only happen over 41 degrees F.  Likewise, melting ice sucks heat and cools its surroundings when it changes to liquid, which we take advantage of to make homemade ice cream, salting the ice to melt the ice faster and freeze the ice cream mix as we stir it.  Ice is also highly insulative, so once the flowers were covered with ice, they didn’t freeze.

Every flower on that tree was still perfect.  Interestingly, I found that the mist spread a very long ways during the night.  I’d left a broom and standing dustpan about 50 feet north of the tree, leaning on a tent shed.  It was not only icy before the frost started to melt, it also had liquid water in the dustpan before the frost melted.

It was a freezing morning and it built up more ice as I took photos and then left the mister running when I went to play cribbage with a friend.  When I returned about an hour later, it was turned off and all the ice had melted.  The flowers look just like they did the day before.  The mister will stay in that tree until the danger of hard freezes passes.

 Published at GardenGrantsPass.blogspot.com.

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 Rycke Brown, Natural Gardener          541-955-9040           rycke@gardener.com