Some season extending measures do not do enough to extend the season.
And additional problem is night sky radiation. Some of you will notice that clear nights are cold nights, even with out a problem with frost pooling it is possible for more radiation to leave the tissues of a plant than comes in to them, in that case the tissues will freeze and a raised bed does nothing to prevent it (and may make it worse by holding the plant further away from the radiant heat from the ground.
I always have said I won't plant my tender plants outside until AFTER the full moon in June here in Michigan as the full moon on a clear night will always bring a frost..we had a couple summers where we had a frost each month all summer long cause of the full moons..and that sucks bigtime.
"A Frost Diversion Arc deflects frost. It is on a hill, with the highest point at the top and sides going around the plants that need protection. As cold air drains down the hill it flows to either side of the arc. When it reaches the bottom of the hill it pushes warmer air up into the arc to those plants that need it most. If the slop is northerly facing ((Aussie book, flip for norther hemisphere)) the arc can double up as a sun trap. Sun traps increase and store heat in the soil, water and structures with a high thermal mass. This also helps prevent frost." Pg112
I don't think of it as water, more like molasses.
also like mentioned, cold clear nights after a storm has passed is the worst. everything gets frozen solid. except my peas too haha.
Rob S. aka Blitz wrote:
Im curious as to what altitude you all are at that you get this reversal?
180' here above and I see it on a daily basis, it's a great morning show to watch over chai, coffee or tea
The clear skies can suck heat so quickly out of the water that it freezes, even though the surrounding air might remain @ 35°.
Similar experiments have shown that on a 30° F night, two dishes of water, side by side, one at 33°, the other at 38°, the warmer dish will freeze first. The more rapid temperature change needed to "equalize" the warmer dish is what causes this phenonoma.
This is how I setup our farmstead. Our neighbors down in the valley get frosts later in the spring and earlier in the fall than us because the frost settles down there. I setup all of our gardens and terraces so the cold air drains down and away from us. It makes a very big difference. This gains us weeks of frost free time on either end of the growing season for things like pumpkins, tomatoes, etc.
Unfortunately we have much deeper snow cover due to our altitude so we get snow up here much earlier and it lasts much later than for pastures down in the valley. This means our grasses, our fields, open up later in the spring. I combat this by changing our albedo by spreading wood ash using the wind. The wood ash darkens our snow fields and causes the sun to melt them sooner. Timing is critical as is wind direction. Think Local Warming!
Sugar Mountain Farm
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