Trial Run

Going to be a bit cold in the desert tonight...lows in the upper 30's f.
Hey its cold for us! Have a new set up for frost protection on the benches. Lead pipe to hold up the cloth (planket) and to string some lights up. Multi colored 35 watt bulbs from COSTCO. Put boards on the cement so the pots on the ground would have a little insulation.

I would think that the cement would hold the warm better than wood. Bet it looks like a party tent at night!

Do what the growers do, and spray your trees with water.

Bonsai Nut said:

Do what the growers do, and spray your trees with water.

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Doesn't spraying just help to insulate temperatures from not going below 32 degrees? I wouldn't expect it to effect temperatures in the high 30s. Putting the trees on the ground though with the warm concrete might help though.

Lars Grimm said:

Doesn't spraying just help to insulate temperatures from not going below 32 degrees? I wouldn't expect it to effect temperatures in the high 30s. Putting the trees on the ground though with the warm concrete might help though.

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Oh, LOL I didn't see the high 30's I don't do anything to my trees in the high 30's. My citrus - tropicals - bougies - they don't care. They only care if it freezes.

AZbonsai said:

Going to be a bit cold in the desert tonight...lows in the upper 30's f.
Hey its cold for us! Have a new set up for frost protection on the benches. Lead pipe to hold up the cloth (planket) and to string some lights up. Multi colored 35 watt bulbs from COSTCO. Put boards on the cement so the pots on the ground would have a little insulation.
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Gotta love the overkill with folks who don't get much winter. This tarp covering and light bulb arrangement isn't going to do a lot and is mostly unnecessary for many of the trees underneath it if the temps are only going into the upper 30s'

ALL of the evergreens don't need ANY protection in that situation, neither do any of the native collected trees. Only things that MIGHT need some shelter are true tropicals.

Things only get dicey for the conifers and broad leaved collected trees when temps approach 25 degrees and remain there long enough to freeze soil significantly. It doesn't sound like you're going to be anywhere near that.

FWIW, as mentioned before, water is your friend in short cold snaps like this, as are "heat sinks" like concrete driveways. Get the plants OFF those benches and onto the ground--freezing is accelerated when things are exposed on all sides by freezing air--which is why there are warning signs about "bridge surfaces freezes before roadway."

Well watered root masses are a must. Spraying water on leaves can also protect them from short dips into the 30-25 range for a short period.

As said before, water acts as an insulator on roots and leaves, as the water on the surface has to freeze first, then the water in the leaves underneath. Freezing water also gives up a bit of heat as it freezes. Watering roots is a very good way to protect bonsai on benches in shallow freezes, since it does the same thing for roots as it does for leaves--acts as an "insulator" against the cold for a while.

Notice the thread title people. Trial Run. Just wanted to get it set up before we actually have a hard freeze.....if we ever do! And yes I did water before I put the tarp on you can see the puddle in the picture. And actually, this type of cover does work for the amount of freeze we experience here. We might go 1 or 2 days with freezing temps at night and mild temps during the day. So we need something that we can take off during the day. As far as the lights are concerned, your right, they do little for very hard freezes, however, for the duration of our freeze time they give just enough heat to boost the temps up a couple of degrees in a set up like this and that is about all we need. I pilled all the plants under there just to see how many I could actually fit. I realize the junipers do not need to go in there....actually I have a few sitting out in the picture. Judy you may be right about the cement holding the heat a little better. I may do that. Thanks for the replies! If I ever move up north now I know what I need to do. I do not think that is going to happen anytime soon.... today's temps will be in the 70's. Great for a round of golf or tinkering with plants.

It was the Phoenix Lights in my backyard this morning.

AZbonsai said:

Notice the thread title people. Trial Run. Just wanted to get it set up before we actually have a hard freeze.....if we ever do! And yes I did water before I put the tarp on you can see the puddle in the picture. And actually, this type of cover does work for the amount of freeze we experience here. We might go 1 or 2 days with freezing temps at night and mild temps during the day. So we need something that we can take off during the day. As far as the lights are concerned, your right, they do little for very hard freezes, however, for the duration of our freeze time they give just enough heat to boost the temps up a couple of degrees in a set up like this and that is about all we need. I pilled all the plants under there just to see how many I could actually fit. I realize the junipers do not need to go in there....actually I have a few sitting out in the picture. Judy you may be right about the cement holding the heat a little better. I may do that. Thanks for the replies! If I ever move up north now I know what I need to do. I do not think that is going to happen anytime soon.... today's temps will be in the 70's. Great for a round of golf or tinkering with plants.

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You said nothing about "hard freeze" you said "frost protection." Those are two different things with different requirements for protection.

Short shallow freezes at night followed by mild days aren't a concern for much of anything, except tropical. Placing plants on the ground behind a fence or other solid barrier will probably be enough for a lot of trees. If daytime temperatures aren't forecast to get much above 4o or so for three or four days, there could be some cause for alarm, but in Phoenix, that's not usually a problem. I lived there for a while.

rockm said:

You said nothing about "hard freeze" you said "frost protection." Those are two different things with different requirements for protection.

Short shallow freezes at night followed by mild days aren't a concern for much of anything, except tropical. Placing plants on the ground behind a fence or other solid barrier will probably be enough for a lot of trees. If daytime temperatures aren't forecast to get much above 4o or so for three or four days, there could be some cause for alarm, but in Phoenix, that's not usually a problem. I lived there for a while.

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True enough.

I like to refer to an article on @Brent's site.
https://www.evergreengardenworks.com/frzekill.htm

I say read everything there until you remember it and buy some stuff. Brent is pure gold.

milehigh_7 said:

I like to refer to an article on @Brent's site.
https://www.evergreengardenworks.com/frzekill.htm

I say read everything there until you remember it and buy some stuff. Brent is pure gold.

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Great article. I like how he broke down the actual temperatures and what the plant goes through at those temps. Thanks Clyde I appreciate it!

I will say this... when it gets close to freezing it is the WIND I am worried about. To that end, your shade cloth would provide protection, as well as keep trees on the ground a little more insulated from drying out.

The cover I use is called a Planket. It comes in 3 different sizes. It is lightweight and breathable but it does block out the sun so if you have plants that are not dormant you have to take it off to let light in to them. It is good for frosts and light freezes that is why it is good to use in my part of AZ.