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Frost Damage Prevention Ideas?

Posted by shadetreetim Chandler AZ (My Page) on
Tue, Dec 11, 07 at 16:58

It is getting to be that time of year that we all need to be concerned about protecting our plants from frost damage.
In fact Dave the Garden Guy on TV said that tomorrow night
will bring frost to some areas of Phoenix.
What are all of you out there doing to protect your plants?
Any comments on the pros & cons of any and all methods of frost protection would be most appreciated.
Any one ever use a outdoor propane area heater placed underneath a tree for protection? Seems like it may be a good idea, but the best laid plans.... do not always work out as planned. In addition to my established plants,
I have newly planted jacaranda trees (3), a HG orcid tree, and 20 trumpet vines that I am concerned about.
Any and all comments, ideas, proven methods of preventing frost damage would be greatly appreciated.
Thanks in advance for all help.

Follow-Up Postings:

RE: Frost Damage Prevention Ideas?

I'll share my little invention that I use in mu citrus. I start with a jar candle, the little ones that are on

restaurant tables sometimes. The one's I use are about 2 1/2 inches across and 2 1/2 inches tall.
Next I take a 1 pound coffee can with one end out, the regular way you open a coffee can. Then I punch several

holes in the sides. I'd say about 6 near the top and 6 two thirds of the way down. This is with the open end as

the bottom so it can sit over the candle.
I set these out, with a little stick, maybe the size of a pencil, under one side, so that the can is tipped.

This lets air into the can for the candle.
The cans do a couple of things. First, when it's 30 degrees out, the candle wax will be so cold that the wick

will burn a tunnel right down through the candle and most of the wax won't burn. So the can keeps enough heat

in that the wax can melt and the candle burns the way it should. Next they act as little radiators. The idea

here is to heat a lot of air just a little. The heat from a candle by it's self would all just go straight up

and not help the tree. They also keep the candle from blowing out in a light breeze.
I do this with about 80 candles for 100 citrus trees. Of course being out at 2:00 in the morning, freezing my

fingers, lighting candles, is not a lot of fun, but it is a rather pretty sight.
Be careful for fire hazzard.
Do not place on or near mulch, branches, or other flammables. Clear a spot down to bare soil so that they are

clear of any material that can burn.
Do NOT put these directly under the tree as that will be to much head and will "burn" them. I place them 3 to 4

feet out away from the tree.
If you do this, you should monitor them closely. I will put a movie on, make hot tea, set a timer, and check

them once per hour after I have them set.
I got all my citrus through last years hard freeze. We had 3 days of more than 12 hours of below freezing temps

with a low of 10! one day and 2 more days with lows of 12. Nasty cold for citrus. The limes didn't fruit this

year. The trees are ok though. Everything else had fruit (see my page for a list of everything we have.
I also run irrigation water while doing this. the heat from the water helps too. Start irrigation water early,

several hours before the temp drops below freezing, to build heat in that area. If you wait until it starts to

freeze, it's to late. I start candles about 2 hours or more before temps drop below freezing.

Frost Warning Info

I've been trying to find out when a frost will occur in Phoenix, but have found no sources of information on the internet. What channel is Dave the garden guy on and when? Any other sources?

RE: Frost Damage Prevention Ideas?

I move mine to a covered patio or the garage. The ones I cant move get covered with old flannel sheets.

For smaller seedlings etc. I have 3 big iceboxes and I put them all in there and shut the lids at night and just open them up during the day. You can even water them in there-just pull the drainage plug out so the icebox can drain :)
I used to do this with my seedlings in early spring when I lived in a zone 3b and it has never failed... It a good way for lazy people like me who don't want to drag seedlings pots in and out of the house!

RE: Frost Damage Prevention Ideas?

For great information on protecting your landscape plants from frosty or freezing temperatures, take a look at the publication issued by the University of Arizona Cooperative Extension office.

It also has the average frost dates for the metro Phoenix area.

Here is a link that might be useful: Frost Damage Prevention

RE: Frost Damage Prevention Ideas?

Thanks for the responses. Softmentor's candle idea is very interesting.Where can a person buy the candles and cans that you recommend to use? I am not a coffe drinker so I don't have a supply of empty cans available. Any ideas out there?
Dave the Garden Guy has a website that lists his radio and TV times. The site is at
As always, great info from aztreelvr.
Thank you all for your help.
I covered my bougevillas and hibuscus last night with burlap. I had no damage to these plants. But the newly planted 24" box Jacaranda tree's had a little bit of frost burn on the tips. I don't know how cold it got here last night; but at 6:20 AM it was 39 degrees at my house. Dobson/Warner area. The burlap covers on the south & west facing plants had frost on the burlap.
Any other ideas will be appreciated.
Where are all of you located at and what nightime temps are you getting?

RE: Frost Damage Prevention Ideas?

For my tomatoes, peppers and squash, I built a hoop house as I grow in containers. It is approximately 12X12X6 at the eaves and 8 at the center. I cover about the 15th of Nov and go to about the 1st of March depending on the weather forecast. For my out door plants; rubber tree, butter fly bush, gardenia, and several others, I normally cover in the evening and my wife takes the down during the day. I did loose one of my gardenias last year when the wind blew the cover off part of the wrap. I have seen people put sheet on the plant in Nov and take them off the 1st of march and wonder why they look so bad. When it warms up take the cover off and only cover it when it is predicted to be less than 40 in the night. Most plant will be able to take a couple of hours at 35 with out much problem.

RE: Frost Damage Prevention Ideas?

The temps haven't gone low enough yet to do any damage, so don't pat yourself on the back quite yet, shadetreetim. :) When the temps dip below 30'ish is when you will start to have problems with the frost sensitive plants. Last year when we had a couple of different frosts, and temps were in the 20's, was when people really had problems protecting plants. All my lantana, hibiscus, sweet potato vines, and a couple of others died to the ground, but all of them came back from the roots and grew even bigger than the previous year. I even had dieback of hibiscus in nursery pots, and those came back too. The only things I have ever truly lost were a ficus tree, that I shouldn't have had in the first place, and a pink bower vine, that was just in the wrong spot. Sometimes I cover and sometimes I don't, and I always have the same dieback and the same regrowth in Spring. You just have to live with the ugly dead foliage until it warms up.

If you HAVE to protect, you can group Christmas lights around the base of plants and also cover with a sheet, making sure the sheet goes all the way to the ground. Stakes or rocks piled on the base of the sheet to keep it on the ground are a good ides. Turn on the lights before bed, and then remove the sheets and turn off the lights when the temps rise in the a.m. Never leave the sheets on during the day or you will cook the plants or force them to start growing because they think it is Spring, and then they are toast when it freezes next.

Anywhoo, good luck, make your own choices as to what feels right, and don't be afraid to have to replace a plant or three come Spring. Also never prune the dead foliage off before the last possible frost date. It protects the rest of the plant from more damage if it freezes again.

RE: Frost Damage Prevention Ideas?

I bought my first jar candles at Costco some while back but don't see them there any more. I bought a few more this year at the dollar store and I buy wax and wick to refill my jars, much cheaper than buying new jar candles.
For cans, check out the size of a 1 pound coffee can in the store, you can buy anything that uses the similar size can. I think some juices, like grapefruit juice, come in that size. Be cautious though of cans that have a plastic coating on the inside as the plastic will burn and the fumes are toxic. If you have friends who work in an office that has a coffee pot you could ask them to save cans for you. Also Mom's with kids in school often save things for crafts and might be a place to get help finding some.
The one pound coffee can is just about the perfect size though, to use with a 2 1/2" wide by 2 1/2" tall jar candle though, so try to find cans about that size. That size jar candle should give you about 2 or 3 nights depending on how long you need to keep them going.
Remember, frost will last a little past sunrise, so don't put them out to quickly.
Also to blow them out, I use a cardboard or piece of wood about the size of a pizza box and just fan them out. They are too hot to pick up and that's too much bending over otherwise.

RE: Frost Damage Prevention Ideas?

I use Agribon 50 fabric that I cover trees with to reach the ground. Under this canopy I place a single heat lamp (250 watt).

Works on my mango trees, guavas, avocados, royal palms, white sapote, etc. Most citrus is pretty tough in Phoenix, even lemons and limes here. I didn't really have a problem with them last year when we had the 20-year killer freeze. I didn't even protect my key lime tree. It was damaged but came right back. No problem. I never protect my citrus.

I bought the roll of Agribon fabric from an Agriculture supply shop and they shipped it to my house. Good stuff and not too heavy so great for using to cover plants.

Tonight, 'mummied' certain plants in my yard for the impending frost. Yahoo weather will tell you when a frost warning is issued for the Phoenix/Tucson area etc.

I wasn't too worried last night because it was windy and that helps keep frost at bay. I didn't cover anything. Tonight is a different story. This is my first protection effort of the season.

Another option is to just use a powerful fan on the foliage, but I prefer the cover and supplying heat.

Good luck, all.

RE: Frost Damage Prevention Ideas?

ok so I'm starting to get some things ready to protect my tropical plants/trees this winter. I'll be buying a huge frost cloth next week on eBay. I also got some C9 Christmas lights today and a couple of floodlights (90watt bulbs).

My question is, will one floodlight with a 90watt halogen bulb be enough to keep my Hong Kong Orchid tree(10ft tall) warm + the frost cloth? or should I use two floodlights?

RE: Frost Damage Prevention Ideas?

  • Posted by AJBB none (My Page) on
    Thu, Nov 24, 11 at 12:11

You're probably going to need to drape your orchid tree with some Christmas lights as well, if the goal is to also protect the growth in the upper branches. Think of it as an alternative Christmas tree.

RE: Frost Damage Prevention Ideas?

yeah I was thinking of wrapping the main trunk with lights. I might as well put some around the branches too. thanks!

RE: Frost Damage Prevention Ideas?

Anybody know how this thread on **frost** prevention got here in the middle of a heat wave?!

RE: Frost Damage Prevention Ideas?

Spam ... the spammer bumps the thread up, GW deletes the spam, the thread stays bumped.

But dealing with frost sounds like a lovely problem.

RE: Frost Damage Prevention Ideas?

Yes, frost does sound good right about now!

RE: Frost Damage Prevention Ideas?

I don't have any tips on frost prevention, but I want to say that I've heard Dave the Garden Guy on TV before and thought some of his recommendations were "questionable." I can't give you an exact example right now, but he wouldn't be my first resource for reliable gardening information right now. No offense intended.

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