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Using supplemental heat source for frost protection


WestCoastGal

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Question about using supplemental heating for frost/freeze protection on your palms or plants. This is our first year with the yard being fully landscaped and haven't had to worry about it before now.

The palms we planted in our yard are cold hardy for our area (Zone 9b, Sunset 14) so not concerned about them during this upcoming cold spell here in the SF bay area. However to complement the tropical look of our palms we did plant out some more frost tender plants this past year like Strelitzia reginae (orange birds of paradise, cold hardy range 25-30?) which have been looking great in bloom and near bloom and I really hate to see them damaged at this point. Picked up a few commercial medium-weight frost blankets (6-8 degrees supposedly) to use this year; but if we are suppose to hit 25-ish or lower this year, thought maybe a plan for some extra heating might be required.

Does anyone use the sprays? Worth it or not? Our days can get to the 50s-60s, and wondering if the plant is able to breathe well enough during the warmer days.

How effective are Christmas light stands under the frost blankets? I thought I would put them on a timer and lay them on the ground. Do you use C9s or mini lights (non-LEDs)?

If I go the lightbulb route, I thought I might put them in a terra cotta saucer with inverted terra cotta pot on top (pot's bottom hole would then be on top for ventilation) thinking the pot would help hold and radiate the heat and keep the lightbulbs away from contact with the cloth (There are numerous examples of tea light candle & terra cotta pot heaters online--ceramic pots heaters--to heat a room) so something like that sounds in theory like this might work for the plants without the fire aspect. Do you think this would generate too much heat? Really curious to hear if anyone has done something like this with pottery and a light bulb or light strand before.

Zone 9b (formerly listed as Zone 9a); Sunset 14

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Debbie, From what I have read about the sprays, it is a waste of time. In my greenhouse I use a tabletop patio heater that runs off propane when temps dip close to freezing. Friends have used the larger version outside and have had good results. for some small palms I wanted to protect at my Mom's house (without a lot of time to do it) I pounded in some stakes around the palms and screwed in cardboard sheets directly above them hoping it would keep the cold from dropping straight down on them, kind of like having canopy. Hope this helps. Perry

Perry Glenn

SLO Palms

(805) 550-2708

http://www.slopalms.com

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Perry is right, the sprays are snake oil, total waste of money, don't bother. The large patio heaters are great, and they're what I count on for my insurance policy against a century freeze, but for a regular radiational freeze that you can expect every Winter in Gilroy, you really only need passive protection, i.e, no heat source, just the right kind of cover. I am not fond of the frost floating row cover. I've used that on my citrus only to see damage at 31F because the blanket super cools and gets ice cold (15-20F) even at 32-34F and will freeze whatever part of the plant comes into contact with the frost floating row cover. In other words, the stuff really sucks, it's only good if you use scaffolding that guarantees to not make any contact with the plant. And who wants to have to do all that work.

The best passive protection is silver reflective bubble wrap called Reflectix insulation. It's essentially bubble wrap coated with a radiant barrier on each side. It insulates AND it acts as a radiation barrier, preventing your plants from radiating away their heat to the night sky. Plant tissue can be in contact with it and won't get burned. For small seedlings I make a cylinder out of it and tape a top on it. It's quick, easy and super efficient. The bonus is that you can open the cylinder during the day and it will actually amplify the light the plant is exposed to, a useful thing in the Winter. On larger palms, you can just put the wrap in a plane above the palm as opposed to wrapping it.

BTW, this is the stuff you can use to wrap a more tender larger palm, giving you just about a full zone of protection.

Edit: Here's the link: http://www.reflectixinc.com/basepage.asp?Page=Double+Reflective+Insulation&pageIndex=622 each side reflects 94% so that will act almost as a 100% barrier. (6% of 6% makes it through, so more than 99% total reflection.)

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I've tried all the methods... sprays, frost blankets, heaters, xmas lights, etc.

The only thing that will work really is heaters and more heaters. Orange birds of paradise will do fine without anything, as it does in Rocklin which is 9B also.

Frost blankets, yes... and layer them on GOOD. Wrap like crazy. Go to http://www.americannettings.com/ and stock up on huge rolls -- high quality and it protects well. If it's around 28-29 for a short period of time, the blankets work well if they are covering well, but beyond that you'll need heat.

Large outdoor heaters will run all night costing about $14 per tank per night. But if you only got a couple of nights, it will keep everything from getting burnt. Other things that work, go get some huge plastic square sheets from home depot, drape it over whatever you want to protect, and put a small electric heater in there. WORKS GOOD surprisingly and I've kept my Kings green with this method before on those tough nights. ($1.50 per night vs $14 so much cheaper).

In Sacramento we're going to get bit hard this year. Jan 2007 was 29 22 24 24 26 28 29 for us which really did damage, but this year is forecasted 31 26 26 31 23 24 26 27.. It's one thing to have a 26 once in a while, but it's the duration of nights that really does the plants in. Oh well.

Edited by enigma99
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Perry is right, the sprays are snake oil, total waste of money, don't bother. The large patio heaters are great, and they're what I count on for my insurance policy against a century freeze, but for a regular radiational freeze that you can expect every Winter in Gilroy, you really only need passive protection, i.e, no heat source, just the right kind of cover. I am not fond of the frost floating row cover. I've used that on my citrus only to see damage at 31F because the blanket super cools and gets ice cold (15-20F) even at 32-34F and will freeze whatever part of the plant comes into contact with the frost floating row cover. In other words, the stuff really sucks, it's only good if you use scaffolding that guarantees to not make any contact with the plant. And who wants to have to do all that work.

The best passive protection is silver reflective bubble wrap called Reflectix insulation. It's essentially bubble wrap coated with a radiant barrier on each side. It insulates AND it acts as a radiation barrier, preventing your plants from radiating away their heat to the night sky. Plant tissue can be in contact with it and won't get burned. For small seedlings I make a cylinder out of it and tape a top on it. It's quick, easy and super efficient. The bonus is that you can open the cylinder during the day and it will actually amplify the light the plant is exposed to, a useful thing in the Winter. On larger palms, you can just put the wrap in a plane above the palm as opposed to wrapping it.

BTW, this is the stuff you can use to wrap a more tender larger palm, giving you just about a full zone of protection.

Edit: Here's the link: http://www.reflectixinc.com/basepage.asp?Page=Double+Reflective+Insulation&pageIndex=622 each side reflects 94% so that will act almost as a 100% barrier. (6% of 6% makes it through, so more than 99% total reflection.)

Oh nice... and I wish I had some on hand already:(

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Got in a few hours ago from covering the plants with the Dewitt Nsulate I had bought yesterday (4 pkgs of 10' x 12'). When I came to Calif I thought I had left midwest temps behind. Sure felt cold already and it was only in the low 40s when we were out. Thanks for all of your replies. Expecting it to drop below freezing in the early hours.

We didn't use the spray I had bought, based on your recommendations, and will return that tomorrow. Due to my late prep for frost/freezing temps (not sure where my mind was this year) really didn't have time to try to pick up anything else. I haven't seen the reflective bubble wrap before. Will look for it though to try out. I'll probably run to Target for some lights tomorrow since the temps could get down to 25 in the next day or two and I'm kind of out of options at this point for a heat source. The majority of our holiday lights now are LEDs so feel kind of reluctant to buying incandescents but at least they are fairly inexpensive.

I'll let you know in a week or two how we made out on the plants we covered. Everything was in ground and spread around the yard so not really easy to use propane heaters to get the coverage (and we don't own any to use). We covered 8 Strelitzia reginae (the most expensive of the lot and I just didn't want to take a chance of damage if I could help it), 1 Philodendrum sellum var Hope and 1 P sellum var Showboat. Had I enough covering material I would have loved to have covered our SunPatiens as well. They have been looking so nice and tropical and did super well in our heat this past summer. Our bamboo (bambusa textilis var gracillis) and all of our palms (butias, mules, trachy, sabal, C. humilis) and sago should all be fine. So happy we didn't have to bother with those. The little C. microspadix palms we bought at a palm society auction (from Dick Douglas' seeds), I'm sure would be fine outdoors but hubby made me bring them inside while he insulated our water pipes. We'll see how things do this year and then work out a plan for next year so we'll be ready. Definitely on the list is an upgraded weather station.

Zone 9b (formerly listed as Zone 9a); Sunset 14

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Thought I would report in. Just checked yard. Temp is now in upper 40s, expecting high of 51. A nearby local WUnderground station registered 27 last night for my area. The expected low for tonight is projected to be anywhere from 23, 26, 27 or 25 depending on the service (Intellicast, Accuweather, WUnderground BestForecast as source, WUnderground NWS as source). Similar temps throughout the week. Intellicast is the most depressing for the week with 23, 26, 29, 22, 23 and 25 but since we were several degrees above what they projected for last night I'm mentally ignoring theirs which are more 9a than 9b temps. We were around freezing around midnight and didn't get above until after 8 am, so cold night.

I went around and opened vent holes at "top sealed" covers and vent holes at two opposite "side sealed" covers where we did more of a tented covering to prevent overheating the plants under the NSulate. Had to get creative how we wrapped depending on height of plants. I'll "clothes pin" the covers back up late this afternoon. We tried to anchored covers with stones at the bottom when we could but not all had cover all the way to the ground so had cold air at ground level. interesting to see how those plants fare down the road. I don't plan to uncover plants at all during this week or two of really cold weather and the NSulate is suppose to be ok to leave on so we'll consider this a test. I did notice that the plants in the morning sun had some warm air trappped inside already so glad I established the vent holes.

Exposed Canna and SunPatiens under the canopy of our mature mules actually looked decent and barely touched. Those in more open locations and under our Trachy, not so good looking. The SunPatiens there I have no doubt are goners. Next year I will plan to cover and try to get full year growth from them. They were planted late summer as the yard was being completed and we didn't have much choice of color at that point. We were told to expect to lose them during the winter so planned to replace come spring anyway so no big loss. Good learning experience though on what to expect.

Is anyone else using frost covers during this cold spell?

Zone 9b (formerly listed as Zone 9a); Sunset 14

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Enigma, thanks for the link to the place in WA. Not bad prices and the cloth sizes were larger than what my garden center carried which would mean full to the ground coverage. The 12' length was a bit tight on two of my beds so their 25' would take care of that too. I'll keep them in mind for next year. Thanks.

Zone 9b (formerly listed as Zone 9a); Sunset 14

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Axel, sounds like you are describing a similar thing that I am using this year. I am using thermal foam underlayment for hardwood floors. Reflective on 1 side and about 3 mL thick foam. I can wrap it like a cylinder and use binder clips on the top to close it up. Another advantage is it is waterproof in case we get some wacko sleet storm or something like that. I posted pics on another thread

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Oh yeah, a few hot hands glove warmers near the growth point can help. Or, just concede that your out of zone plants will never exceed 10 feet tall and use spring gardener gable greenhouse. That's what I do. They go over my zone 10 plants. I have heliconias, alpinias, monstera, and cocos still growing in Dec 9a.

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Tropicdoc, wow heliconias and monstera in 9a. Impressed with your efforts. Both plants I would love to have growing outside in the ground.

Turned off the c9s hubby draped under and around his dwarf orange around 11 am. The leaves were curling last night before doing anything but actually look better this morning. Well see. No covering.

Sad, sad site in my backyard with the SunPatiens. All were collapsed and down on the ground, blackish looking. Knew this would happen but actually hadn't seen plants killed by cold before. I can tell my Canna intrigue which were so beautiful in bloom the other day will meet the same fate, just take a bit longer. Really wish I had acted sooner and picked up enough frost cloth to cover both of these. Don't know if they would have survived or not but feel bad seeing them today having done nothing. I know the canna will come back later in the year. Does anyone cover their canna?

While I feel bad about the plants, I can't imagine how badly I would feel if any palms met a similar fate. I'll drive around our area in a few days and go palm hunting to see how some of the more tender ones faired. Sure the queens will be affected by these lows and brown up and I'm not expecting a triple dypsis decipiens someone planted near their garage to be looking too well. Last year it got burned on the street-facing side and looked crappy in the summer but now it's had another year. Curious if they tried protecting them somehow this year.

Zone 9b (formerly listed as Zone 9a); Sunset 14

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We had HEAVY winter -wonderland- looking frost here in my neighborhood. Everyone's centipedegrass lawn is bright orange now. The queens in my neighborhood are absolutely unblemished. Queens are pretty tough. I highly recommend the spring gardener greenhouses. they are easy to put up and you just leave them up over plantings for your frost dates then take them down to enjoy your tropical wonderland during the spring, summer, and fall. And don't worry about the cannas... they are hard to kill. I mowed mine down, sprayed round up, let them freeze, and they are still trying to come up right now. I don't like them because we have leaf rollers that make them look terrible.

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My dad has an interesting miser heating device that he sets on the living room table that actually heats the whole room. It's a series of terra cotta pots, about 4, nested inside each other, bolted together through the bottom drain hole, and set up side down over 3 small tea light candles. The pots trap the heat and radiate it outward. It's very cheap to run.

Matt Bradford

"Manambe Lavaka"

Spring Valley, CA (8.5 miles inland from San Diego Bay)

10B on the hill (635 ft. elevation)

9B in the canyon (520 ft. elevation)

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