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Heat mat or something else to keep plants alive in winter ?

Heat mat or something else to keep plants alive in winter ?


  #1  
Old 10-03-22, 04:07 PM
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Heat mat or something else to keep plants alive in winter ?

We are in Southern Oregon, zone 8b and like to overwinter canna, lemongrass, begonias and maybe something else. No greenhouse....but there is a concrete slab outside our guest house with roof overhang. 120V close by. I can build a frame about 3' x 3' x 12' and insulate floor, walls and top very well. These are corms and roots that do not need light or water....just a warm place to keep the roots from freezing. Some are in plastic pots with soil.

Heat mats with a stat are expensive. What about a metal drop light with a 100/200 watt bulb...and a plug that activates power when temp gets to 35 degrees and shuts off at 45 degrees ? How about a space heater or electric blanket, using same temp plug. ?

Any comments and suggestions are welcome.....
TIA
 
  #2  
Old 10-03-22, 04:14 PM
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If exposed to cold they will die, get them inside a conditioned basement or crawl space!
 
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Old 10-03-22, 04:53 PM
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They need light and heat. A 50-75 watt reflector flood would be effective.
I doubt heating the pot will be helpful.
 
  #4  
Old 10-03-22, 04:56 PM
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We're in zone 6b. We overwinter a dozen or more plants in the basement with grow lamps on a timer. As long as we remember to water them occasionally they do OK.
 
  #5  
Old 10-04-22, 05:46 AM
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Heat mats expensive??? I think we have different ideas of expensive. The last I bought were less than $20. They are inexpensive, safe and all the energy is released as heat. And most importantly the heat is released into the soil you want to keep warm and not wasted heating the air. Make sure to insulate the bottom of your enclosure. An inch of rigid foam can do wonders to preserve heat.

No, a light bulb will not be the best source of heat. Incandescent light bulbs are getting hard to find and have a short life. What is your plan B if the bulb burns out on a cold night? Also, a light bulb will warm the air in the top part of the enclosure, not the roots you want to keep warm.
 
  #6  
Old 10-04-22, 06:53 AM
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Thanks, PD. I will have 36 sq.ft. of floor space. AFAICT they are kinda small and I might need 5 or more. Can you send more info on size and pricing.....? I saw a 48inch x 21 inch with stat for $65.
 
  #7  
Old 10-04-22, 10:10 AM
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If heat mats are too expensive and you want heat a larger area... use a heater? They are available in a variety of sizes. Be mindful when heating your enclosure that you don't want it too warm if trying to force plants into dormancy. You only want to prevent freezing.
 
  #8  
Old 10-08-22, 02:41 PM
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Smile

CHANGE OF PLANS.......I have a wood shed with 120v inside. It has shelves. I would like to partition off two spaces about 30 " high x 42 " deep x 50 " wide......by using 4' x 8' rigid foam panels that are either 1 or 2 inches thick. I can use a space heater or metal backed drop light with a ThermoCube to keep the new spaces warm.

My problem is..... my feeble mind cannot come up with how many panels I need to encapsulate one shelf space.
Help....please
 
  #9  
Old 10-09-22, 06:19 AM
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Change your dimensions slightly and the math gets easier and you have less material wastage. If your enclosure is 48" wide instead of 50" will save a lot of material and you can make the depth 48" instead of 42" to gain extra space without having to consume any more material.

I use this heater and have it plugged into a thermostat. The only thing special about it is that it is low wattage, only 200w so it's great for keeping small spaces from freezing. And, it's not so hot when it runs that it can burn or cook the plants that are located close to the heater. It's also better than a light bulb because the fan distributes the heat throughout the enclosure.

Another option for heat is seed bed heating tape or wire. It's sold in long lengths like 50 feet. You can run it back and forth along the bottom of your enclosure and set the pots on top. The same can be done with heat mats. It will be great for keeping the soil warm and the heat will rise and protect the rest of the plants as well.

I don't like using light bulbs for many reasons. For one they burn out and you've lost your source of heat. Also, it's a very hot point source so you have to be careful to keep plants, foam and flammable material away. And, it produces light. Light can keep plants active and retard them from going dormant for winter. It also can affect flowering and growth as some varieties need a daily dark period.
 
  #10  
Old 10-09-22, 10:40 AM
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Thanks PD for your thoughts. Would you be kind enough to figure out how many 4x8 panels I need.....using your dimensions.....to fully encapsulate one space. TIA. PS: Who are you picking today....49ers or Panthers ?
 
  #11  
Old 10-13-22, 02:05 PM
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Hi everyone....I calculated each piece in square inches and divided by 144....and came up with 56 square feet to close in one space. So.....2 each of a 4 x 8 sheet of rigid foam will do it...and 8 sq feet left over.
How did I do ?

Now I know why this forum is called DO-IT-YOURSELF.

PD....Sorry about the 49ers clobbering the Panthers. But ex-coach Rhule walks away with $ 40 mil.
 
  #12  
Old 10-14-22, 12:27 PM
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It's not so much about the square inches because you need to consider wastage. You can draw it out. A rectangle 96" long x 48" wide. If you make all of your sides tops and bottoms 24" high by 48" long you can get four pieces out of a sheet of material without any waste. If you use other dimensions you may find you need more sheets to get the pieces you need and with increased waste.
 
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  #13  
Old 11-14-22, 09:37 AM
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Hi again.....after all that, I decided to dig a 2 foot deep trench in one of our box beds and overwinter the trimmed canna in there and cover back up with soil. A tarp will go over the trench to keep out rain. The begonias and lemongrass will go into the garage, after I cleared out some space. It is 20 degrees warmer than outside.
Thanks for your comments/help.
 
 

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