The OHGpC - One Heated Greenhouse per Culm - project...

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danjcla
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The OHGpC - One Heated Greenhouse per Culm - project...

Post by danjcla »

For the ultimate in Zone 6 winter culm luxury...

I was already planning on trying individual culm greenhouses next year, so the logical next step... heated individual posh culm greenhouses.

Any suggestions on what temperature range to aim for, and ideas if periodic rapid change in temp would be bad?

Thanks to the magic of eBay and Chinese ePackets, I think I can do it at around $10 per culm, I'd do maybe 4 culms:

$3 DC 12V Thermostat Temperature Controller Switch Board Red Digital Display + Case - eBay
$2 (half of an easily segment-able) Green 5M Waterproof 300 LED 5050 SMD Flexible LED Light Lamp Strip DC 12V - eBay
$5 8' long 1" dia clear plastic tube - Home Depot
(I'm a tinkerer so already have soldering iron, wire, etc.)

Plus some home-made steam-punk-looking enclosure for the individual LED temp readouts outside...

I need test to make sure the LED strip will put up enough heat to hit say at least 5F when it is -5F outside. I have everything but the temp controller on hand already, but I think an IR thermometer I have will suffice for testing... If not there is just actual 12v heating wire available on eBay, or a $8 104F self-regulating / self-limiting PTC heating element by itself might work, or this circuit, although having a panel of LED displays for the bamboo outside would be more nifty :-)

Although on second thought, I think I'l experiment with different methods; the PTC does have the advantage of way fewer points of failure.
$3-temperature-controller.jpg
$2-8ft-green-led-tape-for-heat.jpg
$5-8-ft-long-1-in-diameter-clear-tube.jpg
Alan_L
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Re: The OHGpC - One Heated Greenhouse per Culm - project...

Post by Alan_L »

I like your thought process, but there are questions. Don't know how many of them are valid, but here goes:

- How will you get the branches into these?
- Most of the leaves will be touching the tube, giving contact with the outside temps.
- (as you said) how much heat will these actually produce?
- Are they bright enough to trigger photosynthesis? I seem to remember reading about trees near street lights and how the almost round-the-clock light caused problems for them. Maybe I'm remembering wrong?
- With actual greenhouses, bigger is better for temperature regulation.
- These would provide wind protection at least (but wouldn't a tarp be easier?)
- Electronics and tubes lit by colorful LEDs -- how long before these "walk away" to decorate a bedroom?

Not trying to discourage you, just helping you to think it through. :)
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Re: The OHGpC - One Heated Greenhouse per Culm - project...

Post by dependable »

I agree with Alan's points. Also, if you do manage to wake up above ground growth when roots are still frozen/dormant, any remaining living culms will be desiccated and killed. I would wrap with burlap and see what has made it in the spring.

As for controllers, here is one that has its own temp sensor, you can set to keep things at temperature range you set. I use one with a heat blanket to keep homebrew fermentation vessels at optimum temps.

https://www.google.com/aclk?sa=L&ai=DCh ... CD8&adurl=

If you feel you need to do something extra for them, maybe a heat blanket or pad inside the burlap or tarp tent, set for 30 or 40*F. You want to keep them from further freeze damage, not wake them up prematurely.
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Re: The OHGpC - One Heated Greenhouse per Culm - project...

Post by needmore »

It has been many years since I learned the story and facts are blurry but a friend of mine sold bamboo to a doctor who lived in WY or MT, MT I think. He basically used a radiant floor heat system outdoors for bamboo - in stone I think not concrete, maybe even just ground/mulch. Then he had a removable enclosure that went over that.

Greenhouse folks sometimes use this heat method instead of those overhead blast heaters. My rental house has a radiant floor system that uses a 30 gallon water heater and circ pump. I think this might be only a bit expensive, the water heater and tubing are not too expensive, although it might be smart to use copper instead PEX around rhizomes - pump cost? Dunno, probably not much.

Why not circulate warm water through stone mulch and drop a temp greenhouse over them. More expensive than your method with out a doubt but it should work. I would not bother with this for your Phy atro planting but for a bed near a house in a marginal area...
Brad Salmon, zone 12B Kea'au, HI
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Re: The OHGpC - One Heated Greenhouse per Culm - project...

Post by stevelau1911 »

Looks like you have a tiny plant that will only get a bit larger next season, and at that size it would still keep getting bigger with complete top kill. You may be able to get away with opening a few white trash bags, and then covering it up with a couple of logs to top it off, save some leaf bags to give top insulation. Atrovaginata should handle zone 6well for half the winters anyways so i dont think you need a greenhouse, or a heater.
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Re: The OHGpC - One Heated Greenhouse per Culm - project...

Post by dependable »

The radiant heat tubes in root zone might be good in some applications, I will keep that in mind. Going to be hard to run across sidewalk in danjcla's case.

Are the northern boo growers giving bamboo a bad name with neighbors by using blue tarps and white trash bags to protect their boo in the winter? If it is in a high viability area, maybe better to winter wrap plants so they do not look like garbage. ;}
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Re: The OHGpC - One Heated Greenhouse per Culm - project...

Post by Tarzanus »

I was thinking about heatung up the bamboo in a unheated terrace. I have a water-water heating system that uses warm ground water (10°C) to heat up the boiler water up to 62C. It takes away some temperature to heat up the water and returns water at around 7°C back into the ground. I was thinking if I would use that returning water to heat up the concrete containers in which I would grow bamboo. I never went that far though. Perhaps one day...
danjcla
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Re: The OHGpC - One Heated Greenhouse per Culm - project...

Post by danjcla »

Thanks for all the feedback, keep it coming! :-)

New worry: Would any amount of heat (not light) on the culms (not roots) prevent dormancy? Or another way of putting this: Can I use a component that'd possibly keep at least part of the culm at 110F, or do I need to aim for more like 10F?

Q: How will you get the branches into these?
A: It will be placed over the shoot shortly after the shoot emerges. I did this last year to guide some shoots away from a small tree, and the 'boo seemed to be perfectly happy branching and leafing out inside the tube. I saw no indication the tube was causing any health problems for the leaves; I only took them off as for the training purpose they were no longer needed after the culm was full-grown. After I took it out the branches did move down and now look normal, but I'd be fine even if they stayed up, it'd be a nifty look. Specifically for this purpose the idea would be to put them over around half the culms each Spring, and leave them there until after the first Winter. So there would always be at least some culms with leaves to maximize the next upsizing cycle.

Q: Most of the leaves will be touching the tube, giving contact with the outside temps.
A: This is a great point! Unfortunately I can't find 8' T8 (1" diameter) tubes for a reasonable price locally (if you are near a Menard's you are in luck), but Home Depot has 4' T8 and 8' T12 (1.5" diameter), and actually I already have some leftover T8s from last year, so my current plan is to have the bottom 4' be in a double-wall configuration, and let the atro fend for itself above that. The partial double wall also solves the problem of a heating element that can get up to 113F (the small PTC one) being right up against the plant; I'll attach it to the outer wall near the bottom, and then convection should spread the heat up and around. Acrylic doesn't melt until 320F so I should be totally fine there.

Q: (as you said) how much heat will these actually produce?
A: For the LEDs - A highly BS-y calculation shows that to get from -5F to 5F in this very small area enclosed by a solid non-insulating surface requires on the order of .3 BTU / .1 Watts per Hour. Around 5% of LED output goes to heat, so I'd need 2 Watts of LEDs in the space. Two Meters of 5050 LEDs = 120 LEDs at .2W/LED = 24W. So in theory an order of magnitude to spare, which is good, because the space will not in fact be totally enclosed - don't want to suffocate the plant, and I'm guessing not that much air would filter up through soil. But I'd test all this stuff in real life this winter, as I'm not at all confident in my physics skills. Also your comment about not wanting to encourage photosynthesis is making me look more at non-luminous heating.

Q: Are they bright enough to trigger photosynthesis? I seem to remember reading about trees near street lights and how the almost round-the-clock light caused problems for them. Maybe I'm remembering wrong?
Q If you do manage to wake up above ground growth when roots are still frozen/dormant, any remaining living culms will be desiccated and killed.
A: I also looked into this, and my memory is that it was actually surprising how little issue round-the-clock light caused for plants. But bringing it out of dormancy would probably be more of an issue. I do have some lights on the 'boo all the time already - of higher wattage - and it seems fine. I choose green for aesthetic purposes, but it also turns out that green is the least likely color to trigger photosynthesis as most of it gets reflected by the green chlorophyl in the plant. But I don't want to chance this re: dormancy, so looking more into non-light-giving sources of heat now.

Q: Electronics and tubes lit by colorful LEDs -- how long before these "walk away" to decorate a bedroom?
A: I've had various lights and other stuff up for years, so far nothing has been stolen. I'm lucky to live in a very nice neighborhood on a very low-traffic street.

Q: With actual greenhouses, bigger is better for temperature regulation.
Q: These would provide wind protection at least (but wouldn't a tarp be easier?)
Q: I would wrap with burlap and see what has made it in the spring.
Q: Burlap or tarp tent
Q: White trash bags
A: This is on a public sidewalk where a tree used to be; a tarp or burlap would be too ugly, and the shape is really weird so I'd have to custom-make a larger double-walled enclosure, which I don't have skills / tools to do, and in any case the sheet acrylic I'd have to buy would be way more expensive as the shape would not be self-supporting like a cylinder so would have to be a lot thicker in addition to the larger surface area.

Q: As for controllers (link to google.com)
A: As far as I can tell the controller I link to has the same functionality, but is an order of magnitude less expensive. Or actually I guess I neglected to do a link... here it is, before I was able to find ~$3 with free shipping, that place seems to be out of stock, but even the current ones are under $5 with shipping. DC 12V Thermostat Temperature Controller Switch Board Digital Display + Case.

Q: Radiant floor heat
A: Problem is it needs to run on 12V DC landscape wiring; all the radiant floor heat cable I've been able to find runs of 120V or 240V household AC, except some for RVs and boats, but I've been unable to find that kind for sale in small quantity. Also since the main area the above-ground parts of the bamboo is mostly in at this point is small the roots are probably super-dense at this point, so I wouldn't want to try to bury anything in the soil, too much chance of harming the plant. I'm guessing heating the soil might also prevent dormancy, which someone else suggested might kill the plant, esp. I'm guessing if power gets cut by accident occasionally.

But if you can find a place that sells 12V DC boat flooring heating cable by the foot for cheap, I'd love you forever!
18-mini-ptc-heater-self-regulating-104F_1000_1000.jpg
Alan_L
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Re: The OHGpC - One Heated Greenhouse per Culm - project...

Post by Alan_L »

danjcla wrote:...I'm lucky to live in a very nice neighborhood on a very low-traffic street...
Your photos always fondly remind me of my visits to Cambridge. My preferred walking route between the hotel and the office was a block off Mass ave. Those cobbled sidewalks have plenty of character but are murder on luggage wheels. :)
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