How much heat does a 400watt metal halide produce?

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stevelau1911
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Re: How much heat does a 400watt metal halide produce?

Post by stevelau1911 »

I haven't had problems with bugs in the past, but I've also never kept the greenhouse up through the warm months either. If I do, it is pretty easy to uninstall. I also don't see a need for ventilation when opening the door seems to keep the temperature from getting much over 100F. I was actually impressed by how quickly you were able to get fully leafed out culms so my guess is that the greenhouse had to do something with it. It seems like bamboos need warmer temperatures in order to continue their growth.
http://bamboonetwork.org/downloads/chinesemoso.pdf

Hardiness
Moso bamboo is located in hardness zones 7, 8, 9 and 10.
Zones 7, 8, 9 and 10 have mean annual minimum temperature
-17.7 to -12.3°C (0.14 to 9.8°F), -12.2 to -16.7°C (10 to -1.9°F),
-6.6 to -1.2°C (20 to 29.8°F) and -1.1 to 4.4°C (30 to 39.9°F)
respectively, but the central distribution zone is in zone 9 and
8. Moso bamboo grows naturally in subtropical monsoon
climate zone (in summer high temperatures and rainy; in
winter cold and dry). The mean annual temperature varies
from 15 to 21°C (59 to 69.8°F), with a mean temperature of
the coldest month being 1 to 12°C (33.8 to 53.6°F), the mean
annual minimum temperature ranging from -1.2 to -18°C
(29.8 to -0.39°F), and that of the warmest month from 26 to
29°C (78.8 to 84.2°F). Moso bamboo can withstand -18 to
-20°C (-0.39 to -4°F) in the winter. The annual precipitation is
between 800 to 1800 mm (31½ to 71 inches). The restricting
factors for Moso distribution are the annual precipitation (800
mm or 31½ inches) and minimum temperature in winter in
the north, and drought in spring in the south. Spring drought
makes shooting difficult.
According to this pdf, the conditions that are created by installing a greenhouse will bring the climate very close to the ideal temperatures, especially in the winter. I think letting the greenhouse get below freezing may be a waste of valuable growing time when they would be better off in the 1 to 12C for vernalization. The only drawback to having a greenhouse is that it also blocks out all the rain water so it becomes necessary to water all the plants inside around once a week.



I also found a pretty good video on solar greenhouses. This guy is claiming 21F of temperature differential with his setup going from 19F to 41F which is around 5F better insulation than what I've gotten in the past through the night. Some of his tricks were covering up the entire glazed area over the night, frost protecting the plants inside, and additional layering where heat tends to escape which is not that hard to replicate.




As far as taking care of the CO2 problem, I already have a rotting log in there, but one thing I plan on doing is sticking a large bag with saw dust & manure, then throw in some of my shiitake, and reishi mushrooms as well as some of the wild species to make sure that there's a CO2 generating mass of materials in there. Keeping 1 zipper open should be enough to help the air circulation.
stevelau1911
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Re: How much heat does a 400watt metal halide produce?

Post by stevelau1911 »

http://www.amazon.com/dp/B001C89GV8/ref ... T1_3p_dp_1

I just installed the solar vent/fan on the south side of the greenhouse where it is around 45 degrees in order to be the most effective. It seems to turn on instantly even when it is cloudy. When the sun comes out, the fan spins a bit faster so I no longer have leave the door wide open for air ventilation. The purpose of this fan is to blow all the oxygen and humidity out of the greenhouse so that fresh air can circulate into the greenhouse from all the little gaps at the bottom of the greenhouse. It should also only turn on when it is needed since the only time there should be a CO2 deficiency is when the sun is shining which also turns on the solar fan.

Even though the entire cover has been tied down to the ground very tightly, there' still the threat of it getting ripped or blown off, and leaving the door open which is on the west side basically turns the entire greenhouse into a sail.
johnw
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Re: How much heat does a 400watt metal halide produce?

Post by johnw »

Steve - It's imperative that you get those gaps at the base filled in or cover the bottom edge of the plastic with a goodly amount of soil. A friend bought a big 30 x 100ft hoop house and her husband while he had anchored the arch bases to the 6x6 base framing he somehow forgot to anchor the 6x6's down with bent rebars driven into the ground. The whole thing took off in a windstorm breaking the roof joists of their barn and trashing their pickup truck. When the greenhouse company trouble-shooter came to look at the whole affair the entire hoophouse was crumpled into an incredibly small heap, no coverage.

There are also braces that you should make sure you have that keep the structure from moving from end to end. They go from each corner of the front end to the first arch and same for the rear end. If you go to a ghouse website (http://ggs-greenhouse.com/coldframes) you should see them in plans, forget what they're called but I know customers sometimes install them backwards and get into big trouble through the winter.

johnw
Last edited by johnw on Sun Sep 23, 2012 3:03 pm, edited 1 time in total.
johnw coastal Nova Scotia
stevelau1911
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Re: How much heat does a 400watt metal halide produce?

Post by stevelau1911 »

I am looking to get those thin tent stakes off of eBay since the cover does have tie down points which should secure it down once all of them are in, and I use cinder blocks to add a bit of insurance. I am well aware that I can't afford to have the whole thing blow off during a blizzard, especially if the plants are used to being several degrees warmer than the outside temperature. The only reason I'm leaving the gaps on the corners open now is because the temperatures are still relatively warm. I have also added a 3rd 55 gallon drum filled with water to make sure the greenhouse doesn't freeze over as easily. When December comes, it will be much better insulated than it is at the moment.

I also plan on having a tarp tied down over the entire setup which will allow wind to blow over the greenhouse as opposed to directly into it. This should serve as another layer of insulation, and also protect half of the plastic on the greenhouse.
stevelau1911
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Re: How much heat does a 400watt metal halide produce?

Post by stevelau1911 »

I'm not sure if adding my 3rd 55 gallon water barrel was the cause, but instead of a 6-7F difference in night time temperature, the differential is 9.3F tonight, rising from 45F to 54.3F. The full sun today might also be a part of it. It is still possible for me to fit around 6 more barrels of water in there, maybe even more if I stack them, but this greenhouse seems to be working better than my old one. I'm hoping on a night where it reaches 0F, the temperatures inside of the greenhouse can be above 25F without any intervention. I just want to see if I can insulate one of these greenhouses to the point that they can over-winter temperate plants with ease.

Here's the greenhouse.
http://stevespeonygarden.blogspot.com/2 ... house.html

Image
stevelau1911
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Re: How much heat does a 400watt metal halide produce?

Post by stevelau1911 »

I now have 4 55 gallon barrels filled with water for my thermal mass inside the greenhouse, and added a double layered insulation tarp to shield the north, and west side. I want to make sure that the cold air blowing on a winter night can't radiate into the greenhouse that easily. I figured that on cold windy nights, the greenhouse tended to cool down a lot faster. Another purpose this serves is preventing drafts of snow from making it impossible to get inside the greenhouse.

Here's the new look.
Image

Image

More leaf bags will be needed to line up the entire north side.
Image
stevelau1911
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Re: How much heat does a 400watt metal halide produce?

Post by stevelau1911 »

After adding a compost pile in the middle of the greenhouse, it looks like the trend has been hotter days while the night times do not change much. It seems like warmer temperatures can trigger the compost pile to heat up and generate even more heat. For instance, it was at one point only 57F outside while the greenhouse temperature was 98F. I was hoping that it would create more of a warming effect at night, but that shouldn't be a big issue at this point because it probably won't get anywhere near freezing in the next month inside the greenhouse.

As shown in this picture, this compost pile is nowhere close to its full potential in heat production so I am expecting it to rise into the 100s once we warm back up in the following week.
Image


I hope this pile can still heat up in the middle of winter when it is needed the most. For the time being, I'm trying to give the greenhouse some supplemental heat so that I can help my new dahlia cuttings root out with the remaining warmth of 2012.
Image

Image
stevelau1911
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Re: How much heat does a 400watt metal halide produce?

Post by stevelau1911 »

I ended up stuffing around 2 cubic yards total of greens and browns for my greenhouse compost pile so it is nearly stuffed to the roof. There's really no point for me to enter the greenhouse anyways so I don't mind sealing off the entire entrance as the pile has started to slowly generate heat. There should be enough time for it to break down all the way through the winter. I'm hoping this serves as an insulator on the west side of the greenhouse, a source of passive heat, and carbon dioxide. It has still ranged in the mid 50s to around 80F on average in the greenhouse, getting nowhere close to freezing so I still haven't used the metal halide or any other heating device. Once the compost pile breaks down a bit, I could probably shove more in there :mrgreen:

Since I only have 1 bottle left of my original lamp oil purchased a few years ago, I decided to go to Lowes to get a couple gallons of "Klean Heat" for around $10 each. It takes approximately $0.70 of lamp oil to defrost my greenhouse over 1 night at this price so it is pretty efficient. I just hope this brand of oil produces at least as much heat as my original type. I plan to keep the lamp in the greenhouse in case the metal halide bulb fails.

Image


I could make it a lot easier by simply sticking in a small space heater, but I enjoy playing around with alternative methods. This is probably the cheapest electric space heater I can get which has a fan, and only uses 100 watts of electricity.
http://www.ebay.com/itm/Mini-Portable-P ... 4ab899269b
stevelau1911
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Re: How much heat does a 400watt metal halide produce?

Post by stevelau1911 »

Just found something interesting where this guy is trying to sell this 1K-2K light, and badmouthing the metal halides/HPS lights. 100,000 hours + low heat sounds attractive, but based on my entire investment of $60 for the metal halide+ slightly higher electricity costs, this guy sounds like he's just trying to sell an overly priced item that hasn't even been tested on the market yet, and many new technologies are prone to having problems on top of the super high price. :twisted:



I'm pretty satisfied with the seedling results with the 400w metal halide which got them strong enough to handle direct full sun in late April when the seedlings went directly outside under the full sun with no signs of stress.

In other words, I don't think there's any need to pay hundreds let alone thousands of dollars for an indoor lighting system. I also think the 90w UFO lights that can be bought all over eBay are noisy and still too weak unless you have the light under 1ft away from the plants.
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Re: How much heat does a 400watt metal halide produce?

Post by canadianplant »

Thats because you got an amazing deal on those ballasts. The bulbs alone are a hundred bucks a piece retail.
stevelau1911
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Re: How much heat does a 400watt metal halide produce?

Post by stevelau1911 »

http://www.virtualsunhydroponics.com/Ag ... G.asp?rt=2



I'm getting a T5 to try out this winter, primarily for small plants. They have 54 watt bulbs at 5000lumens per bulb so they are pretty efficient, but I know a weakness of these flourescent tubes is that they don't have as strong of a range as the metal halides, but that's not a problem since they don't get nearly as hot which is good for seedlings. the set up is also not as heavy or bulky.

I have them at 6 6400K bulbs, but I'm not too concerned about warm light because I intend to have this set up right by a window.
mshaffer
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Re: How much heat does a 400watt metal halide produce?

Post by mshaffer »

I have a 400w metal halide in my bedroom. It gets warm but you can touch it without burning yourself. I recently noticed when I was in the attic that it was warming up the insulation on the other side of the ceiling. :o But it has never caused a fire fortunately.
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Alan_L
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Re: How much heat does a 400watt metal halide produce?

Post by Alan_L »

mshaffer wrote:I have a 400w metal halide in my bedroom...
:shock: I don't see any plants under those -- overkill for room light, isn't it? :D
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Re: How much heat does a 400watt metal halide produce?

Post by mshaffer »

Yes I guess you are right. I actually just sold it since I couldn't use it anymore without one side of my face getting really fatigued.
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