Green house questions

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Tora
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Post by Tora »

Update on the banana greenhouse

Finally got the blower hooked up and hopefully working full time to keep the greenhouse looking like the Stay Puff Marshmallow Man. It’s supposed to be quite cold with potential snow tonight so I’d say it got done just in time.

I the blower I got was a bit too strong and was deforming the split bamboo ribs on the lower walls of the greenhouse where the walls are quite straight. I reinforced the walls with a couple horizontal (perpendicular to the ribs) runs of whole/round bamboo on each side and a couple extra reinforcements I learned from being a builder. I also ran the power through a light dimmer switch to slow the motor down when the plastic puffs up. It’s a very low power motor so most of the other speed controller devices seemed to be over kill or just didn’t work. It took a lot of research to figure this out.

Also, I filled up the compost bin (a couple times!) I made inside the greenhouse and it feels like it’s heating up now. I think adding kitchen scraps and a little chicken manure to the pile was a mistake as it was a little stinky for a while and there are flies in there now. Seems better a couple weeks later but maybe I just got used to it. I’m not in there much so I guess it’s not a problem if it’s a little stinky.

I’ve also been burning a little homemade charcoal in an old hibachi on colder nights when the temperature dips below 6-7 degrees. Some leaves had been turning yellow before I started this and that is a sign that the plant is too cold. Not sure about the effects of carbon monoxide on the plants. I’ve read up on it a bit and it seems it can be positive or negative based on the plant and the stage. I do try open up the door and window to let fresh air in once or twice a day and definitely if I’m gonna be working inside the greenhouse after burning charcoal.

This all seems to be working as I see growth again after all growth had stopped for a month. It’s very slow but at least this indicates to me that I’ve created a warm enough space for the plants to survive and maybe even keep growing over the winter. I’m hoping that the added air space between the two layers of plastic will keep things even warmer inside.

Finally, if anyone has had the patience or attention span to get this far, the plastic on the upper walls-roof of the greenhouse seems to be stretched too tight to allow much if any air between the 2 layers. If anybody has any suggestions other than loosening up the plastic or tie down straps (the strong winds we’re having tonight suggest that might be a bad thing), I’d be interested to hear them. I did use some flexible aluminum duct to to bridge areas that had air flow with areas that seemed to have little or no airflow. This was in one of the videos (Gonbechan?) posted above. I might try to put in another bridge or two to help more air get to under-inflated areas when things dry out.

And thanks Gonbechan. You’re on the list of banana recipients should I get a tasty harvest!

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Zasso Nouka
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Post by Zasso Nouka »

Do you think carbon monoxide is a real danger in there ? Detectors are quite cheap on Amazon if you think it's a real risk, alternatively it could be a plus in that it might kill any insects with hostile intentions towards your bananas :lol:

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Post by gonbechan »

Tora wrote:
Fri Dec 17, 2021 6:02 pm

And thanks Gonbechan. You’re on the list of banana recipients should I get a tasty harvest!
ooo. I wish your banana plant a fecund existence.

Señor Gonbe went to a new supermarket in our area last weekend. They had huge bunches of bananas for 200yen.
We tried really hard to eat them all, but today is going to be banana muffin (and mini banana breads) baking day.

Thank god we bought a bigger freezer haha.

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Post by Chuck2 »

Tora wrote:
Fri Dec 17, 2021 6:02 pm
Update on the banana greenhouse

Finally, if anyone has had the patience or attention span to get this far, the plastic on the upper walls-roof of the greenhouse seems to be stretched too tight to allow much if any air between the 2 layers. If anybody has any suggestions other than loosening up the plastic or tie down straps (the strong winds we’re having tonight suggest that might be a bad thing), I’d be interested to hear them.
Got any pictures of this?

Did you get much snow? Here we got a couple of inches.

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Post by Tora »

Zasso Nouka wrote:
Sat Dec 18, 2021 7:19 am
Do you think carbon monoxide is a real danger in there ? Detectors are quite cheap on Amazon if you think it's a real risk, alternatively it could be a plus in that it might kill any insects with hostile intentions towards your bananas :lol:
More worried about any effects on the plants. They spend more time breathing that air than me and I grew up with 2 parents who smoked when leaded gasoline was still a thing. I’m sure the damage has most likely been done :lol:

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Post by Tora »

gonbechan wrote:
Sat Dec 18, 2021 7:55 am
Tora wrote:
Fri Dec 17, 2021 6:02 pm

And thanks Gonbechan. You’re on the list of banana recipients should I get a tasty harvest!
ooo. I wish your banana plant a fecund existence.

Señor Gonbe went to a new supermarket in our area last weekend. They had huge bunches of bananas for 200yen.
We tried really hard to eat them all, but today is going to be banana muffin (and mini banana breads) baking day.

Thank god we bought a bigger freezer haha.
Mmmm banana bread! I need to get back into the kitchen. Feeling the need to fatten myself up for the cold season!

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Post by Tora »

Chuck2 wrote:
Sat Dec 18, 2021 10:14 am
Tora wrote:
Fri Dec 17, 2021 6:02 pm
Update on the banana greenhouse
…the plastic on the upper walls-roof of the greenhouse seems to be stretched too tight to allow much if any air between the 2 layers. If anybody has any suggestions other than loosening up the plastic or tie down straps (the strong winds we’re having tonight suggest that might be a bad thing), I’d be interested to hear them.
Got any pictures of this?

Did you get much snow? Here we got a couple of inches.
Chuck,

Just some small dust particle sized snow flurries here last night but the typhoon force NW winds last night were quite worrying at times. One of my neighbors might have lost one or more of his strawberry greenhouses last night had he not been out there late at night to make repairs and reinforcements. He lost a power line so he was adjusting temperature with manual ventilation and trying to find an electrician to come quick.

I tried to take some pics of the inflated and under-inflated areas between the plastic layers on my greenhouse this morning but really could not seem to capture an easy to understand image of what I was trying to explain. It’s pretty obvious to the naked eye but I haven’t found a way to capture it with a camera.

I’ll attach a pic of one side wall-roof-ceiling? area and try to explain it.

You can see the tops of two 6’ (182cm) ladders in the bottom center of the pic and the ridge pole at the top of the pic. The upper section is more curved and the lower half is more vertical so more stretch/pull on the plastic in the upper part and less in the lower section. There is black plastic tie down tape running between every rib and tied off at ground lever on both sides. The tie down tape really kept that huge greenhouse from sailing over the mountain in the typhoon force winds we had last night!!!

There is still a little air space (0-5cm) between the plastic layers in the upper section but it’s nowhere near the amount of air space in the lower and end sections(10-15cm?).

In my (overwhelmed) mind, more air space equals more insulation and, as heat rises, more heat will be lost through the upper areas of the green house. So, an under-inflated thus under-insulated ceiling area is losing a lot more heat than I think it should. How scientific is that?!

I bridged together a couple walls with aluminum duct like the kind bringing outside air into the blower in another of the pics. I could add other bridges to some of the upper sections but there seems to nothing stopping air from flowing up there from other areas besides the fact that the plastic seems too tight for the current air pressure.

The blower is currently running on low power- maybe 15%?. I could turn up the blower to increase air pressure (black switch in one of the pics) and possibly push more air up into the upper sections but it really seems to put a lot of stress on the ribs and plastic itself. However, I had problems with severe deformation of ribs when running the blower eat full power before reinforcing the ribs/sides and installing the dimmer switch on the motor.

Maybe I just need to make more time to experiment with settings or be happy that the air space I have now is better than the nothing I had before?

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Post by Chuck2 »

Tora,

Thanks for sharing the photos. Still admiring you built this all with bamboo!

I watched that YouTube video again and looking at your pictures. I agree with all what you said. Here are some new things I thought of:

1. Could you cut some holes in the interior plastic at the top of the greenhouse and add some kind of spacer, which would give you that 10-15cm space like the bottom side walls? And of course tape up these holes after adding these spacers.

2. Here is a little crazy idea and probably a lot of work. When I first heard about a greenhouse with 2 layers of plastic, I thought that you would have outside plastic layer on top of bamboo framing and inside layer on the inside of the bamboo framing. Inside framing would probably need a fare bit of c- channel so plastic doesn't fall down, but by doing this you would probably be able to keep a uniform space between the 2 plastic. But before doing this you would probably be better off just loosening the plastic and seeing if that fixes your problem.

3. Do you have more plastic? Lots of greenhouses in Japan that I have seen just hang an inner plastic ceiling. So like in your photo, you could just staple gun plastic to your shoulder bamboo frames. You could add a bridge of duct to this ceiling pocket or just leave it without blower air. Does that make sense? In the video the guy doesn't seem to care all that much how air tight everything is.

As for the YouTube video, it looks like his greenhouse doesn't really have much space between the two plastics near the top either but this is hard to confirm if that is true. So what you have know might just be fine. Are you checking what kind of temperature difference you are getting on cold nights?

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Post by Zasso Nouka »

@Tora I've edited your post to include the pictures. You need to post the link to the pictures themselves rather than the page they are displayed on. Ie the link should end in ".jpg" or something similar.

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Post by Tora »

Chuck2 wrote:
Sun Dec 19, 2021 11:31 am
Tora,

Thanks for sharing the photos. Still admiring you built this all with bamboo!

I watched that YouTube video again and looking at your pictures. I agree with all what you said. Here are some new things I thought of:

1. Could you cut some holes in the interior plastic at the top of the greenhouse and add some kind of spacer, which would give you that 10-15cm space like the bottom side walls? And of course tape up these holes after adding these spacers.

2. Here is a little crazy idea and probably a lot of work. When I first heard about a greenhouse with 2 layers of plastic, I thought that you would have outside plastic layer on top of bamboo framing and inside layer on the inside of the bamboo framing. Inside framing would probably need a fare bit of c- channel so plastic doesn't fall down, but by doing this you would probably be able to keep a uniform space between the 2 plastic. But before doing this you would probably be better off just loosening the plastic and seeing if that fixes your problem.

3. Do you have more plastic? Lots of greenhouses in Japan that I have seen just hang an inner plastic ceiling. So like in your photo, you could just staple gun plastic to your shoulder bamboo frames. You could add a bridge of duct to this ceiling pocket or just leave it without blower air. Does that make sense? In the video the guy doesn't seem to care all that much how air tight everything is.

As for the YouTube video, it looks like his greenhouse doesn't really have much space between the two plastics near the top either but this is hard to confirm if that is true. So what you have know might just be fine. Are you checking what kind of temperature difference you are getting on cold nights?
Chuck, thanks for your thoughtful reply. They are good ideas.

1. I had planned to do something like your first suggestion but got the first layer of plastic on and couldn’t figure you to affix the spacer piece on top of the ridge pole that was 5 meters up in the air. The. I remembered Gonbechan’s suggestion….

2. Adding another layer to the inside might not be too hard and might be the best solution. I could do it by screwing thin strips of wood to the bamboo to hold the plastic from the inside.

3. it seems something like idea #2 but I’m guessing with another internal frame like all the other greenhouses with 2 layers of plastic here. Also doable. I think I hesitated but o do this as I thought the bamboo would get saturated from all the condensation. It seems to get pretty wet with condensation having it between layers of plastic might not be much worse. That being said, I think I notice less condensation after staring to run the fan full time.

Regarding temperature, I have not been recording temperature. I want to monitor that but I just haven’t gotten another thermometer. I checked with our old school real mercury living room thermometer and it was about 6 outside, 9 in the greenhouse at head level and 24 in my living room. In general, it does feel a little warmer in the evening, a little cooler(?) in the early morning before the sun starts shining on that area and a lot warmer when the sun is shining.