High Tunnel Gets Colder Than Outside - Page 7

Cole_Robbie · November 20, 2017

Thanks for the tips.

My heater still shut off! I was confident that it would be fine with a fresh air intake, but I don't think it ran any longer than it did with the doors closed. It was 23 last night, and everything is still ok, even my hot pepper plants.

AKmark · November 22, 2017

Quote:

Originally Posted by 4season

I think pyrethrin or the synthetic analog permethrin will kill aphids. If I remember correctly some military clothes for jungle use are lightly infused with pyrethrin, low toxicity to mammals but bad for aquatic life.

It is only decent, it never kills all aphids, it is so irritating I stopped trying it. I use beneficial s solely now, they are expensive much much cheaper than a crop loss. I do this commercially, and this is what I have learned.

AKmark · November 22, 2017

Quote:

Originally Posted by Cole_Robbie

Thanks for the tips.

My heater still shut off! I was confident that it would be fine with a fresh air intake, but I don't think it ran any longer than it did with the doors closed. It was 23 last night, and everything is still ok, even my hot pepper plants.

Try a wood furnace, the outside is not hot, and you can run duct the entire length of your GH to spread the heat evenly by drilling a small hole every two feet in the top of the duct, you also must partly seal the end. I use these as back up in some GH's in case a natural gas heater fails in the early spring when we start our production.

Cole_Robbie · November 24, 2017

I have a wood furnace. That was my original idea. But even with a blazing fire and an inflated double layer of poly, I could only get 15 degree above the outside temperature. My furnace is very big, and in an adjacent building. I might have done better with a small stove located inside the greenhouse itself.

I think you hit the nail on the head with the beneficials, though. I have aphids and whiteflies so badly that they are never going away. Controlling them is more realistic than getting rid of them.

AKmark · November 27, 2017

I have mine in the GH's. I get about 12 degrees in my biggest one,
about 20 in a 72 x 30, and 30 plus in a 50 x 30. Even 12 degrees is a plus,
that saves a bunch of natural gas for me. I only have them in production GH's that I fire up early, I heat water with them, and they are back up in case a heater goes down.

Quote:

Originally Posted by Cole_Robbie

I have a wood furnace. That was my original idea. But even with a blazing fire and an inflated double layer of poly, I could only get 15 degree above the outside temperature. My furnace is very big, and in an adjacent building. I might have done better with a small stove located inside the greenhouse itself.

I think you hit the nail on the head with the beneficials, though. I have aphids and whiteflies so badly that they are never going away. Controlling them is more realistic than getting rid of them.

Black Krim · January 26, 2018

While I want a GH set up asap to use this spring, the cooling on a cold clear night will negate all the weeks of growing before the frost. And make a GH useless, for me. In seeking a solution .....

A few thoughts......

Keep small farm animals inside the HG; like rabbits, chickens, turkeys, goats. Mini horse. They provide a source of heat. I have no experience with a green house, so if high humidity then not a good environment for animals as their lungs are negatively affected by humidity. Perhaps only on the high risk nights. DH and I would bring the 4 dogs into our bedroom on a "four dog night"--the extra body weight of 4 big dogs made a noticeable difference.

A chicken coop design that is very successful in colder climes called the Woods Style is counter intuitive as it has one open side facing south. Storms roll in from the west or the NE, not the S, generally speaking for the northern US. The basic idea is a test tube laid on its side. It actually has a door and a vent, so the first half of the structure has air flow ( thru open end up to roof vent)but when the vents are tightly closed, air flow decreases and the air in the back is still. And warmer. This is designed for chickens. Like plants they give off a lot of humidity, but they produce far more heat than plants. Chickens can handle extreme cold if they are protected from drafts and their air is dry. This is my favorite coop design.

Here is a very good pictorial showing the design. My coops are longer.
https://www.backyardchickens.com/thr...e-coop.672804/

This may be in line with the idea of opening the door for a tunnel. The air exchange is slow and steady.

As for increasing humidity, NOT using humidity protected the tomatoes better, per a TV post. I think MrBig45 wrote about it in his growing cold tolerant varieties in the Czech Republic.

Another idea whirling in my head is a buried fire pit, like a pig roast type. Burns slow. Unsure of the full impact of the gases on the plants though. Or a wood stove, piping the gasses outside the structure but run as much piping thru the length of the structure as that pipe gets HOT. Running it along the ground makes the most sense as cold air settles and warm air rises.

Would like to hear what you think.

Black Krim · January 26, 2018

https://www.youtube.com/watch?v=VqZn...3gp6ZsoM-BvdmM

The user of his small green house logged temperatures, hi, low, and inside GH. Im wondering why his small GH performed differently?

Cole_Robbie · January 27, 2018

He only tracked it for two weeks, which is probably not a large enough sample size. I don't have anything growing in the dead of winter, either. I don't know if that affects the phenomenon. Also, I think it would only be relevant when growing just under a single layer of plastic, so if you did have low tunnels or hot boxes like he had, then it would not be a concern.

Humidity is great when it's cold, but not good when it is hot outside.

I think the best design for heating would be to heat water, and then circulate that water through the floor. Obviously that is a bit of an investment.

The best off-grid design I have seen is "active solar." A few panels run fans that blow hot air through pipes in a gravel floor during the day. At night, the fans reverse, and pull air up out of the warm gravel. That design outperforms "passive" solar, which is a typical unheated greenhouse with any mass in it. I have a thick gravel floor, which I think helps a lot to store heat, but I would do better with the active solar setup; I just didn't have the money to build it.

BlackBear · January 27, 2018

Quote:

Originally Posted by Cole_Robbie

He only tracked it for two weeks, which is probably not a large enough sample size. I don't have anything growing in the dead of winter, either. I don't know if that affects the phenomenon. Also, I think it would only be relevant when growing just under a single layer of plastic, so if you did have low tunnels or hot boxes like he had, then it would not be a concern.

Humidity is great when it's cold, but not good when it is hot outside.

I think the best design for heating would be to heat water, and then circulate that water through the floor. Obviously that is a bit of an investment.

The best off-grid design I have seen is "active solar." A few panels run fans that blow hot air through pipes in a gravel floor during the day. At night, the fans reverse, and pull air up out of the warm gravel. That design outperforms "passive" solar, which is a typical unheated greenhouse with any mass in it. I have a thick gravel floor, which I think helps a lot to store heat, but I would do better with the active solar setup; I just didn't have the money to build it.

.
When do you consider the "dead of winter " nothing growing.......season (weeks) ?

Black Krim · January 27, 2018

Cole,Maybe someday you will realize that exact set up.... Until then Finding an economical second best may be good enough.

Cole_Robbie · January 29, 2018

Quote:

Originally Posted by BlackBear

.
When do you consider the "dead of winter " nothing growing.......season (weeks) ?

My coldest weather is usually from about Christmas through the end of January. It's a good time to give up gardening and let the cold weather kill the bugs and disease I have cultivated all summer.

I am just about to start my first seeds of the year inside, which should be moved out into the greenhouse about mid-Feb. When I only have a few flats of small plants, I can stack them on shelves, cover them with plastic, and put a heater underneath. They are fine that way, even with night temps into the low 20's. My problems arise when weather that cold arrives later in the spring, when I have a greenhouse full of larger plants.

Cole_Robbie · January 29, 2018

Quote:

Originally Posted by Black Krim

Cole,Maybe someday you will realize that exact set up.... Until then Finding an economical second best may be good enough.

The article that I read said it worked with a gravel floor. It would be fun to experiment a little further. I wonder if it would work better with concrete, or different sizes/types of gravel.

BlackBear · January 29, 2018

Quote:

Originally Posted by Cole_Robbie

My coldest weather is usually from about Christmas through the end of January. It's a good time to give up gardening and let the cold weather kill the bugs and disease I have cultivated all summer.

I am just about to start my first seeds of the year inside, which should be moved out into the greenhouse about mid-Feb. When I only have a few flats of small plants, I can stack them on shelves, cover them with plastic, and put a heater underneath. They are fine that way, even with night temps into the low 20's. My problems arise when weather that cold arrives later in the spring, when I have a greenhouse full of larger plants.

I am not sure all your environmental circumstances ....but maybe it seems a bit counter intuitive ...just to move your seedlings start time and back time about 10 days

save some heat time/budget .....less of a risk for cold ....and greater photo period in the day etc.....also if you start them to soon ...there may not be a safe place for them to go when they get bigger etc.

In my circumstance it made sense to move my seedling start times back ..for
heat/ space / photoperiod / in order to be more efficient for my open tunnel .

I always used to chomp at the bit to start seedlings week of Ground hog day (Feb.2 +) But I always now actually activate seedling start about Feb.15(or later) and
have open tunnel and it works out much better for .....protection/ heat / space /.
It didn't solve all the risks and problems ...but sure made it better.

In your case a later start may save you some heating /cost and lessen /avoid that "late spring" freeze problem . ????

Cole_Robbie · January 29, 2018

This upcoming spring will be my 7th year selling plants at market. I find that the more years go by, the later I start everything. My cousin just built his first high tunnel and is new to growing. He started his seeds two weeks ago.

Sunshine to heat up the greenhouse during the day is an important factor, and I often don't get good sun until late Feb or early March. My 'dead of winter' weather is often cloudy.

BlackBear · January 29, 2018

Quote:

Originally Posted by Cole_Robbie

This upcoming spring will be my 7th year selling plants at market. I find that the more years go by, the later I start everything. My cousin just built his first high tunnel and is new to growing. He started his seeds two weeks ago.

Sunshine to heat up the greenhouse during the day is an important factor, and I often don't get good sun until late Feb or early March. My 'dead of winter' weather is often cloudy.

I am NOT commercial ...Just a crazy hobbyist ....but

It is so tempting to get going and start ...and green up early.

BUT ...it costs money for the heat you could have a partitioned part of green house (only heat a part ) and move and expand as the season is safer . and 10 days is 10 days for start up. The early start with not the safe cover or heat ...risks your whole venture for the season . Extra heat costs is also part of your bottom line ...to be balanced with the earlier start ...etc. for me the later start is the cost effective balance . I guess everybody must do their own circumstance assessment. It sure is a little dance to get the earliest start versus . protect against the cold etc.

I guess if we all lived in Florida this would not be such a worry .

January 26, 2018	#96
Black Krim Tomatovillian™ Join Date: Dec 2016 Location: New England Posts: 661	While I want a GH set up asap to use this spring, the cooling on a cold clear night will negate all the weeks of growing before the frost. And make a GH useless, for me. In seeking a solution ..... A few thoughts...... Keep small farm animals inside the HG; like rabbits, chickens, turkeys, goats. Mini horse. They provide a source of heat. I have no experience with a green house, so if high humidity then not a good environment for animals as their lungs are negatively affected by humidity. Perhaps only on the high risk nights. DH and I would bring the 4 dogs into our bedroom on a "four dog night"--the extra body weight of 4 big dogs made a noticeable difference. A chicken coop design that is very successful in colder climes called the Woods Style is counter intuitive as it has one open side facing south. Storms roll in from the west or the NE, not the S, generally speaking for the northern US. The basic idea is a test tube laid on its side. It actually has a door and a vent, so the first half of the structure has air flow ( thru open end up to roof vent)but when the vents are tightly closed, air flow decreases and the air in the back is still. And warmer. This is designed for chickens. Like plants they give off a lot of humidity, but they produce far more heat than plants. Chickens can handle extreme cold if they are protected from drafts and their air is dry. This is my favorite coop design. Here is a very good pictorial showing the design. My coops are longer. https://www.backyardchickens.com/thr...e-coop.672804/ This may be in line with the idea of opening the door for a tunnel. The air exchange is slow and steady. As for increasing humidity, NOT using humidity protected the tomatoes better, per a TV post. I think MrBig45 wrote about it in his growing cold tolerant varieties in the Czech Republic. Another idea whirling in my head is a buried fire pit, like a pig roast type. Burns slow. Unsure of the full impact of the gases on the plants though. Or a wood stove, piping the gasses outside the structure but run as much piping thru the length of the structure as that pipe gets HOT. Running it along the ground makes the most sense as cold air settles and warm air rises. Would like to hear what you think. Last edited by Black Krim; January 26, 2018 at 03:46 PM.

November 20, 2017	#91
Cole_Robbie Tomatovillian™ Join Date: Jun 2012 Location: Illinois, zone 6 Posts: 8,407	Thanks for the tips. My heater still shut off! I was confident that it would be fine with a fresh air intake, but I don't think it ran any longer than it did with the doors closed. It was 23 last night, and everything is still ok, even my hot pepper plants.

November 24, 2017	#94
Cole_Robbie Tomatovillian™ Join Date: Jun 2012 Location: Illinois, zone 6 Posts: 8,407	I have a wood furnace. That was my original idea. But even with a blazing fire and an inflated double layer of poly, I could only get 15 degree above the outside temperature. My furnace is very big, and in an adjacent building. I might have done better with a small stove located inside the greenhouse itself. I think you hit the nail on the head with the beneficials, though. I have aphids and whiteflies so badly that they are never going away. Controlling them is more realistic than getting rid of them.

January 27, 2018	#98
Cole_Robbie Tomatovillian™ Join Date: Jun 2012 Location: Illinois, zone 6 Posts: 8,407	He only tracked it for two weeks, which is probably not a large enough sample size. I don't have anything growing in the dead of winter, either. I don't know if that affects the phenomenon. Also, I think it would only be relevant when growing just under a single layer of plastic, so if you did have low tunnels or hot boxes like he had, then it would not be a concern. Humidity is great when it's cold, but not good when it is hot outside. I think the best design for heating would be to heat water, and then circulate that water through the floor. Obviously that is a bit of an investment. The best off-grid design I have seen is "active solar." A few panels run fans that blow hot air through pipes in a gravel floor during the day. At night, the fans reverse, and pull air up out of the warm gravel. That design outperforms "passive" solar, which is a typical unheated greenhouse with any mass in it. I have a thick gravel floor, which I think helps a lot to store heat, but I would do better with the active solar setup; I just didn't have the money to build it.

January 27, 2018	#100
Black Krim Tomatovillian™ Join Date: Dec 2016 Location: New England Posts: 661	Cole,Maybe someday you will realize that exact set up.... Until then Finding an economical second best may be good enough.

January 29, 2018	#104
Cole_Robbie Tomatovillian™ Join Date: Jun 2012 Location: Illinois, zone 6 Posts: 8,407	This upcoming spring will be my 7th year selling plants at market. I find that the more years go by, the later I start everything. My cousin just built his first high tunnel and is new to growing. He started his seeds two weeks ago. Sunshine to heat up the greenhouse during the day is an important factor, and I often don't get good sun until late Feb or early March. My 'dead of winter' weather is often cloudy.