Large Scale Earth Sheltered Greenhouse

[live resin]

Can anyone offer tips on the design and construction of a 100' x 100' earth sheltered light dep greenhouse?

I'm thinking about building a dugout greenhouse because of the extreme long summer heat. From June to Oct the highs are 85-105F, low winter temps are around 20F. Also, to blackout the greenhouse I would only have to cover the top.

Is digging 8-10 ft below ground to take advantage of geothermal cooling viable on this scale?

I'm also leaning towards a high pressure fog system to complement sun shades in the summer. Any thoughts on these systems?

 

[Mikell]

 

[mojave green]

Water drainage below ground is challenging.

 

[Pangea]

I dont think it would be very effective in cooling the summer heat at all, Id guess it would be harder, most greenhouses will have their side walls open to help maintain temps in the extreme heat. Where is the cooling suppose to come from? The walls will literally do nothing in 105oF other than act as a huge barrier and insulator, the walls will absorb the heat from every warm day previous to the peak summer days and provide no effective cooling during the day when the suns heat is direct. If you make it an actual greenhouse and not a tarp hoop then you mean to have a film covering during summer as well? Youd make an oven that requires more extensive ventilation and cooling, not less.

Id say such style of environment is better suited to keeping in the warmth during winter.

 

[live resin]

Where is the cooling suppose to come from? The walls will literally do nothing in 105oF other than act as a huge barrier and insulator.

6+ under the ground is 50-60F year round, no matter the surface temperature.

The earth walls are perfect insulators, they are a giant heat sink that absorb solar energy that would otherwise heat the greenhouse. This is the whole premise of walipini style greenhouses.

I know geothermal cooling is effective at small scales, but not sure if that transfers well to a 100' x 100' space. Would I need to dig deeper for a larger area?

The point here is to be below ambient temps in the greenhouse from jun-oct. Opening side walls on an above ground greenhouse would at best give me ambient temps.

I have greenhouse fans capable of moving plenty of air. Is a fog system or swamp cooler easier to implement at this scale?

 

[Limeygreen]

If you have access to a well or water source (well is much cheaper) you run a pump of the cold water in tubes much like a heating pipe but with cold water, you can run this throughout the crop to help cool it down but how much I am not sure but it should work well in a 100 x 100, you just need an exit resivour to dump the water in if it warms up too much to be effective to cool, later it could be pumped back once cool again.

 

[tech1234]

After last years run I am currently thinking (at least small/med scale) a greenhouse is more effort than its worth. I think the ultimate set up would be:

-small greenhouse for early season temps (small so easy to heat)
-move out side to large pots with triple remesh cages
-have a half-ass pergola style uprights with crosses pre-setup to pull a cover over when late season rains are predicted.
- a lot of the big cali guys do this

this way you:
-can start early
-not have to remove heat and humidity
-have free wind (no fans needed)
-have full sun (even the best covers reduce light)
-nature helps with the bugs (birds, bats, lady bugs ect)

But I could be wrong... Also this doesn't help security

 

[live resin]

Tech, totally agree with your suggestions for an ultimate full sun grow (which I will do as well). However, my main focus now is 4-5 high quality light dep harvests per year, so I can have a continuous 50lb a week flow of material for concentrates, and flowers that can be passed of as indoor at dispensaries (only way to make decent $).

I have 40 remote off grid acres with endless well water to make this happen. I'm working this by myself so I'm open to any ideas to make an operation this size less labor intensive

 

[growingcrazy]

I am in the planning process of something similar for my farm. Looking forward to see where this goes.

 

[Pangea]

How much exactly is endless well water? What kind of flow rate is key, how big of diameter is your well. Do some googling on commercial greenhouse cooling systems, there are a few basic type systems, but to combat high heat most people(commercial greenhouse's) use a evaporative cooling method, theres all sorts of systems, farmtek has a few to get an idea of price and styles. It depends on how hardcore you want to go. The best greenhouse environmental system I know of would be the Agra Kool II.

The temp 6 feet down is just that, the temp 6 feet down, it takes all years temp to average that out, means it takes along time for temp to radiate one way or the other through it, especially talking about moving the cold depth to the warm surface. You have to soak up the cold and move it to the surface somehow, thats whats happening with your well water already.

 

[tech1234]

Tech, totally agree with your suggestions for an ultimate full sun grow (which I will do as well). However, my main focus now is 4-5 high quality light dep harvests per year, so I can have a continuous 50lb a week flow of material for concentrates, and flowers that can be passed of as indoor at dispensaries (only way to make decent $).

I have 40 remote off grid acres with endless well water to make this happen. I'm working this by myself so I'm open to any ideas to make an operation this size less labor intensive

my bad I didn't catch the light dep part.

man GHs are already and heat/airflow/humidity nightmare without pulling a solid black cover over it. I know people pull it off well which always amazes me

Ive been thinking about running a small pcv hoop house dep run this year as an experiment

 

[atk7]

build in phases?

build in phases?

this could be interesting, have been thinking of something similar, but much smaller scale for some different reasons (water conservation and cooling, as have spot in high desert area) so pulling up a chair. Maybe rather than one very large green house do three or four, each a third or quarter of the size . Do one of them to start with and add more after you learn the best practices and pitfalls from the first one . This may make black out covers easier to pull over also.

 

[Limeygreen]

Most growers use gutter or ridge vents as means to cool and airflow in north america, the fan and pad is popular in hotter and drier areas as it is more efficient there. If you get the correct number of plants in a greenhouse and they have good canopies and roots it helps cool down the greenhouse significantly.

 

[live resin]

Pangea, I'm told the well is good for at least 250,000 gal per year, I'l find out the flow rate this month when I hook up a genny to the well pump. I'm also on a creek so I may supplement the well if necessary. That positive pressure system is dope, but probably out of my price range initally. Which of those types of systems do you think uses the least electricity? Is a fog system just going to cause PM and mold?

Limey, the fan and pad is probably exactly what I need. There is already a swamp cooler on the roof the house for cooling, I should just get another one. Any experience with the automatic solar-powered greenhouse vents?


Anyone in Norcal have suggestions on best value for 10,000 sq ft each of greenhouse plastic, blackout fabric, and sun shade fabric?

 

[Mikell]

What kind of weeping tile system are you planning? Imagine there would be quite a bit.

Wall/floor system?

I love everything about this thread

 

[trichrider]

first thought.
100x100 would be more than difficult.
suggest (like prior poster) several smaller ones or one long rectangular, say 20x500.
open 1000ft area will not likely cool as efficiently, and smaller trenches will be easier to excavate and cover.
plus a fan at either end will keep air moving as opposed to trying to mix air in larger space.
i would dig a pilot hole to see where water table exists (or not)....see clay layers for drainage...

make it fun.

 

[MuricanWeedwolf]

Can anyone offer tips on the design and construction of a 100' x 100' earth sheltered light dep greenhouse?

I'm thinking about building a dugout greenhouse because of the extreme long summer heat. From June to Oct the highs are 85-105F, low winter temps are around 20F. Also, to blackout the greenhouse I would only have to cover the top.

Is digging 8-10 ft below ground to take advantage of geothermal cooling viable on this scale?

I'm also leaning towards a high pressure fog system to complement sun shades in the summer. Any thoughts on these systems?

I would just suggest using a greenhouse covering with a decent R value and get multiple evaporative cooling pad systems. It should keep your whole greenhouse at the right temp if you size it correctly.

 

[stoned-trout]

I saw one once with railroad ties for the walls it was only dug down like 5 ft tho.....dude did ok....yeehaw

 

[growingcrazy]

How much exactly is endless well water? What kind of flow rate is key, how big of diameter is your well. Do some googling on commercial greenhouse cooling systems, there are a few basic type systems, but to combat high heat most people(commercial greenhouse's) use a evaporative cooling method, theres all sorts of systems, farmtek has a few to get an idea of price and styles. It depends on how hardcore you want to go. The best greenhouse environmental system I know of would be the Agra Kool II.

The temp 6 feet down is just that, the temp 6 feet down, it takes all years temp to average that out, means it takes along time for temp to radiate one way or the other through it, especially talking about moving the cold depth to the warm surface. You have to soak up the cold and move it to the surface somehow, thats whats happening with your well water already.

I think the best method for cooling something like this is a closed loop underground earthtube system. Ventilation air from the house can pass through the tubes buried 6-10 feet underground. When the air returns to the house it should be in the low 60s.

This same system is used to heat the house in the winter. constant 55-60* air from the earthtubes circulating.

These type of houses work best in a system less than 30' wide with really an unlimited length depending on construction of the buried back wall.

China has been using above ground, red brick walled houses in cool weather with good results


Basically, build and Earthship greenhouse.


Keep on farmin!
GC

 

[megayields]

I dont think it would be very effective in cooling the summer heat at all, Id guess it would be harder, most greenhouses will have their side walls open to help maintain temps in the extreme heat. Where is the cooling suppose to come from? The walls will literally do nothing in 105oF other than act as a huge barrier and insulator, the walls will absorb the heat from every warm day previous to the peak summer days and provide no effective cooling during the day when the suns heat is direct. If you make it an actual greenhouse and not a tarp hoop then you mean to have a film covering during summer as well? Youd make an oven that requires more extensive ventilation and cooling, not less.

Id say such style of environment is better suited to keeping in the warmth during winter.

"extensive" ventilation I would think...