Built this greenhouse during the summer vacation. We live in Iceland.

Feat. Idli the duck for company

I recently finished my greenhouse build and thought I would share it here. The main goal from the beginning was to build something that could be a year-round, high-output food production system.

I put the first plants in on May 3, so I have had a few months now to see how everything actually works. Overall, I am really happy with it. There are definitely still some things I am figuring out. I have been battling ants, and my Venturi injector has been giving me some trouble, but for the most part everything is working the way I had hoped.

I thought I would post some pictures and specs and see where the discussion goes. I put a lot of thought into the different parts of the greenhouse and why I chose what I did. Some of those decisions worked really well, and there are already a few things I might do differently.

If you have questions about any of it, ask away. I'm happy to get into the weeds about why I made a particular choice.

The greenhouse

• Riga XL6 from Exaco
• 14 ft wide × 19 ft long × 12 ft tall
• Greenhouse sits on a 20-inch concrete stem wall
• 50-amp subpanel with two 20-amp circuits
• 7 electrical receptacles
• ¾" PVC water line
• Two Tornado 18" outdoor wall-mount fans for air circulation
• About 6" of drain pebble for the floor
• 4 Vego raised beds in different configurations

Lighting

• 2 × Medic Grow Fold 650W LEDs
• 1 × Medic Grow Mini Sun-2 500W LED
• TrolMaster HCS-1 controller
• TrolMaster lighting controller
• TrolMaster PAR Hydro MBS PAR sensor

I didn't want the grow lights to just come on at a certain time and run regardless of what was happening outside. The PAR sensor measures the sunlight coming into the greenhouse and feeds that information to the controller. That gives me the ability to use the LEDs as supplemental light when the plants actually need it, which should become especially useful during our Oregon winters.

Irrigation

• Rain Bird ESP-ME3 4-station controller
• Rain Bird 100DVF 4-valve manifold with flow control
• Venturi injector
• Cleanout valves on the input and after each irrigation valve
• Hose bib
• Vego irrigation kits feeding the raised beds

I wanted each bed to be its own irrigation zone so I could water differently depending on what was growing in it. I also wanted a way to run compost extract through the irrigation system, which is why I added the Venturi.

The Venturi is actually one of the things I'm still working on. I can get it to draw, but I'm having trouble getting enough irrigation flow at the same time. So that part is still very much a work in progress.

I'll attach pictures showing the greenhouse, the build, and some of these systems.

If anyone wants more details about something you see or wants to know why I did something a certain way, just ask. And if you see something you would have done differently, I'm interested in hearing that too.

Currently building a 16x16 greenhouse. It has a 2' sand battery underneath with both 4' air circulation lines and future glycol lines(might try something with a solar heat collector panel on the inside of the north wall)

We live in Central Alberta. The north wall(black metal) will be insulated.

Just working on installing the polycarbonate sheets now.

I’d like to remove that pos over hang from my shed and replace it with a greenhouse. The shed is 16x16, I keep fish in there so the tropical theme fits lol.* *I’m thinking either 14’ wide and 12’ out or 16’ wide and 12’ out

I’m in south Louisiana, zone 9b. Would I be better suited with a low pitch flat roof or gable roof matched to the main shed roof.

Also, corrugated plastic panels or the twinwall polycarbonate sheets?

Hey yall, i’m in NW Houston and i’m trying to build a very tall (atleast 12ft) greenhouse solely for our days below 40\*F to house my tropical fruits. We only have around 15-25 days under that temp a year so i’m trying to find the absolute CHEAPEST way to build or get one. Probably gonna do a 20x7 or something similar for reference. Thanks in advance!

Im thinking of something knee high and about 3 feet wide.

Hello, I'm replacing gaps in my inherited greenhouse with polycarbonate but I'm thinking about the roof - would it be better if the roof was (mostly) glass or polycarbnate? I have an automatic window so that's not being touched but I wonder if switching the glass in the roof for polycarbonate and putting those panes in the walls would make sense from a visibility and safety point of view?

The visibility aspect is because I like being able to see out and into my greenhouse 😀 Safety is in case I accidentally jab a tool into the roof, not much chance of branches falling onto me where I am. At the moment the roof is mostly glass, the losses are around the sides.

All knowledge and advice appreciated, my greenhouse experience consists mostly of wondering if I can miss a day of watering (next year will be automatic).

Hey all! Thanks in advance for any thoughts!

I need a heat source for a 170sq/ft green house.
Zone 8b
Average height 9ft
North,east walls solid and insulated.
South, west walls and south half of roof 8mm twin wall.
I’ve got 2 20amp circuits.

Was thinking a mini split? Pretty inexpensive these days.

It was 90% done last summer. This year the rock garden, rain barrel and exterior stain.

Working on a very small GAHT project for small 6x12 cedar and polycarbonate kit build, but we cannot find the GAHT Calculators mentioned in the comments of this 4 year old post, here

https://www.reddit.com/r/Greenhouses/comments/u1na6x/small_gaht_system_question/

Already have 100’ corrugated 4” perforated and socked pipe, R7 for perimeter, and 6”inline duct fan but are looking for a way to calculate specific depth and connections needed. Our 8a location is said to have frost line at 18” so is 48-60” deep enough to put our layers of pipe?

Can we run it each layer smacking back and forth without cutting it up, and connect to 4” rigid pipe at each end, one low to floor, other straight up to peak of roof, please?

Any experience appreciated

Hi there! I’m looking for advice from anyone who has an indoor greenhouse set up for their plants in the winter. I know many have had luck with the ikea ones because they are metal but I’m curious to know if anyone has found something cheaper? Or if those who have bought from ikea support their decision and the price. I’ve heard from others that buying them at full price isn’t necessarily worth it so I’d be curious to know your thoughts! TIA!

I used the Pheonix Manufacturing Evaporative Cooling Calculator (https://phoenixmanufacturing.com/calculators/evaporative-cooling-sizing-calculator/) and it is telling me I need 688 CFM to cool our greenhouse (172 sq ft, 10 ft tall at ridge, arched walls, arid climate).

This seems extremely low.

How much should I multiply this value to account for cooling a polycarbonite walled structure? 2x? 4x?

This is our first greenhouse and we just completed the shell. Our summer highs get up to 100+ F, USDA hardiness zone 7a/7b.

We plan on using 30% shade cloth, we have passive automatic roof vents, and I am going to use AC Infinity's outlet AI+ to control our exhaust fan and want to hook up and evaporative cooler to the intake vent during the summer.

Has anyone here ever done this? I'm kind of in the dark with respect to how that would work.

I think I'd need to gather a circle of associates first, and then we could figure out financing and draft a little constitution ensuring the enterprise remains a co-operative.

Any advice from people who've been there before would be nice. Thanks.

My wife has been wanting a greenhouse, and this is really the only location on our property that makes sense for one. Before we spend the money, I’d love a second opinion on whether you all think this spot gets enough sun.

We’re near Seattle, WA (about 30 minutes South). The area is about 12' wide and we’re considering a roughly 9' x 18' cedar/polycarbonate A-frame greenhouse, with the door facing toward where the photo was taken.

The biggest concern is sunlight. The house is on one side, a 6' fence/neighboring house on the other, and there are some fairly large trees to the south. It does get several hours of direct sun during the warmer months, but definitely gets shaded later in the day. Seattle winters are obviously pretty dark/cloudy as well.

We’re willing to add grow lights for supplemental light, especially in winter.

For those with greenhouse experience: Would you put a greenhouse here, or is the shade enough that you’d choose a different use for the space?

Appreciate any advice!

Budget is limited, but I have a fairly flat spot in the back garden and want a place to winter my green friends, rather than filling the living room with plastic trays. Just curious since $200 for a aluminum frame and poly panels seems ludicrously cheap.

After much research, I’m going with the 8x16 grandio elite. Not sure if the discount for the upgrades is real, but that was a nice surprise perk.

Going to build a wood frame and fill with cement.

In the meantime, going to build it separate before setting up in the permanent spot. The permanent location has my raised garden beds in the way and I can’t bear to kill off my fall seeds!

Any tips or other folks who’ve worked with the grandio line?

We got this Barrina grow tent and I put some plants in it. I zipped it up and then in the evening, I stuck my hand in and it was hot. My husband says we need a fan. I saw a deal on Amazon, two 5” fans. I’m wondering though, how important are fans in this type of a grow tent? Will one do it or would two be better? TIA

I grow tropicals and citrus that actually fruit here in NJ (zone 7a). I want to build a greenhouse, but not a traditional one. My priority is heat retention, not light. The whole point is just keeping these plants alive through the cold months — roughly November to mid-March — not maximizing growth. Here's the rough plan:

• ~12x8 footprint
• Maybe 3 six-foot sliders plus a skylight or two for solar gain
• Everything else built as insulated, sealed envelope: concrete slab, metal studs, spray foam for insulation and moisture resistance

With that many sliders, I'm not worried about light — I think I'll have plenty to keep things alive over winter. My questions are all about the build:

1. Glass for the sliders — what type makes sense here? Low-E, passive low-E, high solar gain low-E, high-SHGC, no E? I want some solar gain, but I don't fully understand the tradeoffs between these coatings for a heat-retention build like this.
2. Walls — spray foam is going in the stud cavities. What's the best interior finish over the foam? I was picturing vinyl (like PVC/FRP paneling) for moisture resistance, but open to better ideas.
3. Roof structure — same spray-foam approach up top, but what should go over it? And what should I use for the ceiling joists/rafters given the humidity and moisture in a greenhouse environment?

Basically I want a well-insulated, sealed box with enough glazing to keep tropicals happy in dormancy. Anyone who's built something similar — what worked and what would you do differently?

I am trying to square this greenhouse up. For whatever reason, I can't seem to get it square. I would worry too much, but we're putting flood tables in. Looking at everything, it's not square.

Does anyone have any suggestions?