Greenhouse / shed design recommendations?

[Dogestoevsky]

Hi all, creating this post in the hopes that some of y’all might share your opinions and experiences with greenhouse / potting shed / unheated winter storage designs that you have or wish you had. We have the opportunity to plan some new construction for our (small) backyard, and lacking a garage we are hoping to create an out building that can serve as garden tool storage, winter tree storage for me, and a small greenhouse for starting veggies indoors and a few of my tropicals.

At the moment I’m just browsing the web for ideas, and I’ve been following along with other threads of individuals who are currently building their dream landscape (shoutout in particular to @markyscott, congrats on getting the new barn up).

What are your “must haves” in a greenhouse? In a winter storage space? Do you have a particular type of construction you recommend? Would you consider prefab?

Here are a couple images that caught my eye:



thanks in advance for any input!

 

[PonderingSage:]

I like the idea of solar greenhouses, Where the north wall is opaque and insulated. It looks like that’s how that would work with your shed in conjunction with the greenhouse.
I’m planning on building something this year too, so I’m interested in following this thread.

 

[newby]

I built a greenhouse (approx 8x10) in Ontario, also zone 5b.several years ago. I am surprised how LITLE I use it- a few weeks in the spring to bring my seedlings along, and to overwinter my hardy bonsai. If I had it to do over, I would just build a good shed and have a small lean-to greenhouse, smaller than your first picture but same idea. Or maybe just a good cold frame!

 

[Fidur]

Here are a couple images that caught my eye:

View attachment 445656 View attachment 445657

thanks in advance for any input!

I would build one of those in the pics just for the pleasure to have such a beautiful place in my garden!!! Just like this from Santafebonsai https://www.bonsainut.com/threads/my-garden-share-yours.30782/post-962438

 

[Deep Sea Diver]

Usage depends on where you are and what’s in your collection.

We use both 8x6 i cold greenhouses most of the year. Yet we have lots of azaleas and trees that need extra protection. During the summer it’s orchids etc and cuttings with 50/70% shade cloth.

There is alot more to think through then basic construction…. especially ventilation, drainage and utilities to name a few items.

Btw there are a couple good threads on greenhouse design considerations here.

Good luck!

Cheers
DSD sends

 

[Dogestoevsky]

Hey, thanks everyone for the replies!
@ponderingsage yes I do believe that’s the way I’d do it — the opaque wall against our north fence, with the greenhouse area facing south.

@newby I’ve had a similar concern, and in the past when I managed a community garden we serially under-used our cold frames and poly tunnel. But I think for me this structure will be 40% tool storage, 40% unheated tree storage, and 20% greenhouse / cold frame. But I DO want it to look nice! Especially with our limited space, it will be a part of our everyday landscape.

@Fidur thanks for the link! I love the look as well.

@Deep Sea Diver thanks for the advice, those are the details that are giving me anxiety . I know absolutely nothing about ventilation or temperature regulation when it comes to greenhouses — just that I need to have them! I did a bit of digging on other shed / greenhouse designs here and will continue tonight. Any from memory that stock out to you, good or bad?

 

[Deep Sea Diver]

You are most welcome.

Check out @JudyB ’s post on her cold greenhouse.

Also this link, especially for drainage.

cheers
DSD sends

 

[JoeR]

I have a lot of experience with passive greenhouse design from both of my business', you're welcome to PM me. I highly recommend researching Chinese passive greenhouse designs and taking inspiration from them. We do not get a lot of snow here, if any, so that is a factor I did not have to consider.

Best, most affordable way to do it: insulated northern wall, double layer inflated poly. Spend a little more on a thicker plastic. If the main purpose is heat in the winter, you can go all out and make the insulated wall a brick heat sink or similar (water barrels, haybales, etc). The Chinese design has an insulated sheet that rolls over the clear side at night, if you're doing a smaller build this would be a great addition. I can recommend heaters as well.

Prefab like the pahlram greenhouses just did not hold up long for me according to the money spent, and don't insulate all that well with single thin plastic walls.

For my living art business I built a 20x40 greenhouse with the northern wall actually attached to an existing building. 3' insulated walls all the way around, and double layer inflated poly- my heaters barely had to run this winter maintaining 55-60 degrees. Again though, we have mild winters

 

[Dogestoevsky]

I have a lot of experience with passive greenhouse design from both of my business', you're welcome to PM me. I highly recommend researching Chinese passive greenhouse designs and taking inspiration from them. We do not get a lot of snow here, if any, so that is a factor I did not have to consider.

Thanks for the input! I’m in 5b is SE Wisconsin, and we do get a fair amount of snowfall — though the lake usually tempers the worst cold of the winter. At the moment my collection is 80-90% native species, so In my research I’ve seen most professionals / advanced bonsai people recommending winter storage just above freezing for hardy species. After confirming with a few people locally, that’s what I might try to accomplish!

 

[Canada Bonsai]

What are your “must haves” in a greenhouse?

The sliding style shade cloth structure at Kouka-en has always been very interesting to me. I like that it is customizable for different zones, and because it reduces the need to move trees around.

I am currently considering doing something similar inside a greenhouse whose 6mm poly covering will be completely removed in the summer. (I put the 6mm poly cover on for winter to keep temps above freezing, again because I rather move structures than move thousands of trees).

All of these images come from 2 current Kouka-en apprentices:

Kaya: https://www.instagram.com/moonlightbonsai/

Michael: https://www.instagram.com/bonsaiharmony/

 

[BrianBay9]

I'd strongly recommend incorporating a heat-sink of some kind. The solid wall would work if it's of sufficient mass and gets direct sunlight to heat up during the day. The other approach I used was to use water barrels to support shelving. The water captures heat and releases it slowly at night.

 

[Deep Sea Diver]

Check out @BigBen ’s Romanesque style floor heat system.

cheers
DSD sends

 

[Leo in N E Illinois]

Most of comments about greenhouses have come from mild climates. Zone 5b winters are no joke. Plan for back up. Plan for at least 3 days without electricity. After seeing a number of (other people's) orchid collections freeze, I decided to winter my orchids indoors, under lights. The house can coast above freezing for a few days, and it turns out that worked out okay (longest I went without power was 36 hours in 0 F or - 18C temperatures). So if you decide on heating your greenhouse, have a back-up heat plan.

Also ventilation - that odd, bright sunny day in late January - sun on a glass roof can heat a space very quick. Have automatic vents, like the wax or oil powered vents, and have fans that can exhaust the volume of the greenhouse every minute. The once per minute will keep a greenhouse at ambient on a 90 F day, which used to be unlikely in winter. Once per 3 minutes is a more "practical" level of ventilation, but can leave you with a greenhouse that needs to get shaded for summer use.

So vents

and back up in case of power failure.

 

[Frozentreehugger]

Like @Leo in N E Illinois . My interest involves the cold regions . Zone 4 a where I live . Been trying to come up with practical . Aspects of a green house for bonsai here . The main part of the equation I have never heard any discussion about . That I’m planning is . To employ the natural heat in the ground . Expanding on the thought that gardeners and early settlers . Used a root cellar to store perishable food for the winter . Idea being below the freezing depth in the ground . There is natural warmth . What I’m thinking is a green house with a basement . . Simple a hole in the ground most likely cement block walls . Insulated . At least 4 feet deep more likely 5 or more . Stone floor . ( no concrete to allow the heat to rise ) some sort of grafted or porous floor at ground level . The conventional green house sits on the foundation wall . This seems to add cost and complexity . But the heat from the ground should help . And the basement will be a storage place for dormant hardy trees . One must consider that in this climate . You must take some avenue . To solidify the construction of a glass room . To account for the ground freezing and moving in winter . . Otherwise you risk broken glass . Other than cost and complexity I see no other negatives to the idea . Please poke holes in the plan . Appreciate any insight

 

[hemmy]

The main part of the equation I have never heard any discussion about . That I’m planning is . To employ the natural heat in the ground . Expanding on the thought that gardeners and early settlers . Used a root cellar to store perishable food for the winter . Idea being below the freezing depth in the ground . There is natural warmth . What I’m thinking is a green house with a basement . .

I remember seeing a picture on the web of Julian Adam’s greenhouse which was built on an old pool. I’m not sure how he handles water drainage. Similarly, would you need a foundation drain and sump system? The “Swedish Skirt” ground insulation method used in Big Ben’s greenhouse is interesting. I’d think you’d need a foundation drain with that system if you were creating the root cellar-greenhouse.

 

[Frozentreehugger]

I remember seeing a picture on the web of Julian Adam’s greenhouse which was built on an old pool. I’m not sure how he handles water drainage. Similarly, would you need a foundation drain and sump system? The “Swedish Skirt” ground insulation method used in Big Ben’s greenhouse is interesting. I’d think you’d need a foundation drain with that system if you were creating the root cellar-greenhouse.

The idea is like normal house construction here you pour a cement footing for the wall which is just a cement base slightly wider than the block wall and build the wall on that . Or you pour a concrete wall on the footing . Insulate the wall . ( I’m looking into a new idea where you build a wall out of product that is a foam insulation block arrangement then you pour cement into the blocks like a mold . The key to the heat rising out of the ground is you don’t seal the floor with cement like a basement . Just crushed stone as I see it to resist mud . There for drainage should be good . You have a valid point that a sump hole and pump may be necessary to keep the basement from flooding but it’s a easy addition in the corner thanks I had not considered that

 

[Frozentreehugger]

Most of comments about greenhouses have come from mild climates. Zone 5b winters are no joke. Plan for back up. Plan for at least 3 days without electricity. After seeing a number of (other people's) orchid collections freeze, I decided to winter my orchids indoors, under lights. The house can coast above freezing for a few days, and it turns out that worked out okay (longest I went without power was 36 hours in 0 F or - 18C temperatures). So if you decide on heating your greenhouse, have a back-up heat plan.

Also ventilation - that odd, bright sunny day in late January - sun on a glass roof can heat a space very quick. Have automatic vents, like the wax or oil powered vents, and have fans that can exhaust the volume of the greenhouse every minute. The once per minute will keep a greenhouse at ambient on a 90 F day, which used to be unlikely in winter. Once per 3 minutes is a more "practical" level of ventilation, but can leave you with a greenhouse that needs to get shaded for summer use.

So vents

and back up in case of power failure.

You hit the nail on the head as far as I’m concerned . The largest problem with a non commercial greenhouse . Or let’s say smaller hobby oriented green house . That is overlooked at the start . Is the temperature fluctuations . Inherent to them and lack of a plan to deal with it . Can be very troublesome in cold climate . Late winter early spring trying to control when dormancy is broken for example

 

[AJL]

If youre planning to protect native hardy species over winter then one simple way to avoid problems of overheating during early spring could be to leave the door slightly ajar during normal daytime just to keep the trees in sync with your local climate and provide ventilation . That is assuming youre at home most days and can remember to shut it up each evening!! obviously your climate in Wisconsin is more extreme than here in Britain but your native trees should be adapted to it....

 

[Bonsai Nut]

Lot of good ideas / suggestions. Just as a reminder:

If you are keeping cold hardy trees in a cold storage area, they don't need light. Needless to say you can't keep tropicals with them. You are more at risk from the space getting too warm than too cold.

If you are keeping tropicals in a warm storage area, they need light. Needless to say you can't overwinter cold hardy trees in the same space.

Either way, the earth is your friend when it comes to temperature moderation. It will keep the space cooler in the summer and warmer in the winter, and moderate the rate of temperature change. A concrete slab will moderate temps much better than a raised wooden floor. A concrete slab with a concrete pony wall will do even better - particularly if you can ramp soil around the exterior walls (waterproof them just like you would waterproof a foundation wall exterior).

 

[Maiden69]

The sliding style shade cloth structure at Kouka-en has always been very interesting to me. I like that it is customizable for different zones, and because it reduces the need to move trees around.

I am thinking about making something similar as well since I saw it first time in a video from Bjorn... I'm in Texas, so overwintering is not my priority. I may need to protect my trees from freezing temperatures a handful of times, my main problem is the heat and the sun. Maybe using the 30% shade during hot days in the winter also help the trees not "wake up" too soon.