Hey everyone. I am wanting to buy (or most likely build) a greenhouse come spring. Looking for a design that would be low cost up front. Any Ideas? Thanks everyone!

In Michigan, low cost is not first on the list!
You need to decide what you want to grow, how much space you'll need and how you are going to heat it! Wind chill in Michigan can cause fits with your energy bills.
A lean to of some type placed along the south wall of the house is a good way to start.

I would start by finding out what the laws are concerning structures in your yard or attached to your house.

In my area, if the structure is free standing, there are no laws. But, if the structure is attached to your house, it must have a foundation 18 inches deep, and be able to withstand winds of 130 MPH.

My greenhouse is a lean-to on the south side of my house. It has an aluminum frame and super 5-wall polycarbinate glazing. It has withstood winds of 90 MPH. Mine is heated with thermo-solar panels but, if they are covered in snow or the sun doesn't shine, no hot water = chilly plants so I have a small electric emergency heater and a nature gas 'burner' that hooks into the thermal system. Our lowest temps are usually around 10 - 12F.

I do have friends who have built free-standing greenhouses and they last until we have a Zephyr, and then they are gone. So, even if you don't need a permt to build, I would try to follow the building laws for structures. And, common sense should tell you that a single pane of plastic or glass is not going to hold any heat.

Without some kind of supplimental heat or a heat sink, the inside of the greenhouse will be exactly the same as the outside. When I lived in CA, I had a twin wall polycarbinate greenhouse that I heated with 4 heat lamps. I set them 4 ft above the floor facing down to heat the plants below and the heat from the metal hoods radiated to heat the space above them. Our temperatures were in the mid-20's and I managed to barely keep the greenhouse in the 50's.

My daughter has a twin wall lean-to "temperate" greenhouse in zone 6a that she can maintain in the low 30's - high 20's (her lows are closer to zero) with a small radiant heater. She is growing citrus trees and azaleas and a few cold hardy orchids. I am growing tropical plants so try to keep my greenhouse above 50F.

So, as Bill asked, what are you planning to grow? Extending your vegetable growing season? Tropicals? Temperates?

An attached greenhouse on Long Island raised my taxes as it was considered a "permanent structure" The foundation had to be 36" in order to prevent frost heaving.

My first greenhouse was an 9 X 12' freestanding model. I installed it with a wooden foundation.Local ordinances considered it a "storage shed" and there weren't any new taxes involved.

Thank you for your responses so far! As far as nit going cheap on the green house, i would love to build a permanent green house, or purchase a kit at that. However thats not in the cards for me at this particular time. I am just starting out and want to see if I enjoy having a green house with little invested before I go "all out".

I would like to not be judged right off the bat here... the reason for the greenhouse will be for growing cannabis. I am a disabled veteran (USMC) and am going to see if I can grow my own plants for medicinal purposes. Basically, I dont want to take 10 pills a day (at the age of 29) for the rest of my life!

The main reason for the greenhouse is that I am interested in growing Sativa dominant plans (which offer more medical benefits rather then a "high" feeling). The problem is that Sativa based plants flower and bud later than other cannabis (Indica) plants. With the best time to harvest being late September to mid October, the reason for the greenhouse it to provide the best enviornment for the plants as it starts to cool off. Hey its Michigan, anything could happen!

Anyways, I hope im not judged because of my intentions. I do appreciate any/all help and advice!

Hi NewRy,

There won't be any judgement here - I live in Nevada, the "anything goes" state.

If you are trying to extend your growing season a month on either end of the summer, your greenhouse will be a much easier build than if you are trying to keep orchids alive. Do you have access to power? You will need fans for air circulation and a heat source (otherwise, the greenhouse will be the same temperature as the outside air). Think about putting a spigot nearby (or inside) so you can water without dragging hoses.

There is nothing wrong with a wood frame greenhouse but remember, wood, even chemically treated wood, will rot in 5 - 10 years depending upon how wet and humid conditions are. I would suggest the floor be gravel with bricks or stone pavers on top for good drainage. There's nothing worse than discovering you are gardening in a swamp and you won't have to worry about rotting wooden floor boards. You can build a foundation with concrete deck piers buried in the ground. The best glazing will be something polycarbonate - twin wall may be all you need.

No judgement here either NewRy.
Hope you have much success with whatever you choose to do,

And Thank You for your service!! 🇱🇷

Thank you for that BigBill! I was actually thinking of a standalone building such as you described above. Something moveable but built with a wood floor. Im thinking I may just start with a strain that can grow outside that has a cooler range in which it can still flourish.

No judgement here either. It sounds like what you want is definitely feasible. I grow tropicals in my GH, so I have to heat it to 60 all winter. Definitely check on your building codes and make sure it will be built so it doesn't increase your property taxes. They're high enough for all of us.

It sounds as if you have your growing season figured out so you should be fine.

A couple of things you want to keep in mind about your cannabis:
- It can withstand cooler weather. It doesn't need to be kept at a tropical temperature all the time. It can even take a light frost or two.
- A green house will amplify some of cannabis's common problems due to the warmer, moister conditions in the house. That means you have to be ready to deal with issues like fungus and spider mites.
- There are varieties that flower early and therefore are better suited for an "outdoor" environment. Our lovely Canadian neighbors probably have some good hybrids that you might be able to access in your state.

If you want a truly cheap, easy to set up and moveable structure you might look into a hoop house. I don't know how it will perform temperature-wise in your area, but it might be worth considering. NMSU has plans for a simple hoop-house online: https://aces.nmsu.edu/pubs/_ci...

Good luck and thanks for your service and sacrifice

@NewRy, If you look back thru some of the old threads you'll find all kinds of ideas, underground, sunken, and reused material. There is a thread that includes all kinds of improvements to a relatively inexpensive Harbor Freight Green House. The thread "Harbor Freight Greenhouse projects" in Greenhouses forum Even if you're not investing in one the ideas are there to adapt as you may. You may get by with something as simple as a lean-to with removable ends to control summer heat.
Fratres in armis

NewRy, I am a Michigander too, zone 5 (5b I guess is the new terminology). Don't know a thing about cannibis but with a nephew that suffers from PTSD (Army) I can understand your need. And BTW, thank you for your service! I am in the throws of research for building my own greenhouse and one book that might be of interest to you is Mike Oehler's "The Earth Sheltered Solar Greenhouse Book". That lovely polar vortex we just had was a rude reminder of just how cold it can get. He was located in northern Idaho and had 20 below temps too. I got the book on my kindle for about $10 (couldn't find it at the library). Easy reading and he also tells of his errors as well as his successes. I think you could get a good idea of how to put something together cheaply and easily for a good trial run to find out if you liked it, without getting too involved. At the very least you could extend your season. Have you considered cold frames?

Michigan fall season extender; I might try a fixed white, insulated E_W wall, with half a hoop house extending to create your protection. How tall or perhaps a more cold frame size depending on the height of your MMJ strain.

If you need more extension, first use insulating blankets of some kind over the film and rent a ditch witch type trencher and put some EPS or other foam board around the grow area; the cold surface earth will suck the heat out of your protected growing space. This is a lot more important for a small hoop house. Wet ground is a good thermal conductor and poof, there goes your warmed soil withing a few feet of the border.

I'm a legal medical mmj user myself, for MS pain and epilepsy. I use the high CBD/low THC stuff, very hard to find in AZ. My liver and gallbladder were wrecked by 20 years of conventional anticonvulants, and I can't handle them anymore, so it's been a lifesaver. It's well tolerated and my low dose is well below a high, which just makes me paranoid. Ticks me off that the rules for growing what I need are so outrageous, even though I'm out in the middle of nowhere. 10 foot walls or a secure locked facility, and annual fees and documentation that are downright abusive.

I didn't know that about growing your own mmj. Are those your state laws or federal laws?

AZ state laws. Medical MMJ was a public referendum, and the state government has done everything to make it difficult, restrictive and expensive. For those of us who are mostly shut ins, it's especially cruel, as the license for someone to pick it up for you is $250/yr and requires registering at the county police department and getting fingerprinted...and they can't be paid, and must sign papers saying that. I haven't found anyone willing to do that. You can't grow for yourself if there is a dispensary of any kind within 25 miles. There is not one state dispensary licensed to ship to you. The small town dispensaries don't carry high CBD, low THC because besides me, they say no one wants it. Alas, pure CBD oil doesn't work at all for me.

Darn, that bites, Bruce. We have an AZ place, near Scottsdale, but we're not familiar with those laws. Sorry we aren't there full time anymore, or we'd help you. I'll have to see what the NM laws are. We have neighbors growing it without any restrictions that we can see.

plantmanager said:I didn't know that about growing your own mmj. Are those your state laws or federal laws?

plantmanager,

100% State (hopefully federal soon) Recently we (Michigan) have legalized recreational marijuana. Along with that came the home growing section. We are allowed to grow 12 plants per residence! I'm going to shoot for a CBD dominant strain as i don't care about the THC. Hopefully I can manage a setup so I can grow year round (12 plants at a time).
Going to be making organic/raw homemade cbd oil with probably 90% of what i produce (10% to my old man to enjoy the old fashion way 😉)

NM is now considering the recreational stuff.

I hope by the time I get my greenhouse built this year, things will change. I'd love to try the juiced leaves- that has no THC but is supposed to be helpful. My biggest need is really for fresh greens and vegetables without glyphosate. It wrecks my guts.