For those blessed with backyard space for a dedicated grow area, greenhouses make a lot of sense. What I have done to make things easy for me was to build a raised bed dirt box and then build a 3-sided enclosure around it. The enclosure is a “modular” construction of stout exterior construction plywood fastened together with angle brackets. If a portion becomes damaged it’s easily dismantled & replaced.
The plastic sheeting can be lower end polyethylene greenhouse plastic or slightly pricier marine vinyl boat window stuff all the way up to somewhat costly polycarbonate panels. Keep this in mind for us Arizona growers : The plastic sheeting/panels will need to come off in the summer unless you want cooked little plants. When it starts to get warm and may be 78F in springtime that greenhouse is going to be close to 100f. Imagine when it gets to be 105F–that plastic sheeting is going to be like a magnifying glass. I pull the plastic off and replace it with 50% shade cloth. Not only does this protect the developing plants from the blistering AZ sun but also provides a visual block so no plants can be seen.
I did a white-wash of the whole unit but in retrospect I believe I’ll leave the inside painted white for reflecting light and the exterior a sand brown for camouflage. Get paint that matches the block wall & soil is a better setup.
I also cut the side panels in half and added hinges. This gives me fold-down sides for easy access for trimming and other plant maintenance .
Affordable Poly sheeting can be found here on Amazon Just be sure it matches your size needed.
To be completely legal here in Az your greenhouse must lock. Anyone who has ever owned a convertible-top automobile knows the first rule of owning such a vehicle–YOU NEVER LOCK IT!!! That’s because a would be thief will slit that top to get in and that alone is easily a $1000 ding right there. What I have done is to anchor the material at the bottom with bolts through grommets and at the top I have the material attached to a wood brace that locks to the top back. If a thief wants in they must commit the crime of “breaking & entering” by slitting the CHEAP poly sheeting or the shadecloth. That’s the reason the law has specified a locked enclosure. But as the old saying goes, locks only deter those that are honest.
Let’s face it, to what degree can you truly fortify a greenhouse in reality? There is no legal guidelines on construction minimums. You can’t be expected to setup a translucent bank vault in the back yard. Greenhouse have glass panels, poly sheeting, vinyl sheeting or polycarbonate panels.
A tapping hammer will defeat a glass panel, a carton knife defeats poly & vinyl sheeting and a propane plumbers torch or stouter knife defeats polycarbonate panels. The thing is–the cops are just DYING to make a bust here & there and an UNLOCKED greenhouse is an ILLEGAL GROW according to Prop207.
The piece of fence board was $2.60, hasp was $3.50 , lock was $8 , carriage bolts & nuts were about $2 so to be in legal compliance was a tad over $16. The material is easily removed & replaced
What if it gets REALLY cold?
Even here in AZ it’s a legitimate question. I like to get an early start on the growing season and that means having to deal with hard freezes at night. I have invested a couple of bucks into these handy items. They are mason jar tea light holders. For “stealth” purposes I painted the glass on mine a flat black to the illumination doesnt show up readily at night giving away the greenhouse contents. You can get 8 hour tealights from amazon. In the enclosed greenhouse that does give you some frost protection the heat from the candle is juuuuust enough to keep the air above freezing. I do 2 in my space and they work like a charm.