With the price of lumber; is 2x3 pine sufficient for the frame of a 7x14 greenhouse.

Short answer, No. Add the weight of the greenhouse to a little wind and I suspect you will have a pile of kindling. Look into metal pipe construction.

I was planning on anchoring it with auger style ground anchors. Thought that would secure it sufficiently. thoughts?

Yes, you must anchor it to the ground but the build must support the weight of the building too.

Hi @Trobaugh and welcome!

My greenhouse (prebuilt Sunshine Gardenhouse) is constructed with redwood 2x2's but there are metal braces at every joint. The 2x2's support all the polycarbonate very well, but it is the bracing (and anchoring to foundation) that keeps the greenhouse sturdy and strong.

Here is a pic of one of their smaller greenhouses. You can see the bracing. I would not attempt a 2x2 greenhouse without customized bracing. I would go with at least 2x4's and even then I would use bracing or built a metal structure as Daisy recommended.



Let us know what you decide.

I think it would depend on the design and construction methods used for the greenhouse; but if you are thinking about a 7x14-foot size, you might want to consider something like this -
https://www.ebay.com/itm/39226...

I bought 2 of them some years back (7x15) and the frames proved to be surprisingly sturdy; I eventually re-covered one, after the original covering deteriorated from the sun, and converted the other one to a "hoop trellis" by covering it with "remesh" (concrete reinforcing wire).

This is what the re-covered one looks like:


Of course, what you put up also depends on how you intend to use the greenhouse, and what the climate is like where you live!

Probably depends on how far apart the supports are spread. Keep in mind home construction has been done for years with 2x4 construction with studs 16" apart. The loads are probably 3-4 times your GH will ever see. I think you're ok with 2x3's but check out sites like sturdi-built and cedar-built greenhouses, i think they use 2x3 construction. Bracing may not be needed but eliminates bad joints and foolproofs the build. A skilled carpenter would probably skip the braces but a hobbyist might be better using them. Make sure your ground anchors go deep enough to prevent frost heave. Good luck with your build.

Jim, I don't think this is necessary - "Make sure your ground anchors go deep enough to prevent frost heave." I use the auger-type anchors on the 7x15 hoophouse in my photo, they're probably only a foot or a little more into the ground but have never heaved out due to freezing. (they may be the one thing around here that hasn't - the deck on our house is another story!)

Weedwhacker said: Jim, I don't think this is necessary - "Make sure your ground anchors go deep enough to prevent frost heave." I use the auger-type anchors on the 7x15 hoophouse in my photo, they're probably only a foot or a little more into the ground but have never heaved out due to freezing. (they may be the one thing around here that hasn't - the deck on our house is another story!)

I hope your right, I've never experienced frost heave but have been warned about it many times. I have a plastic 10x10 shed on a 2x6 platform with anchors like yours and never had an issue.