flimsy cold frame

Today I made a lightweight cold frame to use as I harden off my transplants.  It was really easy to make but turned out rather flimsy.  So here is what I did and at the end I will tell you what I am going to do to fix it.

Necessary supplies: 4 foot lathe, metal fasteners, a square, a hammer, 3.5 millimeter plastic, scissors, and a stapler.  So I used a square to make sure my angles were good before pounding the fastener in with a hammer. 

Here is what the fasteners looked like before and after.  The fasteners were rather sharp but I found them easy to work with even with kids around.

Then I cut off the amount of plastic I needed from my roll.  And attached it using a stapler -- I have a heavy duty stapler somewhere but couldn't figure out where it was when the time came so my desk stapler had to do.

I think this modest cold frame will be enough to keep my transplants protected while they harden off.

But my cold frame is a little flimsy.  The wind threatened to take it away so I put a chair in front of it for the time being.  When I get a chance next week I am going to buy some 2x2 and attach it to my frame for greater stability and heft.  I don't think a mild wind will down it then.

Still, I am wondering if at this point if it would be more time efficient to just try direct seeding into the ground.