Growing Hydroponic Lettuce Outside with No Electricity

I wanted to see what would happen if I moved a couple of hydroponic boxes outside. These are the ones that I built for doing the Kratky method of no aeration. I made a few changes to the first design to resolve the wind issues. Aside from having the boxes fill up with rain water, things went very well. The lettuce is nice and healthy, and this was done with no electricity. The only change I would make is to add some type of awning or covering over the top to shelter the boxes from the heavy rains. A little rain won’t hurt, but downpours fill up the boxes quickly. The fertilizer I used was 4-18-38, the same thing I’ve been using for awhile now.
Here is how I mix the fertilizer:
This is my explanation of the Kratky method:
How I built the boxes:

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