I live in SoCal and planted corn in almost the same way, and my plants are thriving. I thinned them once, but only because I had put two seeds in every hole. Hopefully we will both see corn in a few weeks!
I like how you did the planting bed. I have 8 adjacent, smaller circles of 3 plants each, with a drippers. In the North San Gabriel Valley where I am, it gets hot in my garden area because of the walls and full sun. Did you ever have good luck with two crops in one year? I tried, but the second crop was not so good.
Describe how the trellis on the back wall was built. What is it used for?
The Trellis is for the Winter Melons. See this blog posts:Building a TrellisTrellis and Vertical Gardening