Yes, you have to figure something out with regards to fertilizer, a little every month will go a long way. Could you keep a pet rabbit or a pet chicken or a couple of quails to use their manure?
Yes, growing 2 or 3 crops very closely together and one might not get enough sunshine. Maybe you can cut a few old leaves off the bigger plants to let more air and sunshine in?
I have a wild rabbit that isn't helping.
I just threw things together this year. Adding the peas to the corn, I was thinking the peas would take off much quicker than the corn. That wasn't the case.