My potatoes grew to about 3 1/2 to 4 feet. Did you put 4 whole seed potatoes per square? I ask this because you are suppose to cut up a seed potato and put one eye per plant....so that would be 4 eyes per square foot.

From what I understand, first time gardener here too, that you harvest them after the flower blooms, for new potatoes or small potatoes, and after the plant totally dies for the larger potatoes.

If you put new seeds potatoes in after you harvest the plants, I dont think you will have enough time (depending on your zone) to grow another harvest of full potatoes. I wonder if you will even get the smaller potatoes.

Are you continuing to put more soil or hay or straw on the plants? If you put more soil as they grow, then you will get a bigger yield of potatoes when you harvest.

I hope that helps some!

Here is a link that might be useful: Jen's Victory Garden Blog

Let's see. I think you overplanted, though depending on the size whole potatoes are fine. I don't cut mine. Spacing for potatoes is 1 per SF I believe. Mine are going on 3 feet and definitely shading.

Depending where you are it is possible for two crops. If you can do 2 tomato crops then go for it. In zone 4 I'm not certain you can pull it off. Good luck!

Here is a link that might be useful: Sinfonian's garden adventure