Container gardening or regular gardening? Please explain why thoroughly.

I am setting up a patch of land in my backyard for gardening. Right now I am going to be planting sunflowers,sweet corn, cucumber, radishes and green onions.

On the back of a few of the seed packets it says something about planting the seeds on a hill.

Is that I think it means? Like you make a row and a little hill all the way down the row?
Thanks all! Wow, I am so sun burnt and sore from tilling the ground. I will make sure to make little hills though!!

Here’s the deal, I live in a town house, and I’m not allowed to plant a typical vegetable garden, so I want to do a pot garden, I did one last year, but it didn’t work very well. Any tips? Thanks!

My backyard has an inconvenient slope that directs water at my basement and is too steep to plant anything. On one side it currently has a 4′ lumber retaining wall which is rotting. I’d like to replace it all with a series of smaller masonry retaining walls to improve drainage and allow for a vegetable and herb garden.

Any idea on where to find resources to help me plan this venture out?

Would Highly toxic insecticide (I don’t get why people still don’t understand these don’t work) contaminate the soil around it? Would plants absorb the toxins? Also, would any of these toxins be found in the fruit/vegetable that the plant produces?