Sunny back garden in Houston

I am a pensioner living with my son. I have mild mobility impairment and have difficulty maintaining a large garden. My son works from home and looks after the house and my finances. I spend most of my time visiting my wife who is cared for in a local nursing home. I would be happy for the whole garden area to be used for growing vegetables. There is someone in the house 24/7; my son and I visit my wife in separate shifts. There is a greenhouse that may also be used for growing and a shed with an assortment of tools; I haven't listed these tools because the shed is too cluttered for me to check what's in there.