Would like to grow cabbages. How many plants do I need for 1acre? I would like to plant red acre cabbage on 1 acre piece of land.
The number of plants needed will depend on so many factors -- soil and other growing conditions; cabbage variety; climate, to name just a few. Here is an article giving you an idea of what you need to know about: https://www.gardeningknowhow.com/edible/vegetables/cabbage/growing-cabbage.htm
I suggest you seek assistance from the nearest agricultural station or university with an agriculture dept.