First Garden suggestions, Greenhouse or not to greenhouse? | Vegetable gardening | Commercial Hydroponics farming in India

I live in Cape Town, South Africa.
I have cleaned a section of my back garden to start a veg patch.
I need help from the community to decide if I need a type of greenhouse or not.
The patch of ground gets about 10 - 13 hours of sun everyday.
The temp here is anything from 20 to 35 degrees Centigrade.
There is a bit of wind coming through. but I don't think that will be a problem.
The sand is quite dry and compact.

I know the basics of growing my garden. I started off with some tomato plants in a big vase near the garden patch. At first they seemed to grow quite well. but lately the leaves seem to be going brown, even though we water the plants daily.
I had pictures to show, but apparently I can't add them here.

It was suggested to me that I should build a type of greenhouse to block the sun for part of the day and to block the wind as well.
the plan was to build the roof with corrugated plastic roof sheets and the walls to be done with shade netting. (to help keep the birds and bugs out as well)

At a later stage I could add a misting system for the greenhouse. (when I have the money)

I plan on planting rot and leaf vegetables, some herbs, climbing veg plants as well.

Do you think I need a greenhouse or would the garden work fine without one?