What is good to grow in March?

[shiva]

just be careful with tomatoes or any veggies in March, depending on where you live you could have that random cold day and freeze your veggies and they die.

Using a greenhouse can solve several problems, but Tomato plants survive in most seasons here. I agree with you for climatic conditions that can freeze plants.
I have successfully grown tomatoes in the past, now looking to move into Hydroponics.