Swiss chard is a great vegetable to grow hydroponically, comes in six different colors making it an ideal vegetable to enhance food appearance and nutrition. Each color has a slightly different taste, some are sweeter and others are a little on the bitter side to accommodate various pallets. 

When grown in hydroponics leafs can be harvested for months as long as you leave some leafs each time you harvest. 

I personally prefer the white it is sweeter than the more common red.