I‘ve had ceramic braces since November last year and I‘m eating oranges right now.so I‘m just wondering.And by the way, I know that it‘s not the BRACES that actually stain its the liga-something or somewhat .
Top soil with a little bit of fertilizer
Any commercial potting soil, outdoor soil is too heavy.
I buy a couple of the largest packs of compressed compost sold by B Q every year and use it for everything which grows in pots, tubs, window boxes and hanging baskets. My herbs do pretty well - I have some in a hanging basket which I take boating (hang them in the pointy end of the boat) Mint does well, just in water. You can also grow Basil by breaking off about 3 inches of a shoot and putting that in water till it grows roots (just a few days), then pot up.
Oranges will stain the braces and the elastic very badly
Ceramic braces do not stain with oranges but if you have the rubber rings holding the wire in the bracket , these tend to discolor with food , tea, tobacco, wine.