That would not change the appearance. Neither will paint in the water. Do a search on this web site for dyes or colorant. I think there's a large thread about it. I prefer "au naturale" and just paint or stain the outside.
They sell "buff" (a light tan) cement dye at Lowes or Home Depot. Follow the package directions for the dye. If you put in too much colorant it will affect the cure.
Don't go with too large of a pot/trough at first. It does take a little practice and I feel bad for people starting out that have failures.
Your cement mixture has to be on the dry side. If it's too wet you'll have a hard time keeping the walls from sliding down. I had one a long time ago that started with a 2" thick bottom but by the time I got done the bottom was about 4" thick. Billie

Billie's right. Tea wouldn't make much of a difference and it would fade pretty fast, too.

Ask around at your HD and Lowe's to see if you could buy the stuff that they add to paint, it is a very dense colorant. HD here used to sell it in small cans, but I haven't seen it lately.

Plan on playing around with colorants to see how each type works. Paving stones would be good 'canvases' to try them out on.

Commercial and decorative concrete places may also be a good source. I have heard that the warmer colors (reds, orange, yellows, browns) hold their color better when exposed to moisture (even when sealed) than the blues/greens do. Talking to people in the business of decorative concrete (more all the time) can probably give you some very handy tips.

Sue

We have been playing with hypertufa and we just dyed a "batch". Lowes and Home Depot have basic colors but a masonry supply stores have a huge color selection. My question is....if dyed will these pots bleed dye onto decks, etc?