How long does it take to grow salt crystals

I poured salt into boiling water and poured it into 3 plastic containers for about a day but nothing happened I added red dye to one of the containers and banana flavoring essence and one I didn't put an additive in it, how long does it take them to grow

Crystals will form as the water evaporates.... if you put lids on the containers, you won't get crystals to form. A better idea would be to put some of the saltwater in a shallow tray and place a rock in the middle...the water mixture will "wick" up on the rock, and evaporate, leaving the crystals behind.

..........I get why you'd put red dye in one, but why banana flavoring? I doubt it'll taste good... ;)