The salt crystal gardens continued growing, without any additional ingredients for several days. Eventually, they began to wilt a little.
Here again is the progression:
our seed crystals came out SO small that we couldn't work with them.
So we're going to try melting them down (just that little spice container was three bucks)
and start over. I found, and then lost, a link to tips for growing better crystals.
When I find it again I'll add it here.