A timelapse of four containers growing crystals from the National Geographic Mega Crystal Growing Lab. The sequence was shot over two weeks (one frame every four minutes, running at 60 frames per second).
It should have taken less time. They recommend a growing area that is at least 68 degrees. This shouldn't be a problem with most of the country suffering record temperatures under heat domes if not actively burning in record breaking wildfires, but San Francisco is experiencing its coldest summer in more than five decades so two weeks seems like the minimum.
Other than not attempting to grow crystals in San Francisco, the other lesson learned is that you really want to use the two silicone cups included in the kit. We tried a pint glass that just grew fuzz (possibly due to the age and pitted nature of the glass) and a jam jar that grew cute small crystals that then made a decent attempt at escaping down the outside. I think three weeks and it would be a full J. G. Ballard situation.
Updated 2021-09-04 18:54:
Second batch. This time shot from above. It's still cold, so this is three weeks, 5 min interval and 60 frames per second for the timelapse:
Updated 2021-09-12 12:57:
Third batch. We're well into September but San Francisco is still bathed in fog. This is still at 5min per frame, but only took two weeks as I moved the lights closer in. For this timelapse I experimented with Adobe Super Resolution so the video has the same sequence three different ways (I wrote a separate post on the Super Resolution experiment).