Could be older beans? Just assuming, someone correct me if I'm wrong.. As an example, the Orange Creamsicle x Western Grail seeds that were sent to CC (made in 2020) didn't make it whereas the fresher "Highlander" Freeze 7 seed did.. but that could have been environmental also.. It's tough sometimes, seeds get off to a rough start.. but with time in the proper environment, they usually come around. As long as it's nothing like fungi or bacterias in the soil that inhibit growth.. that's another story.
How did the seeds look? A humidifier and heater are a couple helpful tools for keeping the environment stable for plants.. an oil filled heater lasts longer (I think) and is considered more safer than forced air. A diy humidifier is a fun and simple project that gets you lot's of humidity in a relatively short amount of time.
5 gal bucket,
4" fan,
3 disk mist maker and float setup to an inkbird (or similar)
humidity controller. You can also cut corners of ziploc baggies and place them over each individual pot (if small enough) to create lil humidity domes on the fly, works well.
That is great news to hear the plant is making it! The purple jelly (thin mint x jealousy) was a super nice plant and combined with rainbow belts, she should bring some terpy frost with gas on the backend, usual for Seed Junky's strains.. The harvested flowers have been curing nicely and the PJxRB cross is my favorite to open. Peace bro! Happy Sunday