It's not set in stone, but it seems like 3rd run soil and the Frankenstrains get along best. 4th run soil needs to be cut with something. Fresh promix works for some....and I hear there's some loosely associated misfits and ne'r do well's using a bit of.....
Coco!
I believe a bit of coco will help with salt and mineral buildup that occurs with soils that have been in service for several generations. I haven't done this but I'm hearing from a few and it is working for them.
Interesting. If I ever try it I'll be sure to journal it.
I've got 3 Skywalkers about 4 days into bloom that are in 1st run soil. I haven't added blood meal yet, but after their initial Transplant watering, I top dressed epsoms which have yet to be watered in. My plan this time is to build as much of a root system as possible by growing in clean, 1st run soil and begin to introduce the high PPM, high energy soil later in bloom, about a week before the Cat Drench, which I'll tone down a bit due to the blood meal and WayAhead.
It will be the third time through with the strain and hopefully I can get it just right. The last harvest was excellent but I felt like I could take it to another level with more familiarity.
Hopefully, all this rambling gives you a bit of insight into how I am currently thinking about these strains. Thankfully, I have that gassy "OG" thing in a huge way with the Lemon Paki. Otherwise, I'd really miss what many consider to be the finest smoke......a really well grown OG type. It's hard to argue with them, really. It's damn good.
Oh....on edit: the soil is nasty after a run. I don't recycle it, which is why I llike 3rd run most of the time. After running a tray with bloodmeal, I've always got more insect pressure. First run soil puts things back in balance.