Just put the seeds in 3" square nursery pots with the same soil I use in the final pots. It's the soil listed at the beginning of the Easy Organic Soil Mix for Beginners thread and I mixed it last season . The only thing that worries me is taking the germinated seedling out of these pots when I pot up to a 1 gallon pot or the final 17 gallon pots. The 5/16" red lava rock in the mix causes the soil to fall apart easy when removing the seedling from the container. Just be careful I guess
what size of pot do you use for the seedling? I use to start seeds in between paper towels, then establish them in a solo cup with whatever soil I was using, Transplant to a 1.... then 3..... then finally 7. Now I skip the fuss and extra stress of transplanting and go straight from solo->7 gal Geos... or 10gal depending on the strain.. and they seem to grow like monsters throughout all stages of life I found that by the time the seedling/clone was packed with roots on the bottom the soil had all been somewhat compressed. If you are using the guide and used peat moss it should be able to compact fairly well even with the lava rock. Just give it time.
However I have never personally used lava rock...but i cant think that 5/16ths is going to be enough to not let the soil compact
I'll let the 3x3x3 inch container plants hit near 12 inches tall and by then they are nearing root bound and have a secure bundle of roots wrapping the cube.. Inverted with a slight push on the bottom they simply slide out with zero root disturbance.. They'll run in a 5x5x7 pot till they hit 24 inches or so then it's a last transplant to a 5 or 20 gallon SIP or ground site outside.. This is my set of clones for the summer run.. That left hand tray is very close to needing transplanting as they've reached 12 inches and need watered daily..
I like putting clones out each year. What we get indoors is completely different than what you get outdoor. I take it you are doing containers out side?
I started mine 3 weeks ago . They're in solo cups on a canna regiment, I can leave them in the cups for at least another week and then into a 3 gallon of my soil for another month, then outside into 15 gallon smart pots. It's my first year going outside, I'm excited to get it under way Best of luck on your crop this year man
Looking good my friend. How many sizes of containers do you go through before the final pots? I was thinking of going to 1 gallon (.7 gallons actually) and then into the 17 gallon.