gently place the seedling tap root down and gently push some soil in around it and then cover it gently with some more soil ( make sure you use regular potting soil with a decent amount of peril it in it..I like shultzs potting soil) spray (water @ 6.5 ph) the soil till it’s dark and wet but not puddling..place the potted plant under a 1300-2600k daylight (for vegging cycle) CFL..about 3 – 4 inches from the pot ..in about 2 days or less you will see your new seedling popping through the soil..if it takes 3 days I will be surprized..keep checking the seedling about 3 times a day..make sure to fine mist spray the soil and keep it dark..as the light will dry it out..don’t let it dry out until your plant gets about 4 inches and has its first real growth leaves..
the best thing is to let the seed develop a tap root to a length of about a half inch. I am also going to recommend and assume that you knew enough to let the seed(s) bob around in a glass of water that was allowed to sit for a few hours (to allow chlorine to gas out of the water. before putting the seeds in). and then put the glass of water and seeds into an empty drawer somewhere where there are no lights..and leave it there for 12-14 hours.."longer will risk drowning the seeds"..then you should have triangle folded a and dampened brown coffee filter..not white..white ones may contain bleach..which is also chlorinated..put the coffee filter triangle in a small tray and put the seeds very gently onto the filter.."don’t squish them or they will die"..after their soak they are delicate..so do this carefully..put a "once folded" coffee filter on top of the seeds..and wet it ..
you will see the outline of the seeds through it slightly once it’s wet..put the tray back in the drawer and use the water in the cup to wet the top filter a couple times each day..DO NOT LET THE FILTER DRY OUT BUT ALSO DO NOT LET THE SEEDS SIT IN A PUDDLE..after about three days the tap root will be around a half inch on the seeds..if not leave them until they are..once the seeds are ready..plant them each in their own small 4 inch pot by poking a whole down about an inch with a chopstick or your finger..
Other people in this thread seem to think that it’s a good idea to plant the seed as soon as it cracks..however this can be a bad idea..the tap root is what gives the plant its early root structure..and strength..allowing them to have this before planting gives the seedling a much better chance to survive any problems it may encounter in the soil..remember..soil is a living organism and has bacteria..a seed may get halted in its early growth by encountering any numbers of chemical reactions including chlorine shock..pests..or fungus..the ones with a half inch tap root..seem to be able to cope better..
Then water the soil as you would with regular plants..allowing the soil to almost dry out up to an inch below surface..I usually water when I see the edges of the soil pull away from the pot sides..but for the seedling when it is still just in the baby leaves..keep the surface damp ..by watering or checking it every few hours..keep a light breeze (fan) circulating in the room..not directly on the plants though..especially when they are little. good luck
Now gently extract the seed from its original home with a pair of tweezers making sure to touch only the shell and not the root (the root is the most sensitive part)! Now lay the seedling in the middle of your newly split open Rapid Rooter and gently close the plug around it again.
The first thing to do is get a new Rapid Rooter. Since your seed already has a relatively long root, cut the plug open lengthwise so you can gently place the seedling inside in the right position without having to "push" down on the seed.
Most seedling plugs will go back into place easily, and you'll barely be able to tell it's been opened 🙂
If your root is growing straight up like in the picture below, it's not good. This is most common in seedling plugs. The tender white root tip has a good chance of drying out or being exposed to too much light. You want to strongly consider doing some "plant surgery" to turn this little seedling around to the right direction 🙂
Is your cannabis seedling growing upside down? Has the tap root come above the soil?