When To Start Using H&g Root Excelerator

[Florida61]

I'm popping some seed and was wondering when to start using the excelerator on them?

 

[scarecrow]

I'm popping some seed and was wondering when to start using the excelerator on them?

I guess it would depend on what medium you are using for the seedlings, but for an inert medium (coco, or peat) pretty sure any time once roots are developed. For soil, id say it depends on whats in the soil and for how long.