cool in ur case because ur in the shed ,move the light 3 feet away and turn on the propergater cause at this stage of life roots are more in portant,thye dont need mutch light yet but will gane nice roots if propergater is on as soon as u see them stech lower the lite back to 18in cause by then the can handel it .go to ur pet shop and by two fish tank lights 2feet long 20w for promoting growth they are cheep and u can just put them staight on top of the prpergater they dont burn nothing,soil is cool just dont over water make sure u have good dranged.