check the sunrise sunset times for your area. mid march where i am and many others are at about 12 hrs daylight, so in your greenhouse you need to provide supplimental lighting for another few hours. also be warned when you get rid of the light, that the cycle you had doesnt differ too much from the outside cycle, meaning; say you turn you supplimental lighting on for 5 hrs after sunset, so its on an 18/6 cycle. The daylight hrs outside get up to 14 and you feel you can get rid of the supplimental lighting. well that drop from 18 hrs to 14 hrs will cause your plants to flower. It'd probably be best to keep your cycle going around 14, or 14.5 hrs, then get rid of your supplimental lighting when the daylight hrs are at 14.5. which would be right around the 1st week of may where i am. you follow me?