Help how do i know when to flush and can i snip top buds?

Hi Every1 i really need advice im completely new to this i got 2 thats near 4 weeks in flowering stage at the moment but do not know when to start giving just water - my girls r in soil and they only under a 250 wt but my other problem is the top buds on 2 branches have grew above my light - don't ask me how i dont know, but its impossible for me to move the light any higher because of the space they are in and cos i only got small light its struggling to reach bottom buds as it is and i need to know if i cut them off would i damage the rest of the plant? Please guys any advice u can give will be much appreciated. I don't even know what strain they are n 2 b truthful dunno how they doing so well as i had them from cuttings in a matter of emergency and not havin a clue how to raise them iv been reading things and hoping for the best but now i have got them to this stage i really don't wanna mess up now Thanx

The more specific you can be the better an answer you will receive. Personally if its a space issue you should try to control its height during your veg stage try keeping them in smaller pots (at least 6 weeks if growing from seed) or until their mature. They will continue growing taller in your current stage(Flowering)as you are observing now. You dont need to clip them! well you can if you want, but be creative...go buy a 23w(23w because it has the 2700k spectrum which is close to the red color the MH puts off) cfl 2 pack from an appliance store and place these lights near the bottom of your plants..that should help give light to the lower portion of your plant(s) and with cfl's they dont emit as much heat as a MH/ Hps so they can be nearly touching( without touching )spend the $10 for the bulbs. As for flushing, Rule of thumb is the last 2 weeks before harvest...Depending on the strain you could expect at least another 2-3 weeks before needed to cut off nutes/flush/water only.. I also suggest a microscope($12 at radioshack) to check the trich's for that milky-amber mix. I hope I was some help to you...
For your buds that are growing above the light...sounds like the main cola/(colas) if you topped your girls id hate to see you chop them since 4wks of flowering means they are not at their full potential and you will be upset with your quality of smoke and taste...they will not die if you clip the buds off its called "taste testing" DONT damage the stem that gives the life to your buds and Harvest properly...


Patience is the key

thank you so much

if you have the horizontal space and your main stems are still flexible enough you can try bending the stems that are too tall and holding them down with twisty ties, be careful not to snap them if you feel them start to snap my advice would be to stop although some people insist that even a damaged stem is capable to transporting enough nutrients to produce a decent flower. Try to avoid cutting the main colas as they are usually the most productive. To avoid this next time look into weaving the plants in a net during veg cycle.