bamse

hi beth here can you advise me on how much space i need for 4 plants which have gone just one week into flowering stage. plants are around 2 feet tall now and i have a space about 5 foot wide by 5 foot high is this enough room and the plants are growing under a 600w HPS lamp and seem to be thriving.

Normally you would want to do the topping during veg in order to create new branches and bud spots. You can start topping at any point during veg and it should be O.K.
Its better to leave the plant when she starts flowering to prevent to much stress.

Hope this helps.