In regard to your question on Thinksaymakedo's thread about sexing plants before they flower:
Your best bet would be to just keep them close until they start to show sex.
They will show long before they start to flower.
You will be able to tell your males (which usually show sex earlier than females) because they will develop pollen sacks. They just look like little clusters of balls. If you see these on a plant, then kill the plant that they are on.
The female pre-flowers will be two very small hairs that pop out of intersections where branches come off of the main stem, and also at the top below the highest set of new leaves.
You have to look close for it, they can be hard to see.
Spacing them out far enough that the females won't get pollinated is almost impossible. The pollen will travel a very long way, and it doesn't take much wind to carry it.
I would just keep them at home until you are sure you have gotten rid of all males, and then put them outside at that time.