First off where is this dust coming from? If it's coming in from outside that box you might try to find a good air filter for your inlet.

As for what it tastes like when ready to smoke, Look into curing and drying. Curing gets rid of the chlorophyl which gives it that grassy taste, But you have to do it right.

http://boards.cannabis.com/grow-faqs...your-buds.html


As for topping plants, From what I understand. If the plant is reaching for the light. Move the light to the plant or get more light.

A plant CAN be topped and after some time will produce more branches to grow taller again. I see no reason you can't do this. However if your plants are reaching for light topping may not be the right thing to do. There are many people here who condone training your plant to one side (slowly train it to lay down) then moving the light closer. Again the plant will produce more branches without that healing time caused by topping.