My plant is almost 3 weeks into flowering. I am slightly concerned because the top part of the plant seems to be flowering at a much more rapid rate than the lower section of the plant. Its quite a large plant, about 4 foot high (not very busy though). Is this normal? How will i know when to harvest or will i need to gradually harvest as each set of buds ripen?
Your tops are probably budding better than you lower level because most likely the light is reching the top better than the bottom. What you can do is get maybe 3 or 2 CFLs near the bottom area. The best way to know when it's harvest time is when you see brown, reddish hairs that used to be white or a yellow tint. If you want to harvest the most potent bud wait until you have white powderish like material on your leaves and buds or get a microscope and see if you have crystals.
Yes this is normal. Light has alot to do with it, but in some cases its simply not possible to get light to every area of the plant you want too. This is why i use the technique that was taught to me years ago, and thats snipping the very top of the top bud off. What this does is stops the vertical growth of that top bud and all lower buds will be forced to bud bigger/faster and more dense.
So i just snip the very top bud off? Is this different to topping in the sense that i dont cut at the stem, i cut right across the bud, or just at the stalk where the bud starts?
I think he means the tip of the top bud, not the entire top. But im not sure, i have never heard of this but its very interesting.
If I understand Dierwolf correctly, you dont cut off the bud. Just the tip of the main cola. Wich would be maybe 1/8th of a gram, not much of a loss considering it will fatten up everything else.