I didn't write this but it might be true lol, One day you will notice that your plants appear to be doing more than just growing vertically and producing leaves. You take a closer look and there appears to be new leaf growth at most of the node regions between the stem and the branches. Your plant is now developed enough to receive more light energy and covert this energy into more side branch growth. These new growths produce more leaves, branches, and eventually flowers. This type of new growth at the stem's node regions is called lateral branching or secondary branching. This is really where the extra node regions begin to take shape.
After a few more weeks of this secondary growth your plant is looking more bushy and certainly has more node regions. It is during this time that your plant has reached sexual maturity and is ready to show sex. How long this takes depends on the strain you are growing but after the seedling stage has finished you are looking at a time period of 4 to 8 weeks vegetative growth. With Sativa strains this can take much longer.