YourGardenShow.com "Ask Ian"
Video reply: Plants grow to perpetuate the species. Its goal is either to make a flower and set a seed, and have that seed ripen, or put out runners and creep along the ground, or in some way reproduce.
Typically the flower is the method. Once a flower sets seed, it no longer has to put out new leaves; and with herbs, particularly basil, the leaves are what you want. Note that all plants are different, and with every situation - nutrient, water and temperature, you will get different responses.
But as a rule, with basil, yes: pinch off the flowers, and sometimes even pinch the plant back. It's beneficial to avoid mass planting of any one crop - that way if one area of your crop gets knocked down from a bug or other issue, you'll still have other places where that crop is thriving. I usually intersperse my rows of basil with other types of plants so that I can come in and cut back those plants quite hard; then, while those plants rejuvenate and regenerate, my basil in other areas are growing nice foliage.
Sometimes you have to pinch the plant down very low. Basil can grow quite high and you may want to consider chopping it down to half, and letting the plant completely rejuvenate and you'll get a lot more good foliage from it.
Added benefit: Basil is aromatic, and there is a certain thinking, that basil, along with marigolds, can keep away some of the bugs that we don't want in our garden. This video reply was first broadcast online during our live plant and gardening Q&A show; the video you see here has been edited from a recording of that show. Got another question? Go to the Q&A page