For the last couple of years, I've been nursing along a sort of kitchen window herb garden consisting of cilantro, parsley, basil and chives. What I've done is bought live herb plants at our local grocery store and re-potted them in individual pots to make it easier to move around and so on. The window is west-facing and gets very good light in the afternoon and our kitchen is obviously warm and relatively humid. It seemed to me an ideal location for herbs, but except for the chives have not really prospered.
But recently, aphids attacked my basil, which I moved to the front porch on the east side of the house. After that, the aphids attacked the parsley and the cilantro, which tells me that: a) the source of the aphids is somewhere close to the kitchen window, and b) aphids prefer basil over cilantro and parsley. The chives are growing like champions and seem to resist the aphid onslaught.
More importantly, the herbs I moved outside look better and healthier than they have in months. In particular, the basil has suddenly burst forth in leaf and I could imagine myself harvesting some without stripping it bare. It's a bit of a mystery to me.
Given that I'd rather have herbs growing in the kitchen where they might get used than on the porch, what could I do to improve the growing conditions inside?
Update: Based on winwead's answer, I observed the approximate time that direct sun ended in the kitchen and yesterday it was sometime before 6pm. Since full sun could not start before 1pm, that window has less than 5 hours of direct sun. (It's counter-intuitive since the kitchen seems so bright all day long. Most of that light, however, is indirect and reflected from the light stucco on the building across the alley.) Sun starts on the porch around 8am and gets good direct light until at least 1pm, if not longer. So that's a solid 5+ hours.
The lesson for me: it's better to measure than to guess. Also, I need to search for herbs and plants that thrive in less direct sun for my kitchen window.