Green Thumbs, Please Advise

Back in the spring when I visited the Flower Market in Mong Kok, I bought some herb seedlings. I placed them on the balcony and soon began to enjoy things like fresh basil in my tomato sauce and classic cocktails like mojitos and mint juleps.

Lately, however, it's become clear that something has gone very wrong. Is this not the saddest excuse for a garden you've ever seen?

The basil plants in the back row (Thai on the left and Italian on the right) are technically alive, at least, but the leaves are very small and tough. The stems and leaves of the mint plant (middle left) are oddly shriveled. The lavender (middle right) was doing quite well for a long time, even though it refused to flower. But now it too is going into a definite decline.

The small pot in the front used to look like this, at the New Year:

I tried adjusting the amounts of water and sunlight, but nothing seemed to work. Am I simply in the wrong climate to grow these kinds of plants? Do I need to get some kind of special fertilizer? Hoping there's a green thumb out there who can give me some advice so that next season's garden will be something I'll be proud to display on this blog.