I used sta-green garden soil plus fertilizer for flowers and vegetables to fill my raised veggie garden bed. On the bag, it says "feeds plants for up to 9 months." I planted my plants one month ago, and I'm wondering if it would be good, neutral, or harmful to use a fertilizer. In the garden I have flowering and fruiting bell peppers, mature and sprouting swiss chard, kale, collard greens, cabbage, flowering cucumbers, sunflowers, mint, carrots, basil, golden onions, parsley, and broccoli.

Many gardening books/websites I've read talk about the importance of using a good fertilizer, and I've also read a little about how over-fertilizing can "burn" the plants. So should I fertilize, or will the built-in soil fertilizer be sufficient?