My initial experience was mid-summer last year, and I thought it was good for my veggies. In general, I've been disappointed with my veggie yields, the foliage production seems to outstrip the edible fruit production.

You imply using guano on vegetable plants in late July/early August (mid-summer). Vegetable plants should be blooming and setting/forming edible portions by then and lots more fertilizer could promote foliage growth at the expense of the edibles.

If the plants were already growing well by mid-July, even watering is more important. If they seemed slow to grow, a little more fertilizer, regardless of type, can help.

Guano is a component of some common, bagged fertilizers.

What is an example of your vegetables that were mostly foliage?

Since most organic fertilizers take time to breakdown and the nutrients become available to the plants, applying it early in the season is better than later. Applied in moderation/package instructions, it is pretty darn hard to "over do" with organic fertilizers. And guano - as are a lot of organics - is not exactly cheap. 1-2# for 100 sq. ft is all that is necessary.

Before taking the time and expense to add fertilizers, perhaps unnecessarily, you might want to consider having a soil test done. That will tell you if you have any deficiences and how to correct or if you should be looking at something else altogther.

If you are trying bell peppers, those require an excellent, rich soil and even watering and perfect weather conditions to get store-sized fruits. I see very few casual gardens here that generate full-size peppers. Bell peppers set fruit in a fairly narrow range of temperatures and some years here just don't cut it at bloom time.

It is actually easier to grow hot peppers, and that includes many hybrids that have the appearance of a jalapeno but have been bred to be very mild. Pimento-type peppers can also do well in the same conditions bell peppers struggle in.

The vegetable forum likely has more frequent advice.