I think this decision should come out of your own experimentation based on your environmental conditions - the amount of sun, temperature, the container mix, how much you water, what the composition and type of the fertilizer is, and most importantly, the plant and its age, etc. Sometimes you can find 6-packs or other potted annuals (or tender perennials) that already have a slow-release fertilizer in them like osmocote (the little yellow balls on top of the soil). When I see something like that, I'll wait before initiating any additional fertilization. I have even gotten into the habit of using slow-release myself so I may add some on top of the soil and just water for the next couple months.

I think the fact that you researched it is good and perhaps you should just follow the label directions from what you bought or maybe go a little dilute at first - just to see how your plants respond, and then go from there. Once you find a successful scheme based on your own cultural practices, you'll be one of the ones adding to the threads about what you found worked best for you! :-D

I used to mix osmocote in my potting soil, and call it a day. However, afetr talking with several of the annual suppliers locally, I'm following their lead. They also mix in a time release fertilizer at planting time, but then EVERY time they water, they use a 1/4 strenght miracle grow type product. It keeps the annuals producing big flowers all season--it really makes a difference. My only caution would be to reduce that to every other watering when the temps are over 90- just to be careful not to burn the roots. Robin

There as many techniques for fertilizing plants as there are gardeners ;-)

You are realizing that by reading the info provided by various 'expert' sources as well as various opinions.

More or less they are all correct ;-)

If anything I would err on the side of underfertilizing so ferting with every watering is not something I would do unless the plants were very lackluster in their performance in comparison to what I thought they should be doing.

For example, a heavy blooming annual may slow down it's blooming. Give it a feeding and a week later it is in full bloom again. Experiences like this, over time, will give you a sense of what, how much and how often more so than any routine, one size fits all schedule will.

I think a good 'starting plan' is to mix in a little slow release fertilzer (get one that is labelled as a "complete" food meaning it has micronutrients in it instead of just N-P-K) and then use a fert mixed with water every couple weeks at half strength. From here, alter the frequency and strength and wait a couple weeks to observe how the plants respond.

It's a bit more complicated in that some plants need really high fertility and others very little so knowing a bit about the plants you are growing (you can just divide them into low, normal and high) for their fert needs helps. But, this comes with time as well.

No worries, err on the side of caution with ferts and everything will work out fine. Waaay easier to cause problems with over ferting than under ferting.

I use Miracle Gro. The directions say every 7 to 14 days. I try to use it every 14 days but sometimes I don't get around to it that often. I find when I DO it consistently, I get great results for both leaves and flowers.

Do check your potting soil labels. I buy Miracle Gro soil because I like the consistent texture (I mix in some perlite for plants that like extra drainage like tropical hibiscus). It used to have 30 days worth of fertilizer in it. The soil I bought this year now has 90 days worth. So I shouldn't fertilize for three months.

About your question about keeping annuals dry when watering, that is to avoid fungus diseases from foliage being wet at night or fertilizer burn if you have fertilizer water on the leaves in the hot sun. For the most part I disregard that advice. I did notice a bit of spotting on the leaves of a few varieties last time though.

Plants that are heavy feeders take up the food quickly through the leaves, so that's why I like to water the leaves too.