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.

Hi, when you water try to figure it as one inch of rain. That's a lot of water so let 'em have it at least once a week. Fertilizer should be applied when it becomes apparent. Too much will bring on the pests. Read the directions on the container/package. Slow release type is the easiest since you only apply it one or two times. By all means mulch heavily around the plants to conserve water. Best of luck and have fun.

I probably exaggerated some-- for example, there's a bit of potassium on the loose in every cell-- but it's basically true. People think of roots as being stuffed with phosphorus, but P doesn't have anything particular to do with root or flower development. P is needed all over the plant in small quantities as part of the information systems and energy-transfer systems, in order for the plant to get anything done. What's stored in roots is not P but sugar and starch. P is prescribed for root vegetables because these plants have small root systems and may have trouble foraging for P in the soil. Extra P is needed only for ripening seed, and we don't have much of that in the rose garden. Actually phosphate is the classic placebo fertilizer because you can use a lot of it without doing any obvious damage.

Flyingfish2: I know some people prepare weak fertilizer solution and use it every week. I want to use only organic and prefer using dry fertilizers. One time I used seaweed solution on newly planted tomatoes and it really made them growing fast comparing with others. Lukas nursery used to have ready seaweed fertilizer, but I don't see it there now.