swell gel and plant food

I always pre-swelll water retaining granules for summer containers, as I find it stops the compost overflowering when I first water. I was wondering if it was a good idea to use diluted plant food instead of plain water to fill them. Whaddya reckon? Presumably the water in swell-gel is availabe for the plants to actually use, and so the fertiliser would be too.. Just a thought. I don't like using feed granules as I'm never convinced they stay wet enough to actually disperse the food - they're always still there at the end of the season.  Does anyone else do this? Bx