Posted: 23/07/2016 at 17:38
More important to feed after the flowers go over and the plant's dying back, as that will give it a boost. As long as you leave the foliage on as well, that feeds the bulbs for next year.
Excess food can often just be a waste. Good drainage and a bit of sun is about all they need to do well
It's all a learning curve
You may also find they'll outgrow the pot quite quickly as they do become big plants, especially the ones you have. My lilies are about to go in the ground now that I have a space for them. They've been in the same (18") pot for a couple of years, but they're nearly twice the size this year, which is also normal as they gradually mature.