Start by using a fert with a lower NPK. Avoid the higher numbers like 24 -8- 16. You plants will not use it. Instead of mixing per instructions - full strength, mix a batch at 1/2 to 1/4 strength. And feed weak solution more often. Better for the plants. Also look for an organic fertilizer, this may help with leaf burn.
I also use a time release fertilizer like osmiocte and sprinkle a handful in pot. This will be good for the entire season.

Here is a link that might be useful: My Blog

Have you ever looked into actively aerated compost tea? It's organic and works great if done properly. You can't over use the stuff and it actually helps if you get the tea on the leaves.

Actually, 24-8-16 is an excellent fertilizer choice for an extremely high % of all containerized plants. It supplies nutrients in almost exactly the same ratio as that actually USED by plants, which allows you to fertilize at lower rates (EC/TDS) than fertilizers like 1:1:1 ratios and high-P products and still avoid deficiencies and excesses (toxicity). In fact, it would be very difficult to make a case for fertilizers other than 24-8-16 and the rest of the assortment of 3:1:2 ratio fertilizers as not being the most logical choice as your 'go to; general purpose fertilizer. I use Foliage-Pro 9-3-6 (another 3:1:3 ratio fertilizer) on all my containerized material.

If you're still interested, Barb, you might find the accompanying link of interest.

Al

Here is a link that might be useful: More about fertilizing plants in containers here