What type of plants do you have? And what sort of lighting do you have?

I have 2 pinwheel sword plants, 1 Italian vallisneria, 1 bunch of false loosestrife and I have white LEDs in my tank.

If it's the typical LEDs that come with the fishtank, it's not providing enough light or the right spectrum. Usually for planted tanks youre supposed to have 2 watts per gallon, but for low light plants you can go as low as 0.5 watts per gallon or 1 watt per gallon. That's why many people with planted tanks either use fluorescent bulbs, T5O's, T5HO's, or make they're own LED lighting system. You can also purchase high power LEDs and ones designed specifically for aquatic plants but they get pricey.

You're plants are generally low light and easy, but you need to increase the wattage of light in your tank.

I had a 20 gal planted tank and just used gravel as a bottom and I used a T8 15 watt bulb designed for planted aquariums. I was able to grow anubias, amazon sword, cryptocoryne, java moss, red ludwigia, and vallisneria without any issues. I only fertilized the weekly dosage of flourish aswell.

Now I have a different tank with different wattage and liquid Co2 and stuff and it grows alot faster, but isn't necessary unless you have high light level plants.

So in summary, plants need a proper combination of the right light levels, medium, and ferts to grow. Just fertilizing won't do much if the plant can't utilize them.

There are some good aquatic plant related forums around the net and you'll get a load more answers and proper info if you post there. A good one is aquatic plant central.

Good luck!