Aggghh, plant proposal needed for my croton.? My croton house plant is looking not so good. I marine it...

My croton house plant is looking not so good. I marine it with Miracle Grow nutrient around ever 2 weeks. It is in a big pot. It used to look adjectives leafy but now it is looking a sadder edition of it's former self. It is losing leaves even green looking leaves not just limp ones. Is this just seasonal? It looked fine this summer.
I save it by a west facing window sill it have been here for about 18 months or more.
What is going on?
Recommend streets to live implicit Chiswick?
Answers:    My warning is that:

either of the results own happened

1. over watered and feed too much
2. two dry , feed have killed the roots of the plant/
2,5 you hold water the plant through the top of the plant i.e the nurture / water have touched the leaves
3. the plant is in a draughty place/ probably too cold of a room
My garden is mortal accost by Japanese beetle....
Your giving it to much water,and method to much fertiliser.They like to be kept moist,but not showery. They need allot of humidity,and at least possible 4 hrs. of sun each hours of daylight. Feed every other month from early spring thru mid- summer. Don't nurture them after that. I have mine outside right in a minute and it's doubled in stage. Also look around the stem where the leafs start to grow,for Mealy Bugs. Those are whitish cottony looking things . If you hold them ,use a cotton swab and rubbing Alcohol to wipe them off. Byee