Hi i use Osmocote Plus on everything i grow and it works great and its slow release to last up to 6 months before you have to add more and i also use

Miracle-Gro Water Soluble All Purpose Plant Food once a month as a boost to the plants

http://www.plantersplace.com/products/osmocote_outdoor_indoor

Thank you!

If you want a fertilizer for free....clover. Most people rip it out because it's a weed but it pumps nitrogen into the soil, which is usually what most tropical plants lack. There are some nice ornamental ones. If you plan ahead...peas or beans. Chemicals will only work for 6 months or so.....