What do i need for live plants in my tropical fish tank?

You do usually need some light, but there are plenty of low-light plants, and most people agree that plants will grow more slowly, not die, unless they're absolutely deprived of all light. It sounds to me like you need a basic review of plant nutrients and nutrient cycles in the tank; if you don't have the proper set of supplements like CO2 or iron for example (there are many others), your plants will quickly die regardless of what light, water temperature, and pH conditions you're attempting to grow in. You may also want to check gH and kH; this matters more for some plants than others because of how ions influence basic metabolic processes. This is a good link that helped me get started when I was setting up my first tank: http://www.americanaquariumproducts.com/AquariumPl...

Do more research into the differences between plants; if you don't want to invest in a lot of lighting or nutrients, go with the ones that are hard to kill like Java Moss, Java Ferns, Elodea (sold as Anacharis), Anubias, etc. These will also tend to grow in low-light, albeit a lot more slowly. You can also grow Duckweed which grows really easily, but it basically blocks out light for everything else. I don't think substrate is necessary, but using certain ones can help your plants grow better, and many will grow more quickly if they're rooted in something. You can still leave them in the pots or anchor them with weights if you plant them.

You need 6500k blue light. Plants won't grow without light.

low light/ low tech plants need 1-2 watts per gallon so in 60 gallon you would want 60-120 wat bulbs minimum.