My substrates are rather complex and can go badly wrong if you don't know what you're doing, but you can certainly use just a planted substrate like Eco-Complete. Its a dark and rather sandy, and will make your fish colors really pop. They and the other major planted tank substrate Flourite contain chelated iron, potassium and other minerals necessary for plant growth.
If you wish, I can email you four text files I've written on four groups of plants: swords, bulb, stem and Cryptocorynes. They will tell you all you need to know about substrates, lights and Co2. I also have an expansive book list. PM me if you want any of them.