Pyramid,
First off all - 3Gallon and as long it's not by a door or window and it doesn't get cold in your house your 3G tank will be fine without a heater, saying that I would atleast like someone said stick a Temp sticker on the outside - Digital temp isn't really needed you would end up spending more on the temp then the tank itself.
Sponge filter should be fine
Lighting you can pick up any clamp on reading light and depending on the bulb size it should do the trick fine, if it doesn't go try something else. I've found that the best thing about the fish hobby is expirementing on what works and what you like. Someone could tell you to go buy this light or this plant and they might not work with your setup. Suggestions are great but shouldn't be taken to heart and you shouldn't be 100% set on peoples opinions because like I said it might work for that person but not you. Also lighting depends on what kinda of plants you want to grow I've grown "High Light Plants" in under 1 WPG and they've done fine.
Substrate - I'm a firm believer that you don't need expensive Florite or Eco-Complete to have plants or a planted tank. I've used Home Depot Playsand in all my aquariums and have sucessfully grown alot of plants. All plants will taken Nuts from the WC (water column) Root feeders like Swords, Lotus, Vals will be better off with getting there nuts from the substrate because they are all heavy root feeders but will still be fine without them. If you are worried use a 50 cent root tab and place it in the substrate which usually last 4-6 months.
Also the only way to learn is to make mistakes, mistakes are the best to learn from because you sure as hell don't want to make the same mistake again.
First off all - 3Gallon and as long it's not by a door or window and it doesn't get cold in your house your 3G tank will be fine without a heater, saying that I would atleast like someone said stick a Temp sticker on the outside - Digital temp isn't really needed you would end up spending more on the temp then the tank itself.
Sponge filter should be fine
Lighting you can pick up any clamp on reading light and depending on the bulb size it should do the trick fine, if it doesn't go try something else. I've found that the best thing about the fish hobby is expirementing on what works and what you like. Someone could tell you to go buy this light or this plant and they might not work with your setup. Suggestions are great but shouldn't be taken to heart and you shouldn't be 100% set on peoples opinions because like I said it might work for that person but not you. Also lighting depends on what kinda of plants you want to grow I've grown "High Light Plants" in under 1 WPG and they've done fine.
Substrate - I'm a firm believer that you don't need expensive Florite or Eco-Complete to have plants or a planted tank. I've used Home Depot Playsand in all my aquariums and have sucessfully grown alot of plants. All plants will taken Nuts from the WC (water column) Root feeders like Swords, Lotus, Vals will be better off with getting there nuts from the substrate because they are all heavy root feeders but will still be fine without them. If you are worried use a 50 cent root tab and place it in the substrate which usually last 4-6 months.
Also the only way to learn is to make mistakes, mistakes are the best to learn from because you sure as hell don't want to make the same mistake again.
As long as you have some light going in there your plants will stay alive. I would tell you to just expirement with different lights just to see what works. If your only you going to plant a crypt make sure you don't plant it's rhizome. Most people when they plant crypts will attach them to a rock or driftwood. The crypts will get there Nutrients from the WC and are heavy root feeders. Be careful dosing excel as this can cause melting if not properly added and dosed.
