is my substrate good enough?

[caffeine]

I'm setting up my first planted tank. At first I was just going to use rock and sand as the substrate, but then I realized it might be a good idea to do some research before I fill it up and start planting. My plan is:

bottom layer: mostly sand, some rock, and sphagnum peat
top layer: regular aquarium gravel

Good idea or bad? Do I need to add some soil to this or will the peat do for organic material? What percentage of my substrate should be peat?

I already have all of these materials, and the sand is already in the tank and isn't coming out easily. If I'm doomed, please let me know, but is this good enough for things to grow?

Tank is 20L with 40W of lighting.

[Robert H]

Peat has some benefit, but should only be used in very small amounts. A large amount of decaying peat in the substrate can cause severe problems. Using some kind of clay gravel or additive is much safer and will provide iron and minerals for the plants.

[NJ Devils Fan]

I would add flourite as the bottom layer and then sand of any kind on top.

[djlen]

Agree with Robert and Devil Guy. Flourite and sand is the better option. Especially later when you decide to move plants around.
Uprooting out of peat is messy and can cause other issues as well. That stuff is not going to stay perfectly layered as it will be when you first put it in.
Len

[125gJoe]

SeaChem's Onyx Sand (http://www.aquariumhobbyist.com/discus/amano/)
Scroll down a bit and you will see 'Mr. Amano' using Onyx Sand....

I'd go with that at 100% Onyx, or 100% Flourite. No need to mix anything in there for great substrate! :cool:

[caffeine]

I got a bag of fluorite today. I would love to use nothing but this stuff for my substrate, but I really don't have that kind of money to spend right now. I would probably need 3 bags and this one cost me $18.50 at the LFS.

I'm going to mix up this fluorite with some sand to make the bottom layer about 2" deep and then put a layer of regular gravel on top.