Low light plants?

[B-Chrono]

So I got a 20 gallon high tank for free on craigslist and want to plant it with some plants that don't need a lot of light. I'm new to the whole plant thing but the light it came with is a 9.8 watt led fixture, I know the wattage is pretty low. Is there anything that will work with this and a pool filter sand substrate?

 

[agrasyuk]

anubias always works, one of my favorite plants by far.
amazon swords will do fine in sand if you add some root tabs once in a while. java fern and various mosses also come to mind

 

[B-Chrono]

I guess my main lack of knowledge is lighting, general rule of thumb is 1.5-3 watts per gallon correct?

 

[agrasyuk]

my general rule of thumb - the stock CFL bulb would be on lowish side. which still grows low light plants well, the exact math doesn't bother me to much.
to go to medium and up you will need T5HO or higher end LED fixtures.

 

[Alan79]

The wattage of the leds is less important than the light color of them. For plants they should all be above 6500K in light color to give energy to plants. Any light that is below the 6500K color range will cause algae to grow quicker than the plants.

Anyway some nice low light plants
Stems
Ludwigia repens (many Ludwigia varieties do well in low light)
Sunset hygro
Pennywort
Water sprite

Rosette plants
Anubias (every variety is a low light specialist)
Crypts. I have 4 varieties that have done really well in low light when they're listed as medium light plants.
Dwarf chain sword

Many mosses will also grow in low light but Java moss in particular does really well in low light for me.