Not sure in what light
fishluver93 asked her question but I'll assume she is inferring that plants aren't a cure for Algae but instead can help inhibit it's growth since they compete for the same nutrients.
But heck even in my planted tank I have Algae... yuck!
Truly getting rid of it - without chemicals - is a multi-plan of attack.
1) Frequent water changes
2) Controlled feedings (some fish food encourage algea growth!)
3) Lights on reasonbly (not 24-7) and the correct lighting (one encourage Algae growth)
4) Regular Tank cleanings (suck'n up the muck that eventually turns into Algae food!)
5) Algae Eaters
6) To a lesser extent, regularily cleaning your filitration system
7) Plants! (and cO2)
Plants aren't TOO demanding to grow they do add another dynamic to the tank
1) Need for fertilizers
2) Need for a plant-friendly substrate
3) Proper lighting (linked to item 3 above)
4) Possibly adding cO2 to the tank.
5) Friendly water (I think - but not too sure - plants prefer neutral to soft water -fish nerds please correct me!)
Another thing I have going for me (when things DO go right for me) is a canister I use that has a microbial filter - I can scrap the walls and with the canister running, it polishes the water and actually pulls the Algae out. But like I said, I still have Algae... So to an extent it's also dependant on how pro-active I am... Like it's hard to not overfeed the fishies... I got a soft soft them buggers and hate to think they're starving!
Getting back to your question.. I don't believe there is really an answer here... I might even go as far as suggesting WITHOUT doing the stuff above to just keep adding plants until you notice an impact on Algae (meaning the plants are consuming what WOULD have gone to Algae).
After all, since you have Algae, the conditions are right to grow at least 'some' plant life - whether it's enough to support higher forms of plant life are up for grabs
