you need a Pokemon that knows secret power use that move to make your secret base
on sapphire/emerald this one boy gives you the move secret power. use it to make a secret base!
Unfortunately there is no TV in Ruby/Sapphire/Emerald for a secret base. Many people worldwide will be upset. :(
Stand at the front of the clump of grass and press A but you must have a Pokemon with you that knows the move secret power and it should ask you if you want to create a secret base there. Hope it helps :)
fly to the pokemon center and take a left, you will see a house. go in the house and talk to the kid. he will tell you what route your base is on.
after catching latias/latios YOU DO NOT HAVE TO CATCH LATIAS/LATIOS TO MAKE A HUT!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Use secret power on certain trees, bushes, or those black squares in the sides of mountains
If you have or have taught a pokemon the move Secret Power, you can use it on those vine trees, notches in cave walls, and big bushes to turn them into a secret base.
in lilycove city in the giant store on the floor before the top floor
you don't. you use it in Pokemon sapphire to make your secret base.
well they are secret bases but you need to teach one of ur Pokemon secret power(tm43), and u can get it in slateport city at the open market!(In Pokemon Sapphire).
well im sorry to say but NO. you can only do it in Pokemon emereald, Pokemon sapphire and Pokemon ruby. and once again u cant do it in Pokemon soul silver or Pokemon heart gold
i think you use the TM secret power but im not sure so try it and see if it works