get dog to pee outside on small grass area

Question
How do I teach a 5 year old dog (rescue dog) to go (pee and poop) on the small grass area in the courtyard.  She goes on the grass in the park when I take her walking (she will not go on cement). I bought a couple of grass patches and put in the courtyard--they are growing.  I have a doggy door which she uses to go out into the courtyard but she will not use the grass.  i have caught her pee and poop while walking and smeared it on the grass-nothing.  I have taken her out to the small grass plot in the courtyard when I know she has to go--nothing.
Help

Answer
HI Ann:

I would think two patches of grass is not enough, as dogs like to sniff around before going.  (However you do not mention the size of your dog, if it's a pocket sized breed two patches should be enough).

There are several products on the market called Puppy Training Aid's these may work.

The other alternative is to crate train and when out for pee break, have on leash and keep on grass.