The time needed for a graft to take depends on the species, but a general rule of thumb I use is about the same time it takes for cuttings to strike. For herbaceous plants, six weeks. For semihardwood, six to eight weeks. Semi hard to hard wood is about 8 to 10 weeks.

The simplest way to find out is have a look at the graft union. Does it look like it has calloused over? Is there new growth on the scion (the desired grafted plant)? By the sounds of it, you should be okay to remove grafting tape/clips at the moment. It should be readily aparent if the graft has been successful, i.e. the root stock and the scion look like they have grown together successfully.

Be sure to harden off the the plants in a semi-shaded position for a few weeks before moving them into full sun. This ensures any extra lignification between the rootstock and the scion that may be required should be sufficient before planting the species out.

Good luck.