Reposting my pattern for Gramma Cookie's granny square.
Gramma Cookie's Solid Granny Square pattern was on the Knit A Square forums pages, but isn't there any longer, so I'm replicating it here on my blog.
It can be crocheted either half double crochet/double crochet, or double crochet/treble crochet.
This pattern is in U.S. terms.
Hook size: U.S. size H
Yarn weight: Worsted or Aran, approx. 60 yards.
Round 1: In a Magic ring, sc 1, then ch 5,
(3 dc in ring, chain 2), repeat two more times,
2 dc in ring, sl st into the 3rd st of beg ch 5 to make the third dc of the last cluster and close the first round.
Pull starting yarn tight to close the magic ring, and crochet over it as you continue to build your square. (12 sts, 4 ch 2 spaces)
Round 2: 1 Sl st into the corner space. This helps make room for the last st of the ending cluster later. Ch 5, 2 dc in same ch 2 space, *dc in each dc on the first side, (2 dc, ch 2, 2 dc) in corner ch 2 space.* Repeat for the next two sides.
Dc in each dc on the last side.
In last corner, 1 dc over the starting sl st, then to finish the corner, sl st into the 3rd st of beg ch 5 to make the second dc in the ch 2 space and close the first round. (28 sts, 4 ch 2 spaces)
Round 3: Repeat round 2 (44 sts, 4 ch 2 spaces)
Round 4: Repeat round 2 (60 sts, 4 ch 2 spaces)
Round 5: Repeat round 2 (76 sts, 4 ch 2 spaces)
Round 6: Repeat round 2 (92 sts, 4 ch 2 spaces)
Round 7: Repeat round 2 (108 sts, 4 ch 2 spaces)
If I'm using Red Heart Super Saver yarn, seven rounds makes an 8" square, which is the required size for Knit A Square.
If I'm using thinner yarn such as Hobby Lobby's I Love This Yarn!, I may need to work an eighth round in single stitch, to reach the 8" square size.