Perfectly Flat HDC Circle
The trick to crocheting a perfectly flat circle is to begin with the correct number of stitches and to increase each round by the same number of stitches in the first round. For the Half Double Crochet (HDC) stitch, we begin with 10 HDC in the beginning center circle. Then we increase by 10 stitches each round. This means to add 10 stitches in each round, which will be two stitches together, evenly spaced around the circle. If you increase too few, your circle will start to curl in like a bowl shape. If you increase too many, your circle will be wavy and won't lay flat.
I have a video below to show you step by step how to do this. I used worsted weight yarn with a H8/5mm crochet hook. These instructions will work for any size or type of yarn, use the manufacturer's recommended hook size.
ABBREVIATIONS CH = Chain HDC = Half Double Crochet SL ST = Slip Stitch
RND1: Begin with a magic circle (or your favorite beginning circle technique). CH 1. HDC 10 in center of circle. Join with a SL ST in top of 1st HDC.
RND2: CH 1. HDC 2 in same stitch and each stitch around. Join with SL ST in top of 1st HDC. (count=20)
RND3: CH 1. HDC in same stitch. HDC 2 in next stitch. Repeat this pattern of [HDC, HDC 2] all the way around (9 more times). Join with SL ST in top of 1st HDC. (count=30)
RND4: CH 1. HDC in same stitch and next stitch. HDC 2 in next stitch. Repeat this pattern of [HDC, HDC, HDC 2] all the way around (9 more times). Join with SL ST in top of 1st HDC. (count=40)
RND5: CH 1. HDC in same stitch and next two stitches. HDC 2 in next stitch. Repeat this pattern of [HDC, HDC, HDC, HDC 2] all the way around (9 more times). Join with SL ST in top of 1st HDC. (count=50)
Have you noticed the pattern yet? There are 10 increases (HDC-2) every round. Each round we add an additional HDC between the increases. Continue this pattern until the circle is as big as you'd like.
Happy Crocheting!
-Amanda