Last summer I learned a technique from Charlene Schurch that will help you to avoid that gap at the top of your gusset forever! I will explain this tried and true technique in a moment but if you want an excellent explanation with pictures, please take a look at Sensational Socks by Charlene Schurch. I have used this book to teach several friends how to knit socks. It is one of my favorite knitting resources.
Let’s pick up those stitches for our heel gusset………….
We are going to drop down to 4 needles for the gusset. Our stitches will be on 3 needles and the 1 empty needle will be our working needle.
Using the empty needle, pick up 18 sts along the right side of the heel flap. The grey slipped st will be the last st you pick up. Now 2 additional sts will be picked up at the top of the gusset. To do this you need to look for the horizontal bar between the first instep stitch and the heel-flap stitch. Those little sts that loop over on either side of the bar will be the sts we pick up. Using gusset needle insert the needle into the loop on the heel flap side and pick up 1 st. Pick up the right half (instep side) and put that loop on the gusset needle. Now you have 20 sts.
Needle 1: Knit all the instep sts onto a single needle following the K3, p1 pattern. 35 sts.
Needle 2: With empty needle, pick up 2 sts at the top of the gusset on either side of that horizontal bar. Then, pick up and knit 18 sts along the left side of the heel flap. 20 sts.
With Needle #2 continue to knit 9 sts from heel flap for a total of 29 sts on Needle#2.
Needle 3: With empty needle knit 10 remaining heel sts. Then, knit the 20 sts picked up from the right side of the heel flap.
Your needles should now have the following stitch counts:
Needle 1: 35 sts
Needle 2: 29 sts
Needle 3: 30 sts
Total on all 3 needles: 94 sts.