There are 5 columns and 8 rows.
Materials: At least 1.25 yds of cotton poplin or flannel. You need extra to account for shrinkage and straightening the ends. Wash and dry at least twice on hot before cutting it.
5lbs of craft pellets for each blanket. craftpellets.com
1. For each blanket cut 2 pieces 21" x 31.5" from printed cotton. Jakob picked out this glow in the dark astronaut print from fabric.com. Unfortunately the cotton flannel he chose shrank quite a bit in width as well as length. I ended up using the fold of cloth as one side of the blanket instead of being able to seam it, which was fine.
2. Using 1/2" seams sew the sides and bottom. Either use a serger or sew a second row of stitches a quarter inch from the first stitching line towards the outside edge. Fold down 1/2" and press across the open top edge of the blanket. Press the seams. Turn right side out.
3. Sew 5 columns 4" wide the length of the blanket.
4. Measure and mark the lines for the horizontal boxes that will hold the craft pellets. I found that the chalk marks rubbed off before I got very far up the blanket. I marked all of the lines with blue masking tape on the upper side of the line before I started sewing.
5. You'll need a scale to divide up the pellets. 5lbs or 80 ounces divided by 40 boxes comes to 2 ounces per box. I used paper cups to fill each row. Pin at least 1/2" below the line so that your presser foot won't get caught in the pellets. I found that I had to take small bites in the fabric with my pins overlapping the ends so that the pellets wouldn't migrate into the sewing line. You definitely can't sew over these little pellets! When I got towards the top I pinned each box after I filled it. They are too easy to spill out otherwise! Here's the finished blanket.
Jakob with the finished blanket. He likes it, but he loves that the astronauts glow in the dark.
If you have any questions please feel free to email me.