Here is the how to make plarn tutorial link that shows detailed pictures on how I create plastic yarn from recycled plastic bags.

Click photos to supersize closeups

Free Plarn Backpack Crochet Pattern

Materials needed:
One very large ball of plastic bag yarn “Plarn” – Approx. 60-70 plastic grocery bags
1 oz. of scrap cotton yarn
1 buckle hardware latch for front flap

Hooks:
“N” U.S. size metal hook for main body of backpack
“J”, “H” &“G” U.S. size crochet hooks for straps, trim, and drawstring

Description: Plastic Bag Plarn Backpack or Knapsack
Bag measures 13” wide and 13” long with 18-1/2” back straps

Directions:
Ch 18

Rnd 1
Hdc in 2nd ch from hook and in ea chain st down to end. Work 2 Hdc in end st, then continue around other side of chain by working a Hdc in ea st to other end then work 2 Hdc in end st.

Rnd 2
Hdc in each st around to first end, work 2 Hdc in ea of the two end sts, then Hdc in ea st to other end, then work 2 Hdc in ea of the two end sts. Do not connect at end of rounds, just continue working Hdc’s in rounds as this creates a seamless bag.

Rnd 3
Hdc in each st around to first end, work 2 Hdc in ea of the 3 end sts, then Hdc in ea st to other end, then work 2 Hdc in ea of the 3 end sts.

Rnd 4-5
Hdc in each st around to first end, work 2 Hdc in ea of the 4 end sts, then Hdc in ea st to other end, then work 2 Hdc in ea of the 4 end sts.

Rnd 6
Hdc in ea st around the entire bag bottom.

Rnd 7
Working back loops only, Hdc in ea st around. This creates a flat, expandable bottom to your bag.

Rnd 8-9
Working in both loops now and throughout the rest of the bag, Hdc in ea st around entire bag.

Rnd 10
Hdc in ea st down to end of side, work 2 Hdc in end st (at side of bag). Then continue around other side of bag by working a Hdc in ea st to other end (side edge) then work 2 Hdc in end st.

Rnd 11-27
Hdc in ea st around. End at side of bag with a Sl St. (Flat measurement approx. 12” long at this point.)

Rnd 28
At side of bag edge, Ch 2, *Sc […]