I’m modifying this for a 3-9 month size. I cast on for the medium, but am knitting at a slightly tighter gauge (30 sts = 4 inches).

Other changes (added as I make them):

• Cast on 3 stitches in each armpit
• Knit stockinette portion for 5.5 inches. In last row increased 8 sts to 210 sts (14 repeats of leaf chart).
• After chart increase 2 sts before scalloped cast off.
• Pick up six stitches in each underarm.