Large needle knitter

Hello all! I love to knit with large needles. I’m trying to knit individual squares for a blanket. How can I determine the number to cast on using size 19 needles and 3 ply yarn? Appreciate any assistance.

Plies don’t mean much in today’s world. You can have a fingering weight or bulky weight that are 3 ply so it’s best to tell us what weight the yarn is and gauge.
http://www.purlbee.com/2-ply-4-ply-why-ply/

That said…everybody knits at different gauges. The best way to get the size you want is by doing a swatch and then measuring to see if its what you want. Cast on 20 or 25 depending on the gauge of the yarn and knit in the stitch you want to use.

Usually 3 ply weight yarn is very thin like sock or baby yarn, and size 19s are much too big for it unless you’re going to use 4 or 6 strands together. If it’s thick yarn that has 3 strands, that’s better suited for the needles, but isn’t much of of a descriptor for the yarn.

Anyway, everyone’s gauge varies, so whatever yarn and needles you have, you need to cast on about 10 or 12 sts and work a few inches, then count how many stitches you have in an inch, and multiply that by how wide you want the squares to be.

Size 19? Those are huge. I’d look at super bulky yarn myself.

Yes, that’s what I have a baby skein and tripled it. I did my cast on and it’s working out fine. Thank you all!