How to Prevent Dash Lines on Back of Knitting

I am trying to knit a blanket with knits and purls. When I knit, I get Dash Lines going across wrong side of blanket, but when I purl I get Dash Lines on other side of blanket, which makes both sides of blanket look bad. I know how to do this right when only using knit stitch, but not with knit and purl. I want to only have these Dash Lines on one side of blanket. How do I do that?

Are you knitting one row and purling the next row (stockinette stitch)?
In that case you could always change colors on a knit row and it would put the dots on the purl side.
Or are you mixing knits and purls in a checkerboard pattern?

Your info helped. It sounds like I need to knit first row of color change to avoid Dash Lines. My pattern was one row knit 4 and purl 2 across and next row purl 2 and knit 4 across. I don’t see how my pattern will work with color change unless I change it a little to knit one whole row every time change colors. Is that what I need to do?

Yup, that’ll do it. I don’t know of an alternative.

Yep. Do your color changes on the RS. Unless you double knit the back will never look exactly the same.