How to change color in garter stitch/how to add stripes in garter stitch by clydknits.about :

Switching colors in knitting. To add a new color of yarn in the middle of a row, simply drop the yarn you were working with, and begin working with the new color as you would if you were changing colors. Knitting with 2 colors on the same row or round dates to at least the 1500's. The museum of london collection boasts a lovely child's mitten that dates to the tudor era.

Just a little hook right that we will put. After knitting an entire row of the new color, you can untangle the knot and weave the tail into the fabric. Knit a plain round before you switch colors in ribbing.

Changing yarn color or adding a new ball of yarn is. No tying, nothing difficult at all. Insert the needle into the first stitch, loop the new colour over the tip of the right hand needle and knit the first.

Take the yarn in the previous color (in my case it is the white yarn) and put it on the left side. Keeping the tail of the new color in place. Here too we cross the yarns again.

When you are done making your color changes or adding your new skein of yarn of the same color, you should do four things. Give the new tail a good tug to pull down the loop around your knitting needle and create a stitch. Hold the working end of the yarn in your usual way.

In the image below you can see how the yarn twists. A short video demonstrating how to change colors by adding a new yarn at the beginning of a row of knitting without messy knots by designer patricia cantos. Once the yellow is pulled to the side take the white yarn and twist it over top the yellow and knit as you normally would.