That’s what your Benchmark project is saying to you, and it will be well worth the small amount of time it takes to knit a swatch with your yarn before you cast on. There are key things you can learn from a swatch too. I’ll give you a few pointers here, along with some “extra credit” and insights:
Why all the fuss?
Getting your gauge correct means your sweater will turn out the size that you select! The cast on numbers of the pattern were determined based on the given gauge, so you need to match the size of your stitches to that of the pattern for your sweater to result in the same size.
Swatching shows you what your yarn will look like as knitted fabric, before you knit your sweater. That’s always exciting for me!
You can bind off the swatch and give it a soak to see how your yarn will block and finish. Plied Yarn blooms and softens when soaked. Knitting North Ave fingering at a 5-stitches-per-inch gauge for this sweater results in a fabric with some little gaps and looseness to it. When you soak your finished sweater, the fibers will expand and fill in those gaps. Magic!
You don’t have to waste yarn by swatching. Simply unravel your swatch and incorporate the yardage into your project.
Basic stockinette swatch—here’s how to do it!
Check out the Benchmark pattern info. The gauge to achieve is 20 stitches within 4” in stockinette fabric. A needle size 6 is suggested. Simply cast on about 30 stitches (more than 20 is preferred so your swatch is wider and you can isolate 20 regular stitches to measure), using that size needle, and knit the RS rows and purl the WS rows to make stockinette fabric. Knit about 28 rows this way. Then get out a ruler or gauge tool and count the number of stitches you made within 4” across. Stay away from the edges where stitches can be wonky. Measure 4” in the center of the swatch.
Do you need to adjust? If you’re fitting more than 20 stitches into 4”, then your gauge is tight. Increase the needle size and knit another inch of fabric so that you can check it again. You don’t need to begin a new swatch! If you aren’t fitting 20 stitches into 4”, then your gauge is loose. Decrease the needle size, knit another inch, and check it again.
Determine the needle size that makes your 20 sts gauge with the yarn you are using. The needle suggested in the pattern is what the designer used with Plied Yarn North Ave to consistently get 20 sts gauge. Your knitting is unique to you, and it is specific to each project you make.
Got your needle size determined? Write it down on the pattern! This is the needle you will use for the body and sleeves of the sweater (whenever the pattern says to use the larger needle). Ribbings are made with a smaller needle. You can use the size suggested in the pattern for these edgings, or adjust up or down relative to the needle you are using for the body (2 or 3 sizes smaller).