Ask Patty: Purl Power – Modern Daily Knitting

It’s time to nerd out over stitch anatomy and examine what that little wrap of yarn, the head of the stitch—otherwise known as the purl bump—does to our fabric.

First up, a letter that struck me right in my heart and gave me flashbacks to my early knitting days.

Big Pearl Energy

Dear Patty,

I am a new knitter, and I knit a scarf pattern from a beginning knitting book. It was all stockinette and no matter what I did, it just rolled into a tube. Someone told me that I needed to add a few stitches of garter on either side, so next scarf I tried that. The garter just folded to the back and the scarf still rolled up. So, I get it, it will roll. So, to the queen of “why” I ask: 1) WHY does it roll, and 2) WHY did the knitting book have a scarf pattern in stockinette?

Rolling my eyes,


Dear Virginia,

I’m going to start by answering question #2. If this were a radio interview, there would now be a warning to turn your volume down. Ready, here goes . . . I DON’T KNOW! Tthe same thing happened to me. I still have that very first striped scarf I ever knit, and yes, it is a tube.

And I don’t know why knitters try to pretend we can outsmart this fact of nature with a few garter stitches at the side, or worse, blocking! It’s best to accept the laws of nature, though: the sun will rise each morning, my mother will always see the glass as half empty, and your stockinette will curl.

But why? That’s your question #1.

It’s all about the energy of that purl bump, or the head of the stitch.

A few years ago, I wrote a column about gauge (me, writing about gauge? What are the odds?) where I talked about what that purl bump does to different fabrics. But a picture is worth a thousand words (which is my word limit for each column).

Here’s a front view of stockinette. Here we see all those flat little Vs.

If we look at one column of stockinette, we can see it’s basically a chain—loops pulled through loops.

And if we look at this in profile, you can see the purl bump, the head of the stitch, wrapping to the back.

This is a weird thing to say, but with stockinette you have a fabric that is wider on the public side (the knits) than the private side (the purls). When all the purl bumps are pulling to the same side of the work, your fabric will curl!

How does garter work, you may be asking? (Okay, maybe you weren’t.) Well that leads me to seemingly unrelated, but oh so related, second email.

In the MDK Shop

The game changer of gauge checkers. When we tried out the Akerworks swatch gauge, with its transparency and its grippy little teeth to hold it in place, that was it. Thanks for your purchases. They support everything we do here at MDK.

Shortcuts aren’t always.

Dear Patty,

I know if you knit a gauge swatch flat and you will be knitting in the round, your gauge will not be accurate. If knitting stockinette in the round, why not knit a flat swatch in garter stitch? You will have a row of knit stitches on the right side and a row of knit stitches on the wrong side. Essentially you have a knit stitch on top of a knit stitch in the previous row which is stockinette in the round.

Always looking for a shortcut!

Oh, Gwen, Gwen, Gwen,

A shortcut you say? Well, your desire for a shortcut led me to knit for you three separate swatches. (Are you happy now?) Here we have a stockinette swatch knit flat, a stockinette speed watch (simulating, knitting in the round), and a garter swatch. All are worked over the same number of rows. Let me pause and repeat that—all are worked over the SAME number of rows.

DISCLAIMER: These tiny swatches were knit for photography. If I were swatching for a sweater, they would be much larger. Do what I say, not what I do. Thank you.

Here too, the purl is why swatching differently than you intend to knit the project is no shortcut.

First up, our stockinette swatch knit flat—alternating rows of knits and purls.

My flat stockinette gauge: Just shy of 15 st per 4″/10 cm and 18 rows per 4″/10 cm. The entire 23 row swatch measures 5″/13 cm tall.

Next up, our stockinette speed swatch. This is worked on circular needles. After each RS row, we slide our knitting to the other side of the needle, bring our yarn to the back and knit another row. So, we create stockinette the same way we do when working in the round—knitting every row in the same direction, without turning.

My speed swatch stockinette gauge: 15 st per 4″/10 cm and 20 rows per 4″/10 cm. The entire 23 row swatch measures 4 ½″/11.5 cm tall

Finally, we have the “shortcut” swatch, our little squatty friend—garter.

My garter gauge: 13 1/2 st per 4″/10 cm and 30 rows per 4″/10 cm. The entire 23 row swatch measures 3″/7.5 cm tall

Since garter is knit every row, you might think it would be the same as a speed swatch, but it’s all about those stacking purl bumps.

Here’s a column of garter shown from the front:

With garter, what we see on the face of our fabric is a row of knits and a row of purls. Looking at that column from the side shows the purl bumps alternating between pulling to the front and pulling to the back.

Looking at garter from the side explains why not only it is a thicker fabric, but it has a much tighter row gauge. Instead of a smooth interlocking chain like our stockinette, we have a squatty zigzag.

Some knitters swear they can make a perfect square with garter by working twice the number of rows as they have stitches. For many, two rows of knitting (one purl ridge) are the same height as the width of one stitch. For me it wasn’t quite square, but pretty close.

So, gentle reader, although every knitter is different, and if every knitter did the same experiment they would get slightly different results, one thing remains constant—the best “shortcut” in swatching is to swatch the way you will work the project.

But, since I did all that swatching for you, I hope you feel like that kinda saved you time.

Patty in your Pocket

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