How to Block a Sweater

Twenty years ago I knit my first adult sweater. It was a vision in moss stitch, knit in classic, undyed wool. The word “heirloom” hung in the air. But when it was finished I noticed it pulled terribly on the bias, and every time I stretched it where I wanted it, it bounced back into place like an elastic waistband. I was crushed. Defeated. Why?!? [Raises fist to the sky.]

If I knew then what I know now, I would have wet blocked the sweater and all would be right with the world. But I didn’t; I frogged it because I didn’t know better.

It’s hard to believe there was a ever a time when I didn’t block my sweaters. I not only didn’t block them, I didn’t even know blocking was a thing. In a recent workshop I taught, I showed a book from the 1940’s that I was given when I first learned to knit as a child (which was much later than the 1940’s, just to be clear) and talked about how much I didn’t know about blocking back in the day. I said, “I don’t think blocking was even mentioned in these books” and then flipped right to the page that explained blocking in full detail. Whoops. I must have been so excited to start knitting that I skipped right over the other important chapters.

Blocking is for so much more than aesthetics, but even if that were its only function I’d still do it. It makes an enormous difference in the way a garment feels, drapes and wears; it can turn a dud into a dynamo.

While there are a few different ways to block a sweater (or any hand-knit garment), I’m a die hard believer in the traditional wet blocking method. I’ll tell you why:

  1. Yarn is dirty. It doesn’t look dirty, mind you, but the journey from sheep to skein, from skein to dye bath, from dyer to your needles… it’s right up there with the Incredible Journey (old movie reference, anyone?). A proper bath helps to rinse away excess chaff and residue.
  2. Excess dye. This isn’t always an issue, but some yarns hold excess dye that may rub off onto the clothes you’re wearing underneath (vibrant colors can be especially tricky this way). A good soak and wet blocking will help the fiber release extra dye and keep it off your clothing (and your skin).
  3. Relaxing the fiber and stitches. Soaking your finished hand-knit sweater allows the fiber to relax. This settling process evens-out inconsistencies and encourages the stitches to get comfortable. Not only will it help hide flaws (hooray!), but it it will smooth and help to define the stitch pattern. Perky cables will transform into elegant curves. Lacework will become art. And humble stockinette becomes a thing of beauty. An unblocked sweater looks anxious – blocking will help it relax.
  4. Drape, darling. When you eliminate excess residue, wash away remaining dye and give the fiber a chance to relax, something brilliant happens: drape. A sweater that hangs nicely on the body is a sweater you’ll reach for again and again.
  5. And, most of all, fit. It is impossible to sing the praises of wet blocking without also cheering its role in sweater fit. Sweater patterns are meant to achieve the intended fit AFTER you block them, not before. That’s why gauge swatches are meant to be blocked, as well, since the goal is to give you insight into how the sweater will behave after you’ve blocked it. A sweater that doesn’t appear to fit quite right might just need a good soak to reach its full potential.

So how do you wet block a sweater?

You’ll need:

Prior to blocking, weave-in all the ends of your sweater or other knit project, and leave excess tails rather than trimming them off completely. This allows the fiber to shift with blocking and prevents the tails from popping out of place. (I like to do one last trim of any fledgling tails after the sweater is blocked and dry.)

Fill your basin with lukewarm or cool water (not hot) and the proper amount of wool wash, as described on the bottle. Submerge your sweater in the water and gently press it and/or turn it as needed so the water is able to fully penetrate the garment. Avoid the temptation to agitate or handle it too much.

Let your sweater soak for at least 30 minutes; sometimes I’ll let mine soak longer if I’m busy doing other things.

Note: If portions of the sweater still look dry because they weren’t fully submerged, I recommend gently turning the sweater in the basin and giving it another ten minutes or so to soak.

When soaking is complete, drain away the excess water and squeeze in a very gently wringing motion to help eliminate some of the water in the fiber. Be cautious here – you don’t want to stretch or disfigure your stitches.

Lay your sweater out neatly on a towel (be sure not to use a white or light colored towel in case of dye transfer) and roll the sweater up, pressing firmly to draw water into the towel.

Using flat blocking mats and blocking pins (I love the Knit Blockers for sweaters – they are a revelation!), lay your sweater flat on the mats (facing up, usually) and straighten/smooth the edges. Draw the sleeves out flat if you can (in this case they were a bit too long, so I folded them). Use blocking pins to tack down the collar, pin alongside cable or lace detail and help to mark and define curves, lines or angles in the sweater that you want to train into place or enhance. Some sweaters need more pins than others – it will depend on the stitch pattern and yarn. Just use what you need. If the sweater is already happy to lay flat and smooth without pins, then that section may not need them. But be careful: don’t stretch the garment too much; pull it flat until it’s smooth and you achieve the correct measurement across the chest, arm, and down the length of the body (refer to the schematic in the pattern for these measurements), but no further. The goal of blocking isn’t to stretch your sweater; you want to relax the fiber and enhance the stitch pattern.

Leave your pinned sweater in a warm place with good circulation to speed up the drying process (I don’t recommend blocking outside in full sun due to the possibility of bird/animal visitors and potential issues with the sun bleaching out non color-safe dyes; it’s rare but does happen).

When the sweater is mostly dry, but still damp, turn it over and allow the other side to face up Blocking pins are usually not necessary at this point, but can be used again if the sweater still needs support.

Avoid blocking directly on a dress form as it will stress the neckline/shoulders and cause the sweater to stretch in length more than necessary.

When your sweater is dry, trim any excess tails from ends you previously wove-in, add buttons (if applicable) and wear it proudly.

A note about after-care:

Blocking sweaters isn’t just for a new knit; you can also block your older sweaters to refresh them and help them return to their original shape.

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