How to block knitted garments

Ensure your finished knitwear looks its very best by blocking it properly. Jen Arnall-Culliford offers her expert advice

How to block knitted garments

The instruction to ‘block your knitting’ is often given at the end of the pattern for a knitted garment, but what does it mean, and why should you bother? At its simplest level, blocking your knitting means to wash and dry flat. Blocking can be absolutely transformative, smoothing out imperfections in your fabric and allowing you to shape your garment as desired.

What’s the difference between a slouchy beanie and a beret? Blocking. How do you make it easier to sew seams neatly? Block the pieces. Colourwork looking a bit lumpy? Block it. Knitted a lace shawl and it looks like a hair net? Blocking will turn this caterpillar into a butterfly.

For more finishing advice, see our beginner’s guide to how to block knitting projects, and how to block lace knitting, or if you’re blocking accessories such as socks and hats then check out our Top tips for blocking knitted accessories

Blocking vocabulary


Blocking is also sometimes called dressing, particularly when applied to lace shawls. It’s the act of stretching out the knitting to make the stitch pattern appear more clearly.


Using an iron and a damp cloth to flatten your knitwear. Some companies advise pressing your knits before seaming, and while this certainly works, I’ve found that the possible pitfalls far outweigh the benefits of speed. Pressing can result in knitted fabric being over-flattened and losing its bounce, and having a hot iron too close can easily scorch delicate yarns. Where the pattern suggests pressing, personally, I would always wet-block the pieces of knitting instead.


You Will Need

  • Bowl
  • Water
  • Wool wash
  • Foam blocking mats
  • Pins

Total time:

Washing your knits

Step 1

You’ve cast off the last stitch and woven in your ends, so it’s time to block. The first job is to thoroughly wet your garment. Use lukewarm water – not too hot, or you may felt the yarn, and not too cold or the water won’t penetrate the fibres. A teaspoon of wool wash or shampoo added to the water helps the water to wet the knitting, with the added bonus of cleaning off any dirt that may have accumulated while you worked on the project.

Step 2

Gently squeeze to remove any air pockets and ensure that the garment is completely soaked. I leave my knits in the water for about 20 minutes, so that the fibres have a chance to fully relax, but many consider this to be unnecessary.

Blocking leave garment to soak
Ensure that the garment is submerged and leave it to soak.

Step 3

Once your project is completely soaked, carefully remove it from the water. The wool will be weaker whilst it is wet, so take care to gather up the whole piece, not allowing it to stretch under its own weight.

Wool can absorb about a third of its weight in water, and combined with the weakening of bonds between fibres it’s all too easy to over-stretch. This is why instructions always say not to wring out or twist your wet knitting. Instead, you should gently squeeze to remove most of the excess water.

Step 4

To dry the garment further, either press it between two towels, or place it in a gentle spin cycle on your washing machine for 5-10 minutes.

Blocking avoid stretching the garment
Take care when removing your knitting from the water, as it could stretch under its own weight.

How to block sweaters and jumpers

Step 1

You will need an area away from potential dangers such as animals or small children, where you have space to lie your garment flat until it is completely dry. Ideally this should be on a surface into which you can pin. I use a thick, clean towel over our carpet, but you can also use a bed or foam blocking mats.

Blocking on foam mats
Foam mats are a good surface for blocking on, especially if pinning.


Step 2

Blocking is a bit like blow-drying your hair: you can cause fabric to sit in a way that’s not completely natural. Indeed, it works in the same way. Washing interferes with the hydrogen bonding between the protein chains that your hair (and wool) are made from. If you then dry your hair (or your knit) in a different configuration, the hydrogen bonds re-form to stabilise the new arrangement. The only down point is that you need to repeat the operation every time you wash it. So if your cardigan is a little bit tight, a firm blocking can make it wider, but you’ll need to do the same every time it goes through the laundry.

Lay your sweater flat, and spend some time ensuring that the measurements are correct. If your cardigan has buttons already, then do them up. If not, ensure that the bands are lying over each other to emulate how you intend to wear the cardigan (if it should button all the way down, then the bands need to be overlapped all the way down). Move the fabric so that the hem lies straight, with the sides folded neatly along the columns of shaping (if there is shaping). Check that both sleeves are angled evenly, and that the two sleeves are the same length (little differences can easily be tweaked here, by gently stretching one if required).

If there is any colourwork, use your fingertips to flatten and generally primp the stitches. Run your eye over any design features, and ensure that where relevant, they are symmetrical. If there is an edging, make sure that it is lying flat (or stand it up if that’s what’s required!). For folded collars, arrange them as you want them to be worn. If patterning such as a colourwork yoke is continuing from one side of a cardigan front to the other, line it up neatly across both fronts.

Blocking lie garment flat and leave to dry
Line up hems, buttonbands and sleeves, then leave to dry.

Step 3

If your sweater isn’t already conforming to the measurements provided in the schematic, you may wish to gently stretch it (it’s more tricky to make a garment smaller…). In this case, you will either need lots of pins, or a set of blocking wires and pins. There is a limit to how much you can stretch a garment without damaging it, and each yarn type and stitch pattern will vary. As long as you go slowly and take care, you should be able to add an inch or more without any trouble.

Start on one side, and either thread a wire up the side seam, or place plenty of pins, so that when you stretch the sweater, you don’t end up with a scalloped side edge! Then measure across to give the width you require and using either a wire again or pins, gently tug the garment to the desired size and pin firmly in place. Double-check that hems are still straight and that the rest of the garment is still lying correctly.

Step 4

Leave it to dry fully before unpinning.


Jumper boards

In Shetland, the most common method of blocking sweaters is to use a jumper board. This is a wooden frame that allows you to firmly stretch out a sweater to desired dimensions. They are usually adjustable for height and width. Sweaters are washed as normal, and then stretched onto the frame and allowed to dry. This works particularly well with Fair Isle designs worked in wool, and gives fantastically smooth fabric.