Casting off the last stitch of a project you have been working on for weeks is particularly satisfying. The needles come out, the fabric goes slack in your hands, and the thing you have been patiently working on is finally finished.
Sometimes finished knitted or crochet projects can look slightly off. The edges might curl, one sleeve sits longer than the other and the lace pattern you worked so carefully doesn't look how you imagined. Blocking is almost always the missing step, rather than anything you have done wrong.
In this guide, we'll explain what blocking actually is, when you need to do it, how to wet block step by step, and how different fibres respond.
What is blocking?
Blocking means wetting or steaming a finished project, then shaping it and letting it dry in that shape. Water relaxes the fibres so they can settle into a new position, and once dry, they stay there.
It sounds almost too simple to make a difference, but it makes an enormous one. Stitches even out, edges lie flat, lace opens up, and measurements finally match the pattern.
Do you have to block everything?
You don't always need to block, but it helps more often than you would think. A dishcloth in cotton will be perfectly usable straight off the needles. A jumper knitted in pieces, on the other hand, is far easier to sew together once each piece has been blocked to size.
The pieces that benefit most are lace, anything with a stockinette edge that curls, garments made in separate sections, and shawls. If your knitting looks slightly uneven, there is no need to worry because blocking will probably help more than you think.
What do you need to wet block?
You don't need very much, and you probably already have most of it at home.
- A basin, sink, washing-up bowl or a bucket
- A gentle wool wash (water on its own still works fine)
- Clean, dry bath towels
- A flat surface that can get damp (foam blocking mats or some towels on the floor)
- Rustproof pins, so nothing marks or stains the fabric
- A tape measure, if you are blocking to the dimensions given in a pattern
Blocking wires can be useful for shawls and long straight edges, because they hold a whole edge in one clean line rather than in scallops between pins. They are a nice thing to add later rather than something you need on day one.
A step by step guide on wet blocking
Wet blocking is the most thorough method and is the one most patterns assume you are using. You will only need around half an hour of hands-on time, then a day or two for drying. Here is the whole process from start to finish.
Step 1. Fill the basin with cool water
The water should be cool or lukewarm, never hot. Sudden temperature changes and heat are what cause wool to felt, and felting is not reversible. Add a small amount of wool wash if you are using one, you don't need much, a capful is plenty.
Step 2. Submerge and leave to soak
Lower the piece into the water and gently press it under the surface until it stops floating. Don't swirl, rub or agitate it. Then leave it for about twenty minutes. The fibres need that time to absorb water properly all the way through, and a quick dunk will not do the same job.
Step 3. Lift it out and support the weight
Wet knitting is heavy and it will stretch if you let it dangle. Gather the whole piece into a loose bundle and lift it out with both hands underneath, supporting it like you would a sleeping cat. Squeeze gently to release most of the water. Never wring or twist it as this may cause many fibres to stretch.
Step 4. Roll it in a towel
Lay a dry bath towel flat and spread the piece out on top of it. Roll the towel up from one end with the knitting inside, like a Swiss roll, then press down along the length or stand on it. This pulls out a surprising amount of water. If the towel comes out soaked, repeat with another.
Step 5. Pin it out to shape
Lay the damp piece on your blocking surface and coax it into shape with your hands first, checking the measurements against your pattern, and then pin. Work from the centre outwards and place opposite pins as a pair, so the tension stays even rather than dragging in one direction. If you're using pins, make sure your blocking surface can be pinned. A foam blocking mat works great.
Use more pins than feels necessary. Pins spaced widely apart leave a scalloped edge, which looks lovely on a lace shawl point and less lovely on a jumper front. Take your time here, because this is the shape your finished project is going to keep.
Step 6. Leave it to dry completely
Ideally leave it somewhere with a bit of air movement, out of direct sunlight and away from a radiator. Most pieces take twelve to twenty-four hours, and thicker wool can take longer. Check underneath as well as on top, because the underside is usually the last part to dry. Try to keep the piece flat if you can.
Step 7. Unpin and admire
Only unpin when the piece is bone dry to the touch. If there is any dampness left it will relax back towards its old shape, and you will have done the work for nothing. Weave in and trim your ends now if you haven't already, and that is the project properly finished.
It's important to not worry about how your project looks until it is dry. Knitting looks strange and limp while wet, and it always looks worse before it looks better.
Are there quicker ways to block?
Yes, and both have their place.
Spray blocking is the gentler option. Pin the dry piece into shape first, then mist it thoroughly with water from a spray bottle until it is damp all the way through rather than just on the surface. Leave it to dry as you would with wet blocking. This suits pieces that only need a light adjustment, and it saves handling a heavy soaked garment.
Steam blocking is the quickest of the three methods. Pin the piece out, then hold a steam iron or handheld steamer a few centimetres above the surface and let the steam do the work. The iron must never touch the fabric. Steam is very effective on wool, but it should be avoided on plant-derived fibres like bamboo viscose, which can lose body if overheated.
Which fibres block best?
Wool is the star. It has natural memory and elasticity, so it takes a new shape readily and holds it. Alpaca blocks beautifully too, though it grows and drapes more than wool, so pin it gently rather than stretching it hard.
Cotton and linen respond well to wet blocking but have less spring, so what you pin is more or less what you get. Silk blends open up wonderfully and take on lovely drape. Superwash wool relaxes quite a lot more than untreated wool, so avoid overstretching it.
Worth knowing: synthetic yarns behave differently and blocking does not have the same effect, because the fibres do not respond to water in the same way. This is one of many reasons why we prioritise natural fibres.
Frequently asked questions
How long does blocking take to dry?
Usually between twelve and twenty-four hours, but it really depends on the yarn and the drying environment, for example a chunky wool would take much longer to dry than a fingering weight cotton yarn. Do not be tempted to unpin early, as damp knitting will lose its shape.
Can you block the same piece more than once?
Yes. Every time you wash a woollen garment you are effectively blocking it again. Reshape it while damp and lay it flat to dry.
Will blocking fix a jumper that came out too small?
Blocking causes a lot of yarns to grow, but it really depends on the fibre, some may stay the same. Blocking also evens out, settles fabric, and causes stitches to bloom (fluffing up a bit) so treat it as a finishing step rather than a rescue. Some fibres can be stretched during blocking if your project is too small.
Do I need special blocking mats?
No. A towel on a spare bed works perfectly well for most projects. Mats simply make pinning easier and are worth having if you block often.
Do you block before or after sewing up?
Before, if your garment is knitted in separate pieces. Flat, evenly shaped pieces are far easier to seam neatly than curling ones.
The step that makes your knitting look finished
Blocking is the difference between handmade and homemade. It is an unglamorous half hour at the end of a project, but it makes such a big difference, and it is the thing that makes people ask where you bought it.
If you have only ever skipped blocking, try it once on something small. Watching a curled swatch settle flat is oddly satisfying, and it makes the next project much easier to approach.
If you are unsure how a particular yarn will behave, or you would like a hand choosing something for a first project, do get in touch. We are always happy to chat about knitting.