What pure cotton does that wool does not
Cotton is an inelastic plant fibre, and every practical difference follows from that. It has no memory, so ribbing does not spring back and a heavy cotton jumper will gain length over a season of wear. It is heavier than wool for the same length, so a large garment feels substantial on the shoulders. It is cool against the skin, absorbs moisture readily, and takes a hot machine wash without felting – which is why it owns the summer top, the baby blanket, the dishcloth and the market bag. Mercerised cotton, treated to be stronger and shinier, has a crispness that makes it the standard choice for amigurumi and for anything where the stitch outline should be visible.
Choosing a cotton by project
- Summer tops and tees: matt 4 ply or DK cotton, knitted at or slightly below the ball band tension, in a shape with a little positive ease.
- Baby blankets and cardigans: soft DK cotton, machine washable and cool for a warm nursery.
- Amigurumi: mercerised 4 ply, worked on a small hook so stuffing cannot show through.
- Dishcloths and bath mitts: plain DK or aran cotton, worked in garter or a textured stitch, which scrubs better than stocking stitch.
- Bags and baskets: aran, chunky or super chunky cotton for structure that survives being filled.
- Lace shawls: lace or 4 ply cotton, which blocks to a sharp, crisp lace that does not fluff.
Tension, needles and quantity
Cotton punishes an optimistic swatch. Knit 15cm square, wash it exactly as you will wash the garment, dry it flat, and then measure – the fabric relaxes and often grows in the wash, and a jumper that fitted the swatch will not fit the body. Many knitters size down a needle for cotton garments to compensate for the drop. It is hard on the hands, since there is no give in the strand, so metal or well-polished wooden needles help and so do shorter sessions. Plan by metres: a summer tee often takes 700 to 1,200 metres, a pram blanket around 400 to 700, a dishcloth well under one ball.
Finishing, seams and care
Cotton does not block like wool. Wet blocking will even out your stitches and set the measurements, but it will not stretch a piece two sizes or fix uneven tension, so the fabric you knit is largely the fabric you keep. Seam with the project yarn using mattress stitch, and consider a firmer stitch or a row of crochet along shoulder seams to stop them stretching under the garment's weight. Wash finished cotton items on a normal cool to warm cycle, dry flat, and never hang a wet cotton garment – the weight of the water will add centimetres you cannot take back. Cotton softens with every wash, so a slightly stiff first impression is not a fault.
Cotton yarn questions
Is cotton yarn good for beginners?
Yes for flat projects like dishcloths and blanket squares, where the excellent stitch definition helps you see what you have done. It is less forgiving than wool for a first garment.
What is mercerised cotton?
Cotton treated to make it stronger, smoother and shinier, with crisper stitch definition and better colour uptake. It is the usual pick for toys and thread lace.
Does cotton yarn shrink?
It can shrink slightly on the first hot wash and it also tends to lengthen with wear. Wash your tension square first and follow the ball band.
What weight of cotton for a summer jumper?
4 ply or DK gives the best balance of coolness and drape. Aran cotton makes a heavy garment.
Where else should I look?
See cotton yarn for blends, or DK yarn across all fibres.
