Knitting is a method by which yarn is manipulated to create a textile or fabric. Knitting creates multiple loops of yarn, called stitches, in a line or tube. Knitting has multiple active stitches on the needle at one time. Knitted fabric consists of a number of consecutive rows of interlocking loops. As each row progresses, a newly created loop is pulled through one or more loops from the prior row, placed on the gaining needle, and the loops from the prior row are then pulled off the other needle.
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Knitting may be done by hand or by using a machine.
Different types of yarns (fiber type, texture, and twist), needle sizes, and stitch types may be used to achieve knitted fabrics with different properties (colour, texture, weight, heat retention, look, water resistance, and/or integrity)
Courses and wales
Structure of stockinette, a common knitted fabric. The meandering red path defines one course, the path of the yarn through the fabric. The uppermost white loops are unsecured and “active”, but they secure the red loops suspended from them. In turn, the red loops secure the white loops just below them, which in turn secure the loops below them, and so on.
Alternating wales of red and yellow knit stitches. Each stitch in a wale is suspended from the one above it.
Like weaving, knitting is a technique for producing a two-dimensional fabric made from a one-dimensional yarn or thread. In weaving, threads are always straight, running parallel either lengthwise (warp threads) or crosswise (weft threads). By contrast, the yarn in knitted fabrics follows a meandering path (a course), forming symmetric loops (also called bights) symmetrically above and below the mean path of the yarn. These meandering loops can be easily stretched in different directions giving knit fabrics much more elasticity than woven fabrics. Depending on the yarn and knitting pattern, knitted garments can stretch as much as 500%. For this reason, knitting was initially developed for garments that must be elastic or stretch in response to the wearer’s motions, such as socks and hosiery. For comparison, woven garments stretch mainly along one or other of a related pair of directions that lie roughly diagonally between the warp and the weft, while contracting in the other direction of the pair (stretching and contracting with the bias), and are not very elastic, unless they are woven from stretchable material such as spandex. Knitted garments are often more form-fitting than woven garments, since their elasticity allows them to contour to the body’s outline more closely; by contrast, curvature is introduced into most woven garments only with sewn darts, flares, gussets and gores, the seams of which lower the elasticity of the woven fabric still further. Extra curvature can be introduced into knitted garments without seams, as in the heel of a sock; the effect of darts, flares, etc. can be obtained with short rows or by increasing or decreasing the number of stitches. Thread used in weaving is usually much finer than the yarn used in knitting, which can give the knitted fabric more bulk and less drape than a woven fabric.
If they are not secured, the loops of a knitted course will come undone when their yarn is pulled; this is known as ripping out, unravelling knitting, or humorously, frogging (because you ‘rip it’, this sounds like a frog croaking: ‘rib-bit’). To secure a stitch, at least one new loop is passed through it. Although the new stitch is itself unsecured (“active” or “live”), it secures the stitch(es) suspended from it. A sequence of stitches in which each stitch is suspended from the next is called a wale. To secure the initial stitches of a knitted fabric, a method for casting on is used; to secure the final stitches in a wale, one uses a method of binding/casting off. During knitting, the active stitches are secured mechanically, either from individual hooks (in knitting machines) or from a knitting needle or frame in hand-knitting.
Basic pattern of warp knitting. Parallel yarns zigzag lengthwise along the fabric, each loop securing a loop of an adjacent strand from the previous row.
Weft and warp knitting
There are two major varieties of knitting: weft knitting and warp knitting. In the more common weft knitting, the wales are perpendicular to the course of the yarn. In warp knitting, the wales and courses run roughly parallel. In weft knitting, the entire fabric may be produced from a single yarn, by adding stitches to each wale in turn, moving across the fabric as in a raster scan. By contrast, in warp knitting, one yarn is required for every wale. Since a typical piece of knitted fabric may have hundreds of wales, warp knitting is typically done by machine, whereas weft knitting is done by both hand and machine. Warp-knitted fabrics such as tricot and milanese are resistant to runs, and are commonly used in lingerie.
A modern knitting machine in the process of weft knitting
Weft-knit fabrics may also be knit with multiple yarns, usually to produce interesting color patterns. The two most common approaches are intarsia and stranded colorwork. In intarsia, the yarns are used in well-segregated regions, e.g., a red apple on a field of green; in that case, the yarns are kept on separate spools and only one is knitted at any time. In the more complex stranded approach, two or more yarns alternate repeatedly within one row and all the yarns must be carried along the row, as seen in Fair Isle sweaters. Double knitting can produce two separate knitted fabrics simultaneously (e.g., two socks). However, the two fabrics are usually integrated into one, giving it great warmth and excellent drape.
In the knit stitch on the left, the next (red) loop passes through the previous (yellow) loop from below, whereas in the purl stitch (right), the next stitch enters from above. Thus, a knit stitch on one side of the fabric appears as a purl stitch on the other, and vice versa.
Knit and purl stitches
Two courses of red yarn illustrating two basic fabric types. The lower red course is knit into the white row below it and is itself knit on the next row; this produces stockinette stitch. The upper red course is purled into the row below and then is knit, consistent with garter stitch.
A dropped stitch, or missed stitch, is a common error that creates an extra loop to be fixed.
In securing the previous stitch in a wale, the next stitch can pass through the previous loop from either below or above. If the former, the stitch is denoted as a knit stitch or a plain stitch; if the latter, as a purl stitch. The two stitches are related in that a knit stitch seen from one side of the fabric appears as a purl stitch on the other side.
The two types of stitches have a different visual effect; the knit stitches look like “V”‘s stacked vertically, whereas the purl stitches look like a wavy horizontal line across the fabric. Patterns and pictures can be created in knitted fabrics by using knit and purl stitches as “pixels”; however, such pixels are usually rectangular, rather than square, depending on the gauge/tension of the knitting. Individual stitches, or rows of stitches, may be made taller by drawing more yarn into the new loop (an elongated stitch), which is the basis for uneven knitting: a row of tall stitches may alternate with one or more rows of short stitches for an interesting visual effect. Short and tall stitches may also alternate within a row, forming a fish-like oval pattern.
In the simplest knitted fabrics, all the stitches are knit or purl; this is known as a garter stitch. Alternating rows of knit stitches and purl stitches produce what is known as a stockinette pattern/stocking stitch. Vertical stripes (ribbing) are possible by having alternating wales of knit and purl stitches. For example, a common choice is 2×2 ribbing, in which two wales of knit stitches are followed by two wales of purl stitches, etc. Horizontal striping (welting) is also possible, by alternating rows of knit and purl stitches. Checkerboard patterns (basket weave) are also possible, the smallest of which is known as seed/moss stitch: the stitches alternate between knit and purl in every wale and along every row.
Fabrics in which the number of knit and purl stitches are not the same, such as stockinet/stocking stitch, have a tendency to curl; by contrast, those in which knit and purl stitches are arranged symmetrically (such as ribbing, garter stitch or seed/moss stitch) tend to lie flat and drape well. Wales of purl stitches have a tendency to recede, whereas those of knit stitches tend to come forward. Thus, the purl wales in ribbing tend to be invisible, since the neighboring knit wales come forward. Conversely, rows of purl stitches tend to form an embossed ridge relative to a row of knit stitches. This is the basis of shadow knitting, in which the appearance of a knitted fabric changes when viewed from different directions.
Typically, a new stitch is passed through a single unsecured (“active”) loop, thus lengthening that wale by one stitch. However, this need not be so; the new loop may be passed through an already secured stitch lower down on the fabric, or even between secured stitches (a dip stitch). Depending on the distance between where the loop is drawn through the fabric and where it is knitted, dip stitches can produce a subtle stippling or long lines across the surface of the fabric, e.g., the lower leaves of a flower. The new loop may also be passed between two stitches in the present row, thus clustering the intervening stitches; this approach is often used to produce a smocking effect in the fabric. The new loop may also be passed through two or more previous stitches, producing a decrease and merging wales together. The merged stitches need not be from the same row; for example, a tuck can be formed by knitting stitches together from two different rows, producing a raised horizontal welt on the fabric.
Not every stitch in a row need be knitted; some may be left “as is” and knitted on a subsequent row. This is known as slip-stitch knitting. The slipped stitches are naturally longer than the knitted ones. For example, a stitch slipped for one row before knitting would be roughly twice as tall as its knitted counterparts. This can produce interesting visual effects, although the resulting fabric is more rigid because the slipped stitch “pulls” on its neighbours and is less deformable. Mosaic knitting is a form of slip-stitch knitting that knits alternate colored rows and uses slip stitches to form patterns; mosaic-knit fabrics tend to be stiffer than patterned fabrics produced by other methods such as Fair-Isle knitting.
In some cases, a stitch may be deliberately left unsecured by a new stitch and its wale allowed to disassemble. This is known as drop-stitch knitting, and produces a vertical ladder of see-through holes in the fabric, corresponding to where the wale had been.
Right- and left-plaited stitches
The stitches on the right are right-plaited, whereas the stitches on the left are left-plaited.
Within limits, an arbitrary number of twists may be added to new stitches, whether they be knit or purl. Here, a single twist is illustrated, with left-plaited and right-plaited stitches on the left and right, respectively.
Both knit and purl stitches may be twisted: usually once if at all, but sometimes twice and (very rarely) thrice. When seen from above, the twist can be clockwise (right yarn over left) or counterclockwise (left yarn over right); these are denoted as right- and left-plaited stitches, respectively. Hand-knitters generally produce right-plaited stitches by knitting or purling through the back loops, i.e., passing the needle through the initial stitch in an unusual way, but wrapping the yarn as usual. By contrast, the left-plaited stitch is generally formed by hand-knitters by wrapping the yarn in the opposite way, rather than by any change in the needle. Although they are mirror images in form, right- and left-plaited stitches are functionally equivalent. Both types of plaited stitches give a subtle but interesting visual texture, and tend to draw the fabric inwards, making it stiffer. Plaited stitches are a common method for knitting jewelry from fine metal wire.
To start knitting, you only need two things: a pair of needles and a ball of yarn. If you want to finish a project, though, you’ll need a few more items. So what does an experienced knitter keep in a knitting kit?
A tapestry needle – The most basic tool in any knitter’s kit, a tapestry needle is a large sewing needle, with an eye big enough to accommodate bulky yarn. You’ll use the needle to weave in the tails of yarn left after you bind off your project.
Stitch markers – These small rings slip on your needles to mark particular points in your pattern. Some markers can be clipped directly onto a stitch if you need to mark a spot on the project itself to come back to later in the pattern.
Stitch holders – A stitch holder is like a large safety pin. When a pattern calls for you to set some stitches aside to come back to later, you will slip those stitches onto a holder.
Row counters – Many patterns require you to keep track of how many rows you have knit. Some counters slip onto your needle and have a number dial you change after each row. Some have a simple button you click. And, yes, there are smart phone apps for that.
A measuring tape – A lot of patterns call for a number of inches, rather than a number of rows. A flexible measuring tape will be indispensable, especially when making pairs of things, like mittens or sleeves. You don’t want to guess that your sleeves are the same length.
Needle caps – When you’re taking a knitting break, you can place them on the end of your needles to ensure no stitches slip off while your project is in your knitting bag. They can also be used to turn a double-point needle into a straight needle.
As for knitting needles, there are three types: the classic straight pair, double-point needles (sold in sets of 4 or 5), and circular needles. Keep knitting and you will eventually use each kind of needle. Some projects require the use of more than one kind.
Straight needles are used for most of your rectangular projects, like scarves and washcloths.
Circular needles are two needle heads connected to a cord. They are necessary for larger projects, like blankets. They are also used for projects that are worked in the round, like hats or the body of a seamless sweater. These needles vary by needle size and by cord length, from 9 inches to 60 inches. Frequent knitters might want to invest in a circular needle kit, which offers greater flexibility. Rather than buying a needle for each project, a kit allows you to customize the cord length and the needle size. Plus, if your project calls for changing needle size partway through, all you have to do is scrunch your stitches onto the cord and switch out the needle heads.
Double-point needles are used for smaller projects joined in the round, like mittens or the crown of a hat. Often, you will start a project on circular needles, then switch to double points as you get close to binding off.