When you look at the beautiful yarn in a shop or when you read a knitting or crocheting pattern how do you know what you will get when you work it up? There is so much promise in a pattern or a ball of yarn but there is also a lot of room for disappointment and stress from not getting the results you expected or the pattern promised.
Swatching is a very simple exercise that is designed to help you realize the full potential in your project with the minimum of bother. I used to think that swatching was a waste of time. I just wanted to get on with it! Swatching and even worse, blocking the swatch, just takes SOOOO long. Except it really doesn't. I finally realized after so many projects started and frogged and started again and frogged again that I really needed to take the time to swatch. Especially because I like to modify and make up patterns. It was so much easier to predict how a pattern would develop if I just took one evening to make a swatch and block.
So what is swatching? It's the simple process of knitting up a small sample of your pattern with the needles you intend to use for your project. This will give you an accurate idea of how the yarn behaves, how your gauge relates to the gauge given in the pattern and what you'll need to change in order to execute your pattern accurately.
Gauge is really what you are looking for at the most basic level of this exercise. Your gauge is what determines how tight your final fabric will be, how it drapes, and what size your project ends up. If you're anything like me, I tend to knit with a lot of tension and my fabrics tend to be very tight at my default knitting gauge. So often my finished project is smaller than I intend, unless I swatch first. Then I know I can switch to slightly bigger needles or knit more loosely than I normally do. The swatch I make first is also a great way to check to see if I'm keeping that gauge consistent throughout my project by using it as a comparison.
Here are a photo of our handspun yarn that we are selling in the 2 ply 8WPI weight that I swatched and blocked using steam.
The smaller square is knit on size 5 needles and the bigger square is knit on size 10 needles. The amazing thing is that they have almost the same about of stitches per inch, 18 vs 20, but have a totally different drape and hand. The bigger square also has a few more stitches cast on and is a couple of rows taller. So you can see that this is an important exercise to see what you can get out of a few yards of yarn. The smaller square feels dense and tight and the smaller square feels drapey and soft. So similar but so different!
Each pattern and most balls of yarn will tell you what gauge they intend for you to knit. That way you know what your fingers can accomplish and what your yarn can do for you!