Hey y’all, Melissa of Blank Slate Patterns here to talk with you about choosing and sewing knit fabrics. The Pocketful of Posies dress is a knit dress, which makes it comfortable and draped, but if you don’t choose the right knit fabric, you could have a stretched out mess on your hands. And differentiating between different types of knits can be confusing to a lot of people, particularly when buying online.
Now, I happen to be a knitter as well as a sewist, so part of what I’m going to talk about is related to how the stitches are formed, because that helps explain the differences in the fabric.
Knit fabrics are made of a combination of knit and purl stitches. The basic difference between those is whether the yarn is carried from stitch to stitch on the right or wrong side of the fabric. For knit stitches the yarn is carried on the back side. With purl stitches the yarn is carried on the front side.
In the picture below, you can see the horizontal yarn carried on the wrong side of the fabric. This fabric is formed by knit stitches on the right side and purl stitches on the wrong side.
This method of knitting the right side and purling the wrong side is how jersey knit is formed. The picture above is a sweater knit, but if you look really closely, you can see the same stitch pattern in the jersey knit below.
Because the thread is always carried on the wrong side of the fabric, jersey knits are not the stretchiest type of knits. Some, like the one pictured above, have spandex in them to improve stretch. Others, like sweatshirt fleece, barely stretch at all.
Another property of jersey knit because of this knit right side/purled wrong side is that it tends to curl toward the right side parallel to the selvedge and toward the wrong side perpendicular to the selvedge. You can see how the fabric in my picture is curling along the cut edge.
Depending on the thread content of the fabric, jersey knits can be fairly stable or quite stretchy. Cotton or silk jerseys typically don’t stretch very much, which jerseys that contain high percentages of spandex, rayon or bamboo stretch a lot. Those jersey blends also often have a lot of vertical or 4 way stretch, and that can make them unsuitable for the Pocketful of Posies dress because the weight of the jersey may cause it to stretch too much vertically and not hold its shape.
In the picture above, the jersey knit is yarn dyed gray. Most jersey knits with a print on them are printed on the right side, much as quilting cotton is printed. Occasionally you will find yarn dyed print jersey, which has the print on both the right and wrong sides. This is most typical for striped prints.
Interlock knit is a type of double knit fabric. Without going into super technical details, it’s kind of like two pieces of jersey knit back to back with the same thread.
Because of this, it is stretchier than jersey, and it looks the same on the front and back side, as the yarn is carried in the middle between the two knit sides. This also means interlock is typically a little thicker than jersey, and that it doesn’t curl. Interlock is the fabric I recommend to people who have never worked with knits before – it’s stable, usually has good stretch and recovery, and is generally the easiest knit to work with.
Ponte (pon-tee) or ponte de roma is a type of interlock knit, made with a blend of synthetic fibers.
Rib knit alternates knit and purl stitches on the same side of the fabric, then on the other side the knit stitches get purled and the purl stitches are knitted. So for example a knit pattern for ribbing might read knit two, purl two, repeat on the right side and purl two, knit two on the wrong side.
This forms the vertical ridges you can see on the fabric above. Because the yarn has to be switched from front to back so often, rib knit is also very stretchy. Also because of the even distribution of knit and purl stitches on the front and back side, rib knit typically looks the same on both sides and does not curl. Rib knit is great for collars and necklines, because it stretches a lot and because it adds stability to jersey knits in those areas.
Purchase the Sew With Me: Pocketful of Posies Dress Video and Pattern to see me demonstrate two methods for attaching rib knit hem bands.
Those are the main types of knit – hope this helps you when you’re shopping. But after you’ve purchased your fabric, what about how to sew it? Did you know you don’t need a special sewing machine to sew knits? You absolutely don’t, and in the video for the Pocketful of Posies dress you’ll see me sewing it up on a regular sewing machine using a zig zag stitch.
My top tips for working with knits:
DON’T STRETCH AS YOU SEW!
If you stretch the fabric, it will end up wavy looking and you don’t want that. Let the machine feed the fabric through, and if you’re sewing a stable fabric (like the interfaced part of the Pocketful of Posies pockets) to a stretchy fabric, keep the stretch fabric against the feed dogs when you sew.
USE A ZIG-ZAG STITCH
The way you deal with stretchy fabric/non-stretchy thread is to make sure your needle is doing some sideways motion. This is why a zig-zag stitch is perfect for sewing knits – the back and forth movement adds extra slack to the thread, so it doesn’t break when the fabric is stretched.
Sometimes even when you aren’t pulling the fabric, you’ll notice slight stretching and wavy seams. The culprit is often the presser foot/feed dog combination on your sewing machine. Sometimes this stretches the fabric just slightly as it is sewn, even if you’re not stretching it. There are a few ways to combat this. First of all, look for a presser foot pressure adjustment on your machine – it’s often a knob on top – and lower the pressure. This solves the problem for me on my machine.
If you don’t have a presser foot adjustment or it doesn’t fix the stretching, there are some other things you can try. You can try putting transparent tape on the bottom of your foot, so that the fabric slides easier. You can try putting tissue paper under your fabric (against the feed dogs) to try to achieve the same thing. You can try a walking foot, which “walks” across the fabric, reducing the chance for stretching.
Finally, if you’re running into issues with thread breakage or skipped stitches, it’s probably your needle. Universal needles can handle most knits, but thread breakage and/or skipped stitches are a sign you need to switch to a jersey or ballpoint needle.
So take these tips and the Sew With Me: Pocketful of Posies Dress Video and Pattern to have a stress free sewing with knits experience.