There are two primary forms of shaping that people talk about when they talk about bust shaping in knitting—vertical bust darts (or VBDs) and horizontal bust darts (or HBDs). Vertical bust darts are essentially a set of increases that add additional width to the bust beyond the shaping written into the pattern to allow room for a bust that is proportionally larger than the upper bust. Horiztonal bust darts, on the other hand, are essentially a set of short rows that add extra length just at the bust. HBDs aren’t typically written into sweater patterns because patterns assume that the natural stretch of the knitted fabric will be sufficient to cover the bust. There are lots of tutorials and information online and in knitting books about how to add HBDs (I’ve included some resources at the bottom of this post as well), but today I’m going to try to give some visuals to help you assess whether or not you need to add HBDs to your sweaters.
Me and My HBDs
I decided to try incorporating HBDs into my sweaters when I was working on my fit experiment sweater. When I was taking measurements for that sweater, I decided to compare the length of my back and my front by tying a piece of waste yarn around the point where I like my sweaters to typically fall and then measuring the length from the top of my shoulder to the yarn both at my back and my front. Thanks to those measurements, I discovered that my front is 5” longer than my back—that’s a pretty significant difference. Some people recommend adding enough short rows to compensate for the difference between your front and back measurements, but I decided to assume that my knitted fabric would comfortably stretch to cover a couple of inches of length and only added 3” of HBDs. This worked so well that I’ve continued to add the same amount of length via HBDs in every fitted sweater I’ve made myself since. At this point, I honestly can’t see myself knitting a sweater without HBDs unless it was meant to be worn open or oversized.
Do you need more length or just more width?
Amy Herzog argues in this post on her blog that many people think that they need HBDs to keep their sweaters from riding up in the front could resolve their ride-up problems by adding VBDs instead. The logic is that when knitted fabric has to stretch horizontally, it shrinks vertically, so that if a sweater has to stretch several inches across the bust, you’ll lose length at the front of the sweater and experience ride-up. Amy contends that using VBDs to add extra width to the front of the sweater will reduce the amount of stretching the sweater has to do across the bust and, thus, reduce the loss of length as a result of stretching. I think this makes good sense, and I think that if you are in the habit of knitting sweaters with 3-4” of negative ease and are having your sweaters ride up at the front, then you would probably benefit from adding VBDs to your sweaters before you try HBDs.
And there’s good reason to forgo HBDs if you don’t really need them. You have to be really careful with the way you work your short rows to keep them as invisible as possible, and sometimes they will still create a visible line in your knitted fabric. They can be difficult to work over certain stitch patterns or disrupt striping. And, of course, HBDs are another form of shaping that you have to figure out how to incorporate into your sweater, often with no guidance from the pattern itself. But the bottom line is that extra width isn’t going to solve everyone’s bust shaping issues—it certainly wouldn’t have solved mine. Amy suggests women with more than 2″ of difference between their back and front length measurements might need HBDs. I would agree, and I thought I would share some pictures that could help you make even more sense of your measurements.
A Case Study: The Old Navy Cardigan
For my money, one of the best indications of whether or not you could benefit from HBDs is by studying the way clothes tend to fit you. This sweater is a good example of the way that clothes tend to fit me. This is a cardigan I got at Old Navy a few years ago. From the front, it hits me mid-hip, which is were I typically like my tops to fall. And worn this way, it looks like it’s just a basic, V-neck cardigan. However, this cardigan is actually meant to be worn long through the torso and slightly loose. In my experience, the average length for the body of woman’s sweater from the hem to the underarm is around 14-16” long. This Old Navy Cardigan measures 18” from hem to underarm.
I consistently have problems with RTW tops being too short for me, which made me think that I just had a really long torso. But I don’t have an unusually long torso so much as I’m busty and need some extra length at the front. You can see proof of this when you look at how this sweater fits me from the side and from the back.
What you can see in these two shots is that while the sweater hits me at my mid-hip with a relatively smooth front, I’ve literally got piles of excess fabric hanging around the back of the sweater. And if I pull the hem of the sweater down so that the back lays smooth, I end up with an unintended and seriously undesired hi-low hem effect. Lovely!
This sweater fits me with about 1” of positive ease at the bust, so none of the way that this sweater fits is due to stretching at the bust. And in tops that do fit with too much negative ease at the bust, my experience has been that when they ride up, they actually ride up over the bust and bunch up a bit at the armpits as the top shifts to try to provide extra fabric for the bust. This cardigan doesn’t actually ride up—I can wear it all day like this, with the excess fabric piled up at the back, and not have to constantly adjust the front down. The big issue with the way that this cardigan fits me is that it is unbalanced, which means that the hem doesn’t fall evenly around my body. And while I could knit all of my sweaters to be 18” long before the armpit to make sure they’re an appropriate length in the front, the excess fabric at the back would become even more of an issue since hand-knit fabric tends to be thicker and more dense that RTW knits.
The Comparison: Two hand-knit cardigans with HBDs
When I add my standard 3” of HBDs to my hand-knit sweaters, those sweaters end up measuring 3” longer at the center front of the sweater than at the back or the side seams. So on my last two cardigans, I knit the body of the sweater to be 15″ long before the armhole shaping but added 3″ of bust darts to make the center front 18″ long. If you look at this flat shot of my recent Squared Cardigan, you can see the way that the front dips down longer than the back of the cardigan.
However, if you look at pictures of my recent Audrey in Unst cardigan (which has the same exact shaping as my Squared Cardigan), you can see that I’m not plagued with piles of excess fabric at the back of the sweater and that the hem of the sweater is balanced—it falls parallel to the floor all around my body. This cardigan already has plenty of width at the bust—I’m wearing it with about 1/2”-1” of positive ease at the bust—so my HBDs aren’t compensating for stretch across the bust. They’re just providing the bit of extra length I need at the front of a sweater.
So even though they take a bit of extra effort and can sometimes create a visible dart line, I think HBDs are totally worth the costs, especially since I’ve yet to produce a sweater that truly fits me well without them. If you’re wondering if you might benefit from HBDs, I say study your closet and pay close attention to how your clothes feel. And keep in mind that the short-row shaping method used in HBDs can be applied to other areas of the body (back, belly, butt, etc.) where you might need a bit more coverage. When you can finally wear something without having to tug it into place all day, the world is a brighter place!
HBD Reading List and other Resources: