Tips and Techniques for Hems.

So much goes into the construction of a great-fitting, wearable garment. After all the measuring, cutting, and sewing, often the final make-or-break step is the addition of the hem. Many patterns give specific recommendations with regards to hem width and type of stitching. However, as you get more and more comfortable with sewing clothing,
you will likely find yourself making extensive modifications, and even going out on your own completely and drafting your own patterns. As a designer, it will be up to you to choose the best hemming parameters to get just the look you are after.
When it comes to hems, I have access to an excellent collection of reference material…my closet. It may not be organized, and I probably don’t wear half the stuff in there, but it is a great starting point for deciding how a garment should be finished.

Between the items I have made and the items I have bought, there is a little bit of everything. If you aren’t a clotheshorse, just head up to the mall with camera or notebook in hand. Chances are you will find multiple garments similar to the piece you are making, and you can get all the hemming inspiration you need.
There are no set rules when it comes to hemming, but I’m going to give some general width, folding, stitching, and timing guidelines. I’ll also address some special situations, and provide some of my favorite tips and tricks for hemming perfection.
Hem Width
The width of the hem greatly affects the way a finished garment hangs. For flowing designs made from light to medium weight fabrics, a narrow (about 1/8” to 3/8” wide) hem is most appropriate. Very narrow rolled hems can be made with a serger, and also with conventional sewing machine with a special foot attached (see article for more info). Thinner hems not only move with the fabric, the are relatively easy to apply to thin or slippery fabrics and/or curved edges. Here are some examples from my closet:

Slightly wider hems (about 3/8″ – 1/2″) give a crisper edges and a bit more structure to shirts and dresses, as shown on the bottom edge of this peasant top:

Tailored dresses and skirts require a relatively thick (1¼” to 2”) bottom hem to make the garment hang properly. In my youth, I made a way-too-short little shift dress out of white stretch denim. To make it a bit longer and more modest, I took out the recommended wide hem, and resewed a very narrow hem. Not only did it look awful, I spent the entire night pulling on it to compensate for the thin hem rolling and creeping up my thighs. Needless to say that one is NOT in my closet any more. Here is an example of a proper dress with a nice wide hem:

On many casual pants, skirts, and dresses made from medium weight fabrics, you will find a bottom hem that is ¾” to 1” wide. This average width gives a nice solid finish, and generally makes the piece hang nicely:

When it comes to pants, however, my personal preference is to make hems a bit on the wide side. It just seems that they wash and wear better when they have the extra material responding to the pull of gravity.

Folding
When working with light to medium weight woven fabric (my substrate of choice 99% of the time), I generally make double-folded hems. This eliminates the need to edge finish, and also gives a very clean look to the inside of the garment. For narrow hems, I make a fold about ¼” from the raw edge and press. Then I make a second fold that is right in line with the raw edge of the fabric. For wider hems, I make an initial ¼” fold, then make a second fold the desired distance from the first fold.

For thicker woven fabrics, a double-folded hem is often too bulky. In this case, it is best to make a single fold with the raw edges finished (either with a flatlock stitch on a serger, or a zig-zag or overcasting stitch on a conventional sewing machine).

When working with knits, I find single-folded hems to be much easier to manage than double-folded hems. Since knits do not fray, the raw edges don’t even have to be finished. I do find that edge finishing goes a long way to keep the edges from curling in trickier knits (for more knit hemming tips, see below). Another great finish for knit edges is the rolled hem.

A metal gauge can be used to measure out the width of the seam allowance. In most of my ePatterns, I include a printable cardstock folding template that can be used to make the exact folds called for in the design. You can easily make a custom folding template just by drawing a parallel line that is spaced the desired width from the edge of the cardstock. I’ve also put together a free pdf tutorial that contains both curved and straight universal folding templates marked with a range of widths:

Stitching
Hems can be sewn into place by machine or hand stitching. For most casual fabric and design combos, straight stitching with a sewing machine is perfectly acceptable. If you want to downplay the appearance of the line of stitching, use a thread color that is slightly darker than your fabric. However, nice, even machine stitching with a contrasting thread color can add detail to a hem. Decorative stitches can also be used to add pizazz and function in one fell swoop.

For more tailored garments and formal fabrics, blind stitch hemming is preferred. Blind stitching can be accomplished easily and quickly by machine if the proper foot is used. The edge-finished fabric is folded once at the desired position of the stitching, and folded a second time at the bottom edge of the garment (the first fold should be about ¼” from the finished edge).

The stitching is made near the edge, and at specific intervals the needle will jump over and “catch” the fold. The blade in the center of the foot facilitates perfect alignment during stitching.

Machine blind stitching is commonly used on drapes, slacks, men’s slacks, and big fluffy wedding dresses. A bit of the thread may be visible on the outside, but it is not obvious because of the position of the hems (especially if you use matching thread).

For hemlines that are more noticeable, (like on a knee-length skirt), blind stitching by hand can give practically invisible, couture quality results. I like to think of it as zig-zag stitching, going up from the edge and into the garment, then back down, and so on and so forth. The trick is to catch as little of the garment as possible so that the stitching does not show on the outside. To reduce bulk at the stitching points, hem tape or lace (sold in the packaged notions near the bias tape) can be machine sewn to the edge of the fabric, and then blind stitched to the garment.

Timing
As Kenny Rogers once said, “You got to know when to hold ‘em, know when to fold them…” OK, he was talking about cards, but the same sentiment applies to hemming. Sometimes it is best to sit back and wait a spell before putting in a hem. For both woven and knit garments, “flowy” type styles have a tendency to lengthen after construction. Bias cut styles, in particular, can grow several inches on the hanger! For this reason, it is best to let such garments “rest” in a hanging position overnight before hemming.
If your garment is relatively straight, and you are using stable wovens and knits, the hems can go in right after construction. In fact, I often calculate the needed length (based on measurements of myself or other nice fitting garments), and put in the hem folds before sewing. I find it much easier to press a flat edge, and it is so nice just to be able to refold and put in my stitching at the end of the construction process.
Special Situations
Curved hems
It can be a bit tricky to get even folds along an aggressively curved edge. With narrow hems, you can use your fingers and your iron to manipulate the fabric into place prior to stitching. The wider the hem, the trickier it is to get the curved edge to lay nicely against the garment. Convex shaped arcs should be slightly gathered to “shrink” the edge. You can gather with basting stitches, or if you have a serger, turn the differential feed setting up a notch or two when edge finishing. Before stitching, press the folded edges and make sure that no lumps, bumps, or puckers are visible on either side of the garment. Concave curves can sometimes be accommodated by gently stretching the raw edges of the fabric. Snips can also be used to compensate, but use them sparingly, and make sure they do not extend beyond the hem fold. Another option is to use flexible bias tape to finish the curved hem, or create a facing that fits exactly.

Hemming Knits
Knits – eeeek! Actually, they aren’t that hard to hem, you just have to be mindful of the stretch. First off (as with any knit seam), you should definitely use a ball-point needle to prevent jabbing holes in the fabric. The next thing to consider is the direction of the stretch. Hems are almost always running parallel to the direction of the stretch, which means the stitching should be somewhat stretchy so that it will move with the fabric. The amount of stretchiness needed depends on how tight the garment will fit. A long flowing knit skirt could probably be finished with a regular straight stitch, no problem. The bottom openings on a pair of leggings, however, would need to be very stretchy to slip over the foot and then hug the ankles. My go-to stitches for such knit hems are the regular zig-zag stitch and the staggered zig-zag stitch. I think they look cute, and they hold up to some serious stretching.

My machine actually has a knit stitch but I don’t use it for hemming because it isn’t very attractive and it seems to distort the edge. If you absolutely must have straight stitching on a hem that is going to be subjected to stretching, use long, loose stitches, 100% polyester thread through the needle, and a stretchy thread like Wool Nylon in the bobbin. This combination will minimize the chances of the stitches “popping” during wearing. It also cuts on the distortion caused by small, tight stitching. Also, avoid tugging and pulling during the stitching process. Just let the fabric feed through the machine feed through the machine without any help other than gentle guidance to keep the hem stitching even.
Knits are notorious for shifting and curling during stitching, and sometimes a little stabilization is all it takes to make those edges behave. One of my favorite products for narrow hems is Wash-Away-Wondertape. It is sticky on both sides (but won’t gum up your needle), and makes a perfect ¼” fold. For wider hems, I use fusible tapes like Heat & Bond Lite or Stitch Witchery. These products keep the hem fold in place, and minimize stretching during stitching.
Hemming Fabrics that Fray
For fragile fabrics like silk dupioni, chiffon, and lamé, it can be hard to even get a nice clean edge to fold, let alone stitch. I have found that giving the edges a nice clean cut, followed by immediate (but light) treatment with fray-check makes all the difference in the world.

In summary, there are lots of factors involved in determining the best possible way to hem a garment. For guidance, check out ready made garments. There are no specific hemming rules, just make sure you are finishing your item in a manner that fits with the fabric and the function of the design. And don’t be afraid to get a helping hand from tools/notions like hem gauges, hem tape, fusible products, and Fray Check! They can truly make the difference between a wimbly-wombly disaster and a crisp, clean, professional looking hem.