the whys and hows of pressing seams open

design, fabric, quilting, sewing

Oh my. You would not believe the number of emails I’ve gotten over the years about our instructions to press seams open. I’ve been surprised at how unsettling those three words are to some. So when a Craft Nectar reader emailed me this week asking me to write a post about it I immediately realized that it was long overdue.

So let’s break this down.


First of all, we realize that we’re probably the only people in the quilting world who press seams open. In the garment construction industry, pressing seams open is a standard practice. It makes sense. It prevents seams from becoming bulky and uncomfortable by pressing them to the side as most quilters do. We also find it easier to align seams when the seam allowances are pressed open.

Our theory is that this practice originated with hand piecing, hand quilting and older methods of manufacturing batting that had less structural integrity — meaning that it didn’t stay put once is was in a quilt. So if you think about it hand piecing generally has 8-12 stitches per inch at best. Usually the stitches are larger so it’s easier for batting to sneak out between the gaps between stitches. Similarly, hand quilting is usually less dense than machine quilting so there’s a higher probability that fibers might migrate from the batting layer to the quilt top.

In our minds, if you’re going to hand piece or hand quilt, it makes sense to press your seams to the side. Among the quilters that we teach and meet at shows, there’s probably 1 in 100 who hand pieces and maybe 2 in a 100 who hand quilt. As a result we write our patterns for the majority of quilters who machine piece and machine quilt their quilts.

Sewing machines typically sew with stitches that 15-20 stitches to the inch so the likelihood that batting would migrate is much smaller. New batting holds together better and dense quilting stabilizes the batting further. We have quilts that we regularly have washed in a washing machine for the past 20 years with seams pressed open and we have seen no fiber migration. However, if you would prefer to press your seam open, go right ahead.


“So how exactly do you do it? Do you finger press first or do you try to slide the iron to open the seam allowances?” These are always the next questions. I’ll explain how we do it, but your situation will depend on how much hand and arm strength you have, how easy it is for you to maneuver your iron and your general coordination. As always, our method may not work for you. We’re just sharing what works for us.

Although I am left-handed and Bill is right-handed, we both are comfortable using both hands for pressing seams. Bill, who’s a bit of a show-off on this subject, uses the tip of the iron to open up the seams and quickly slides the iron across the seam allowances. There are very few people who can master this technique so I wouldn’t advise trying.

On the other hand, I hold the iron in my right hand and spread the seam allowances apart with my left hand. Be sure to keep your hand far enough away from the iron that you won’t get burned if there’s a steam burst. It might seam awkward at first but like most things you don’t even think about it after you’ve done it for awhile.

If that technique makes you nervous, you can do a quick slide of your fingers to spread the seam allowances open, really a quick finger press, and then slide the iron down the center to make the creases flat.

As we mentioned in Modern Quilts Illustrated, Mary Ellen’s Best Pressed is fantastic for pressing so if you’re iron doesn’t have a good steam burst, a spritz of Mary Ellen’s might be helpful.

[Note: We don’t know Mary Ellen, don’t receive any money from her and buy her products the same way you do — with hard-earned cash. We just promote her spray because it’s a really good product.]

16 thoughts on “the whys and hows of pressing seams open

  1. Weeks, I press both ways, depending on the project. However, I much prefer pressing open for the reduced bulk factor and the fact that I can match seams much better with seams pressed open. My technique is just like yours. Thanks for this post. Lora

  2. As a longarmer, I always press my seams open and I always get asked ‘how do you get it so flat?’. I hate SID so there really is no need ever to press seams to one side.

  3. I’m like Lora and Lydia, I press both ways, hand piecing is always to one side though. I don’t usually use steam for pressing, I just use a dry iron, saves having burnt fingers, although I will use a burst of seam for my final press.

  4. Thanks for addressing this. It is an interesting topic and the pictures are great.

    Could you also address how you can quilt in the ditch with this pressing method. The “ditch” would be between the two pieces of fabric, it seems to me, and the quilting in the ditch would be in the seam itself over the stitching threads and not on the fabric. So, if you are planning to ditch quilt, would you still press the seams open? I thought, and correct me, please, if I am wrong, that the “ditch” is created by pressing the seams to one side. If you are not planning to ditch quilt, then the open seams work well. What’s your opinion on this?

    All the best,
    Caryl in Evanston

  5. Thank you so much Weeks! This was just the kind of information I was looking for. I’ve always pressed to the side and am trying it this way for my current project. I will be anxious to see the results. Thanks again!

  6. @Caryl – I’m not a fan of stitching in the ditch. I don’t think it adds anything to the quilt and there’s always a better quilting pattern that will. I think that people usually do it because they don’t know what else to do. BUT just because I’m not a fan doesn’t mean you can’t be! The ditch usually refers to the seam and stitching in the ditch refers to stitching immediately adjacent to the seam. I really think it would depend on the construction of the quilt. If it had a lot of points, like a star, I’d still press open because stitching in the ditch would be a nightmare and the quilt would be super lumpy. If you are worried about pulling the seam open by sewing right next to it, I could see the argument for pressing to one side. As I said, it’s personal preference.

  7. Thank you! I’m 90 percent finished with my very first quilt and now wish I’d pressed those seams open instead of to the side. It would’ve made quilting all the layers together a bit easier in a few “bulky” places. I appreciate you sharing your insight on seam pressing and I can’t wait to start my next quilt top and press those seams open! :-)

  8. I am not sure where the idea of pressing to the darker side came from or who first took open seaming from garments to quilting, but a lot of “modern” quilters like Elizabeth Hartman press their seams open.

  9. I didn’t press open on my seams on a huge quilt, and I regret it. I blindly followed the teaching of the person who initially taught me.
    Never again!
    Pressing seams open make the quilts look so much better. I have had no problems with any batting coming through.
    However, I may gift the large one I am unhappy with and remake it with the seams open . . . . which means I get to go fabric shopping. How sad.

    I have also started making a test quilt, doll sized to get my head around the techniques. These get gifted to local welfare services for thier clients children.

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