Preventing seam separation
 

Hi all! I just finished quilting a channel pattern with 2 inch spacing. In the past I have had seam separation of my piecing when I grossly underquilted (as a newbie). I do not want to experience this again. I'm wondering if 2 inch spacing will be supportive enough to prevent separation? One of my pieced seams that runs the entire length of the quilt is smack dab between two lines of quilting, with no intersecting lines of quilting. I'm especially concerned about this channel, and am considering doing something decorative between those lines, but would prefer not to, aesthetically. Advice appreciated!

I wonder if the problem could be with the piecing, rather than with the quilting. Perhaps you need more stitches per inch? Seams can also come apart if the thread is weak, or if the seam allowance is too small. If your fabric has a loose weave, you may also need a bigger seam allowance. I wouldn't expect the seams to come apart merely because the quilting is less dense.

I was thinking about the piecing as well. I had that problem when my pieced seams didn't have the accurate 1/4"

Having seems come apart on a gifted quilt is so embarrassing and frustrating. Ask me how I know? Part of the seem problem, I believe, is mishandling (especially large quilts) quilts when they are wet and not properly removing them from the washer. I always give a card with my quilts with directions for washing and preserving the integrity of the quilt. I am now convinced that no one reads these directions.

When repairing my great granddaughter's quilt, which had open seems, I decided to use a design on my Brothers' machine that is a wavy line. I used this stitch on all of the long seems. It is easier than SITD and it is quite nice. Here is the back of a quilt where I used this stitch.
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I try to make my quilting as evenly dispersed within a quilt to give it support and stabilization. Remember the rule, form follows function?

Perhaps make a row of "beads" across the seams to set them. You just curve one way and then the opposite cured way to form the beads along straddling the seam. The second pass the opposite direction makes the beads. Kind of serpentine , if you know what I mean?

Yes the wavy line is the first pass and sewing back the other direction makes the "beads". You cross over as you go.

I would also say that it may be a piecing issue. The max distance apart you can quilt is established by your batting. The packaging will give you this info, but it assumes that the piecing is secure. Before quilting it's a good idea to look over all your seams to ensure that you have a minimum of 1/4". This gives you an opportunity to take a bit larger seam if you find any skimpy ones.
Another thing to consider is the fabric weave. Fabric that has a looser weave, such as homespun or lesser quality quilting cotton can fray or pull apart.
If you piece by machine, you probably won't have an issue, but the seam length normally used is 2.5 or smaller.
These issues can be mitigated by heavier quilting, and if you are worried about a specific seam, then definitely quilt over it. There are some great suggestions above.

FMQ would help when quilting as you could quilt over the seams too. I never stitch in the ditch, I don't think it helps anything. I quilt about a 1/4" from the seam, usually where the seam allowance is. I try to make sure I don't have any skimpy seams after I sew a seam. Easiest to fix then. I set my machines stitch length on 2.

Thank you everyone!

The quilt that I had a problem with I used quality quilting fabric, but I was inexperienced and did random straight-line quilting from edge to edge on all different angles. But not nearly enough. So some parts of the quilt had several inches without any quilting.

For this quilt I did Slightly larger than 1/4 inch seam allowance, should that be enough insurance that it will hold up? My stitch length was 3, I didn't know I should piece with smaller stitches!! Also, the fabrics are all interlock (t-shirt), flannel and thermal fabrics (it is a memorial quilt made from clothing, which I've never done before). My sashing at the seam I'm worried about is all interlock, so maybe this should be reassuring since it doesn't fray??

It depends a lot on the quality of your piecing stitches. I used to fix up vintage sewing machines for charity and often needed to adjust machines to get a good, secure stitch.

Secure stitching requires that the top and bobbin tensions be set correctly. The tensions need to be balanced so that the threads meet in the middle. When they don't meet in the middle, one thread lies flat against the fabric and can be easily pulled out. In addition to being balanced, the tensions need to be somewhat tight. If you have a balanced stitch where the top and bobbin tensions are loose, you can pull apart the seam and easily see lots of the stitching thread in the seam. When the tensions are tight the way they should be, very little of the thread is visible when you pull the seam apart.

Stress on the seams comes from everyday handling, sitting on a quilt, washing and drying a quilt, hanging, etc. Quilting reduces the stress on seams. The closer together the quilting lines, and the more often quilting crosses over seam lines, the less stress there is on the seams.

In your particular situation, the seam within the channel will be stressed more than others in the quilt because you have a long seam line that has no quilting stitches running over it. If the stitches used in piecing the seam are tight and secure, then there will be enough support so that no single thread is ever taking all of the stress. If, however, the piecing stitches are loose because of one of the reasons above, sooner or later the stress will be concentrated on a single thread and that thread will break.

Edit: Shortening stitch length does make for a more secure seam; however, it also adds thread to the seam and makes un-sewing more difficult. That would be my last resort if I couldn't get the tensions right on my machine.

This is very helpful! Considering that I am unsure whether or not my piecing stitches were at perfect tension (although they seemed ok, neither top nor bobbin were stretched flat), would you still err on the side of caution and find a way to add more quilting? I'd prefer not to, as I like the simple design I have done. But it would be better than a disaster down the road. Here is a picture of the channel I'm concerned about, if that helps!