How to Knit Mitered Squares CDD Spine Seam
Learn to knit mitered squares CDD spine seam in a solid yarn color. They are formed by decreasing stitches that meet in the middle. This mitered square uses the Center Double Decrease (CDD) technique to create a raised diagonal ridge down the center, which is my favorite way to knit mitered squares.
Start knitting these mitered squares with these detailed photo instructions, cast on cheat sheet, close-up video tutorial, and free printable written pattern.
Table of Contents
A Closer Look
- Easy to Memorize: After knitting a few squares, you’ll be able to easily remember the pattern without needing to refer to the instructions.
- Lays Flat: Because this square is comprised of all knit stitches, it easily lays flat.
- Are Mitered Square CDD Seams Reversible? At first look, this seems to be a reversible pattern. However, with this CDD technique, the right side of the work displays the ridged seam while the wrong side has a flatter texture.
Seamed Mitered Square Construction
Mitered squares are knitted by decreasing stitches to form a square with lines that meet in the middle, constructed with center decrease stitches. These decreases pull the sides of the square inwards to create the mitered effect.
For this seamed construction, we start with an odd number of stitches and work from the edges toward the center. The center double decrease (CDD) creates its neat, symmetrical square shape.
A basic Garter Stitch square tends to stretch lengthwise and lose its shape over time. However, as shown in the picture, the mitered square’s opposing stitch directions help maintain its shape and size. As such, its structural integrity is perfect for blankets and scarves that tend to get a lot of wear.
Watch Video Tutorial
How to Knit Mitered Square CDD Seams
Casting On
Begin by casting on an odd number of stitches. The number of stitches determines the total length of two edges of your square. Your yarn and needle size will determine the number of stitches required for your desired square size. I have created this helpful guide to determine the number of stitches to cast on.
Yarn DK #3 • Needle 6 US (4.0 mm)
| Square Size (inches) | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|
| Cast On Stitches | 27 | 37 | 45 | 55 | 63 | 73 |
| Yarn per Square (yards) | 19 | 25 | 31 | 37 | 43 | 49 |
Yarn Worsted #4 • Needle 8 US (4.5 mm)
| Square Size (inches) | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|
| Cast On Stitches | 25 | 33 | 41 | 49 | 57 | 65 |
| Yarn per Square (yards) | 19 | 25 | 32 | 38 | 44 | 51 |
Yarn Bulky #5 • Needle 10 US (6.0 mm)
| Square Size (inches) | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|
| Cast On Stitches | 19 | 25 | 31 | 37 | 43 | 49 |
| Yarn per Square (yards) | 10 | 14 | 17 | 21 | 24 | 28 |
Yarn Super Bulky #6 • Needle 13 US (9.0 mm)
| Square Size (inches) | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|
| Cast On Stitches | 13 | 17 | 21 | 25 | 29 | 33 |
| Yarn per Square (yards) | 7 | 9 | 12 | 14 | 17 | 19 |
Get Your Free Cheat Sheet
For this example, I am using bulky weight #5 yarn and size 10 US knitting needles. You can see in the Cheat Sheet above, to knit this 4×4 inch square I am casting on an odd number of 25 stitches onto my needle.
Slip Stitch Edge
To help sew our squares together, we are going to create uniform edges on all 4 sides of our square. To do so, we will slip the first stitch of every row.
Sl1P WYIF: Slip One Stitch Purlwise with Yarn in Front.
Right Side of Work (odd numbered rows)
While on the right side of your work, after slipping your first stitch, bring the yarn between the first and second stitches to the back of your work. Then knit all stitches until you get to the middle three stitches.
How to Calculate When to CDD
I personally do not use a stitch marker to figure out when it is time to decrease, since it requires a lot of moving back and forth. Here’s my calculation:
How many stitches to knit (including 1st slipped stitch) before CDD =
(# of Stitches – 3) / 2
For example, with 25 Stitches on my needle I am knitting 11 stitches before the CDD.
(25 – 3) / 2 = 11
For subsequent decrease rows on the right side of your work, you will knit one less stitch until it’s time to decrease.
Center Double Decrease
After you have knit all stitches until you get to the middle three, then knit your Center Double Decrease (CDD):
- Sl1P WYIB: Slip one stitch purlwise with the yarn in back;
- K2TOG: Knit the next two stitches together;
- PSSO: Pass the first stitch over (2 Sts Decreased).
Once you have decreased three center stitches into one, continue knitting all the way down the row.
Wrong Side of Work (even numbered rows)
On the wrong side of your work, Sl1P WYIF and knit all stitches to the end of the row.
Your knitted rows become increasingly smaller (and faster to knit) as each right-sided row is decreased by two stitches. Continue the following pattern until you have just five stitches remaining on your needle.
Last Row
With 5 Stitches Remaining on the Right Side of your work.
- Sl1P WYIF;
- CDD: Sl1P WYIB, K2TOG, PSSO (2 Sts Decreased);
- K1.
Finishing
- Cut the yarn and thread it through a tapestry needle;
- Slip the knitting needle out of the remaining 3 stitches;
- Thread the yarn tail through the open stitches and pull tight to cinch them closed;
- Finally, weave in the yarn tail to secure it.
Action Items
- Blocking: Before sewing your squares together, wet-blocking is highly recommended to create uniformed sized squares.
- Join your squares – Sew squares together with the mattress stitch.
- Colorwork Designs: Change yarn colors to create unique patterns.
Mitered Square Knitting Collection
Beyond this one-color CDD spine seamed pattern, get printable written instructions for these differently constructed and colorwork mitered patterns, as well.
Printable Knitting Instructions
Printable Knitting Pattern
Knitting pattern instructions of a Mitered Square with a CDD Spine Seam.
Materials
- Yarn - Any Gauge
Tools
- Knitting Needles - Appropriate Size for Yarn
- Tapestry Needle
- Scissors
Instructions
Cast On an Odd Number of Stitches
Your cast on edge will be length of two sides of your square. Therefore, decide how many stitches to cast on based on your yarn gauge and square size desired. See Cast On Cheat Sheet in the post above.
Knitting Pattern
Row 1 (Right Side):
- Sl1P WYIF, K to CENTER 3;
- CDD: Sl1P WYIB, K2TOG, PSSO (2 Sts Decreased);
- K to end.
Row 2 (Wrong Side):
- Sl1P WYIF;
- K to end.
Continue knitting rows 1 & 2 until 5 Sts Rem on the right side
5 Sts (Right Side):
- Sl1P WYIF;
- CDD: Sl1P WYIB, K2TOG, PSSO (2 Sts Decreased);
- K1.
Finishing:
- Cut yarn, thread tapestry needle,
- Slip knitting needle out of 3 rem sts,
- Thread yarn tail through the back of the 3 open sts and cinch,
- Weave in all yarn tails.
Notes
KNITTING TECHNIQUES & ABBREVIATIONS
- CO = Cast On Long Tail Method
- CDD = Center Double Decrease
- CENTER 3 = Center Three Stitches
- Dec = Decreased
- K = Knit Stitch
- K2Tog = Knit Two Stitches Together
- PSSO = Pass Slipped Stitch Over
- Rem = Remaining
- Sl1P WYIB = Slip One Stitch Purlwise with Yarn in Back
- Sl1P WYIF = Slip One Stitch Purlwise with Yarn in Front
- Sts = Stitches
- Weave In Ends
Kristen McDonnell
Author & Designer
After publishing her first knitting tutorial video, Kristen founded StudioKnit LLC. Enamored with teaching online, she films knitting lessons and designs from her vibrant production studio on Half Moon Bay’s California coast.
Kristen McDonnell is the author of the highly acclaimed book Knit Stitch: 50 Knit + Purl Patterns featuring vintage and unique designs.