Free Knit Diamond Mosaic Cushion Cover Pattern Using Bernat Blanket Yarn

There is something deeply satisfying about a project that manages to look far more complicated than it actually is. The diamond mosaic cushion cover is exactly that kind of knit — geometric, striking, and seemingly intricate, yet built on a technique that even intermediate knitters will find approachable once they understand the rhythm. When you pair that pattern with Bernat Blanket yarn, the result is a cushion cover that feels as luxurious as it looks, with a velvety texture that makes the mosaic diamonds pop beautifully against a contrasting background.

This free pattern will walk you through everything you need to know, from materials and gauge to finishing techniques. Whether you are looking to refresh your living room, create a heartfelt handmade gift, or simply challenge yourself with a new knitting technique, this project delivers on all fronts.

Why Bernat Blanket Yarn Is Perfect for This Project

Before diving into the pattern itself, it is worth talking about the yarn, because the choice of Bernat Blanket yarn is not incidental. It is central to what makes this cushion cover so appealing.

Bernat Blanket yarn is a super bulky weight yarn (typically classified as size 6) made from 100% polyester. It has a chenille-like texture that gives it an incredibly soft, plush hand feel — almost like knitting with a cloud. Because of its bulk and stitch definition, mosaic colorwork reads exceptionally clearly in this yarn. The color blocks are bold and clean, and the slip stitches that define the mosaic technique stand out with real visual impact.

It is also a practical choice. Bernat Blanket yarn is machine washable and dryer safe, which matters enormously for home decor items like cushion covers. You want something that can survive regular use, the occasional spill, and a pet who has decided the cushion is theirs now. This yarn handles all of that without complaint.

The color range is another major selling point. Bernat Blanket comes in dozens of shades, from bold jewel tones to soft neutrals to playful variegated options. For a two-color mosaic pattern, you want high contrast between your main color (MC) and your contrast color (CC). Think cream and charcoal, navy and sand, dusty rose and slate, or even a rich burgundy against oatmeal. The contrast is what makes the diamond geometry sing.

Understanding Mosaic Knitting

If you have never worked mosaic colorwork before, here is the good news: it is one of the most beginner-friendly colorwork techniques available. Unlike stranded colorwork or intarsia, mosaic knitting only requires you to work with one color at a time per row. The “colorwork” effect is achieved through strategic slipping of stitches from previous rows, which carries the contrast color up through the fabric without ever having to hold two strands simultaneously.

The fundamental rule of mosaic knitting is simple. You work two rows with your main color, then two rows with your contrast color. When you encounter a stitch that belongs to the color you are not currently working with, you slip it purlwise with the yarn held in back (on right side rows) or in front (on wrong side rows). This carries the previous color up through the fabric, creating the illusion of intricate stranded colorwork.

The diamond pattern used in this cushion cover is a classic mosaic motif. The repeating diamond shapes are created by a staggered slipping sequence that, after a few rows, becomes almost meditative in its regularity. Once you have worked through one full repeat of the diamond, your hands will know what to do.

Materials You Will Need

To knit this diamond mosaic cushion cover, gather the following materials before you begin.

Yarn: Bernat Blanket yarn in two colors. You will need approximately 220 yards of your main color (MC) and 220 yards of your contrast color (CC). This accounts for a cushion cover sized to fit a standard 18-inch by 18-inch cushion insert with a slight amount of negative ease, plus a comfortable margin for finishing and weaving in ends. If you plan to make a larger cover, increase your yarn quantities proportionally.

Needles: US size 11 (8 mm) straight or circular needles. Circular needles can be helpful even for flat knitting when working with bulky yarn, as the cord distributes the weight of your work more comfortably.

Additional supplies: Two stitch markers, a tapestry needle for seaming and weaving in ends, scissors, and an 18-inch by 18-inch cushion insert. You may also want a row counter, particularly while you are learning the mosaic repeat, as keeping track of which row you are on matters in colorwork knitting.

Gauge

Gauge: 11 stitches and 20 rows = 4 inches in mosaic pattern using US size 11 (8 mm) needles.

Gauge matters more than many knitters initially expect for a cushion cover. Too loose and the cover will sag and lose its shape. Too tight and it will be stiff and difficult to slip over the insert. Work a gauge swatch before beginning, and do not skip this step even if you feel confident in your tension. Bernat Blanket yarn is forgiving in many ways, but individual knitters vary significantly in how they hold their yarn, and a difference of even half a stitch per inch will affect the final dimensions meaningfully over 18 inches of fabric.

If your gauge is off, adjust your needle size accordingly. Going up a needle size will loosen your gauge; going down will tighten it.

Abbreviations

Before working through the pattern, familiarize yourself with these abbreviations.

MC — main color. CC — contrast color. CO — cast on. BO — bind off. RS — right side. WS — wrong side. k — knit. p — purl. sl — slip stitch purlwise. wyib — with yarn in back. wyif — with yarn in front. rep — repeat. st/sts — stitch or stitches. pm — place marker. sm — slip marker.

Pattern Notes

This pattern is worked flat in two separate pieces (a front and a back) and then seamed together on three sides with the cushion insert placed inside. The fourth side is closed using a slip stitch seam or your preferred method after the insert is in place, making it easy to remove the cover for washing.

The mosaic diamond pattern is worked over a 16-stitch and 32-row repeat. Your total cast-on includes a border of two stitches on each side worked in garter stitch (always knit, every row) to give the edges a clean, stable finish. These border stitches are always worked in whichever color you are currently using and are not slipped.

Read all pattern notes before beginning, and always slip stitches purlwise unless stated otherwise.

The Diamond Mosaic Pattern

The pattern is based on a 16-stitch repeat. For an 18-inch cushion cover at the stated gauge, you will cast on 52 stitches: two border stitches on each side, plus 48 stitches for three full repeats of the 16-stitch motif.

Cast on 52 stitches using MC.

Work 4 rows in garter stitch (knit every row) using MC to create a bottom border. This gives your work a grounded edge that mirrors the top border you will add at the end.

Now begin the mosaic diamond pattern. The pattern is written out row by row for one complete 32-row repeat below. After completing the first repeat, continue working the repeat until your piece measures approximately 18 inches from the cast-on edge, ending after Row 32 of the repeat. Then work the top border and bind off.

Row 1 (RS, MC): K2 (border), k8, sl1 wyib, k7; rep from to last 2 sts, k2 (border).

Row 2 (WS, MC): K2, k7, sl1 wyif, k8; rep from to last 2 sts, k2.

Row 3 (RS, CC): K2, k7, sl1 wyib, k1, sl1 wyib, k6; rep from to last 2 sts, k2.

Row 4 (WS, CC): K2, k6, sl1 wyif, k1, sl1 wyif, k7; rep from to last 2 sts, k2.

Row 5 (RS, MC): K2, k6, sl1 wyib, k3, sl1 wyib, k5; rep from to last 2 sts, k2.

Row 6 (WS, MC): K2, k5, sl1 wyif, k3, sl1 wyif, k6; rep from to last 2 sts, k2.

Row 7 (RS, CC): K2, k5, sl1 wyib, k5, sl1 wyib, k4; rep from to last 2 sts, k2.

Row 8 (WS, CC): K2, k4, sl1 wyif, k5, sl1 wyif, k5; rep from to last 2 sts, k2.

Row 9 (RS, MC): K2, k4, sl1 wyib, k7, sl1 wyib, k3; rep from to last 2 sts, k2.

Row 10 (WS, MC): K2, k3, sl1 wyif, k7, sl1 wyif, k4; rep from to last 2 sts, k2.

Row 11 (RS, CC): K2, k3, sl1 wyib, k9, sl1 wyib, k2; rep from to last 2 sts, k2.

Row 12 (WS, CC): K2, k2, sl1 wyif, k9, sl1 wyif, k3; rep from to last 2 sts, k2.

Row 13 (RS, MC): K2, k2, sl1 wyib, k11, sl1 wyib, k1; rep from to last 2 sts, k2.

Row 14 (WS, MC): K2, k1, sl1 wyif, k11, sl1 wyif, k2; rep from to last 2 sts, k2.

Row 15 (RS, CC): K2, k1, sl1 wyib, k13, sl1 wyib; rep from to last 2 sts, k2.

Row 16 (WS, CC): K2, sl1 wyif, k13, sl1 wyif, k1; rep from to last 2 sts, k2.

Row 17 (RS, MC): K2, k1, sl1 wyib, k13, sl1 wyib; rep from to last 2 sts, k2.

Row 18 (WS, MC): K2, sl1 wyif, k13, sl1 wyif, k1; rep from to last 2 sts, k2.

Row 19 (RS, CC): K2, k2, sl1 wyib, k11, sl1 wyib, k1; rep from to last 2 sts, k2.

Row 20 (WS, CC): K2, k1, sl1 wyif, k11, sl1 wyif, k2; rep from to last 2 sts, k2.

Row 21 (RS, MC): K2, k3, sl1 wyib, k9, sl1 wyib, k2; rep from to last 2 sts, k2.

Row 22 (WS, MC): K2, k2, sl1 wyif, k9, sl1 wyif, k3; rep from to last 2 sts, k2.

Row 23 (RS, CC): K2, k4, sl1 wyib, k7, sl1 wyib, k3; rep from to last 2 sts, k2.

Row 24 (WS, CC): K2, k3, sl1 wyif, k7, sl1 wyif, k4; rep from to last 2 sts, k2.

Row 25 (RS, MC): K2, k5, sl1 wyib, k5, sl1 wyib, k4; rep from to last 2 sts, k2.

Row 26 (WS, MC): K2, k4, sl1 wyif, k5, sl1 wyif, k5; rep from to last 2 sts, k2.

Row 27 (RS, CC): K2, k6, sl1 wyib, k3, sl1 wyib, k5; rep from to last 2 sts, k2.

Row 28 (WS, CC): K2, k5, sl1 wyif, k3, sl1 wyif, k6; rep from to last 2 sts, k2.

Row 29 (RS, MC): K2, k7, sl1 wyib, k1, sl1 wyib, k6; rep from to last 2 sts, k2.

Row 30 (WS, MC): K2, k6, sl1 wyif, k1, sl1 wyif, k7; rep from to last 2 sts, k2.

Row 31 (RS, CC): K2, k8, sl1 wyib, k7; rep from to last 2 sts, k2.

Row 32 (WS, CC): K2, k7, sl1 wyif, k8; rep from to last 2 sts, k2.

Repeat Rows 1 through 32 until your piece measures approximately 18 inches from the cast-on edge. End after completing a Row 32.

Work 4 rows in garter stitch using MC for the top border. Bind off all stitches loosely using MC.

Make two pieces. The back panel is identical to the front panel. You can use the same mosaic pattern on both sides for a fully reversible cover, or work the back in a simple stockinette or garter stitch in one of your two colors for a simpler finish.

Finishing

Weave in all ends carefully before seaming. With Bernat Blanket yarn, a tapestry needle with a large eye works best. Weave the ends in different directions for a few inches so they do not pull loose over time.

Block both pieces lightly if desired. Because Bernat Blanket is 100% polyester, wet blocking will have minimal effect, but steaming with a damp cloth and a warm iron held just above the surface can help the pieces relax and lie flat. Do not place the iron directly on the yarn, as polyester is sensitive to high direct heat.

Hold the front and back pieces with wrong sides facing together. Using your main color yarn and a tapestry needle, seam three sides using whichever method you prefer. Mattress stitch gives a near-invisible join and is a beautiful choice for the front-facing edges. For the bottom and side seams that will be hidden, a simple whipstitch works perfectly well and goes faster.

Once three sides are seamed, insert the 18-inch cushion form. The slight negative ease built into the pattern dimensions ensures the cushion cover fits snugly and maintains the shape of the insert without sagging. Seam the remaining open side closed using mattress stitch, or if you prefer easy removal, consider using a row of large snap fasteners or a length of ribbon laced through eyelet holes worked into the top border of each piece.

Sizing Adjustments

The beauty of a pattern built on a 16-stitch repeat is that it scales easily. To make a larger or smaller cover, simply adjust your cast-on in multiples of 16, plus the 4 border stitches (2 on each side). A 20-inch cushion cover would require approximately 58 stitches; a 14-inch cover approximately 40 stitches. Remember to adjust your yarn quantities as well — more stitches mean more rows, and both