Pro Tips: Knit Squares Blanket — Checkered Rainbow Tutorial

There is something deeply satisfying about a blanket made of knitted squares. Maybe it is the way each little block represents a small, completable task. Maybe it is the rhythm of the knitting itself, the repetition of simple stitches that allows your hands to work while your mind wanders. Or maybe it is the sheer joy of watching a pile of colorful squares slowly transform into something large enough to wrap around your shoulders on a cold evening. Whatever the reason, the knitted squares blanket is one of the most beloved beginner-friendly projects in the fiber arts world — and when you arrange those squares into a checkered rainbow pattern, the finished result is nothing short of spectacular.

This tutorial will walk you through everything you need to know to create a beautiful checkered rainbow knit squares blanket, from selecting your yarn and needles to casting on your first stitch, to joining your squares and adding a polished finishing border. Along the way, you will find professional tips that can make the difference between a blanket that looks homemade in the best possible way and one that looks genuinely stunning.

Whether you are a complete beginner picking up needles for the first time or an intermediate knitter looking for a satisfying, meditative project, this guide is written for you.

Why a Knit Squares Blanket Is the Perfect Project

Before we dive into the how-to, it is worth talking about why this specific format — individual squares joined together — is such an excellent choice for a blanket project.

The most practical reason is portability. A blanket knitted in one large piece can become unwieldy fast. The fabric gets heavy, it bunches up on your lap, and it can be awkward to carry around. Individual squares, on the other hand, are small enough to tuck into a bag and take with you anywhere. You can knit a square on your lunch break, during a commute, or while watching television. Each square is its own small project with a clear beginning and end, which gives you a sense of progress and accomplishment that can be harder to feel when working on a single massive piece.

There is also the matter of error correction. If you make a mistake on a traditionally knitted blanket, unpicking rows of dense fabric can be painful. With individual squares, a mistake on one square simply means setting it aside and starting a fresh one. You do not lose hours of work — only the thirty minutes or so it took to knit that particular square.

Finally, there is the design flexibility. Because each square is separate, you can play with color arrangement to your heart’s content before committing to a single layout. You can lay your squares out on the floor, shuffle them around, take a photo, move them again, and keep experimenting until the pattern feels exactly right.

Materials You Will Need

Getting your materials right before you start will save you frustration later. Here is a breakdown of what you need for a standard throw-size checkered rainbow blanket, which measures approximately 48 by 60 inches when finished.

Yarn: Choose a smooth, worsted-weight yarn for your first time making this blanket. Worsted weight is thick enough that you can see your stitches clearly, which makes it easier to catch mistakes, but not so thick that the squares feel heavy or stiff. For a true rainbow checkered effect, you will want at least six colors: red, orange, yellow, green, blue, and violet. You will also need a neutral — white, cream, or light gray works beautifully — to serve as the alternating “check” color. Plan on purchasing roughly 200 yards per color for the main rainbow shades and about 600 yards of your neutral.

Needles: For worsted-weight yarn, a US size 7 or 8 (4.5 to 5 mm) needle is typically appropriate, though you should always check your gauge. You can use straight needles, double-pointed needles, or short circular needles — whichever feels most comfortable in your hands for working small squares.

Notions: You will need a tapestry needle for weaving in ends and joining squares, a pair of sharp scissors, stitch markers, and a ruler or measuring tape for checking your gauge and square dimensions. A crochet hook in a similar size to your knitting needle can also be helpful for picking up dropped stitches and for certain joining methods.

Blocking materials: A blocking mat (or a few old towels covered with a clean sheet), rust-proof T-pins, and a spray bottle filled with water will help you enormously when it comes to finishing. Blocking is the step that transforms good knitting into great knitting, and it is especially important for a project with many seamed pieces.

Understanding Gauge and Why It Matters for This Project

Gauge is the number of stitches and rows you get per inch of fabric, and it matters more than almost any other factor when knitting a multi-square blanket. Here is why: if your squares are even slightly different sizes from each other, joining them will be extremely difficult and the finished blanket will look uneven. Every square needs to be exactly the same dimensions.

Before you cast on your first square, knit a gauge swatch. Cast on 20 stitches and work in your chosen stitch pattern (we will be using a simple garter stitch for this blanket) for about 25 rows. Bind off, wet the swatch, gently press it flat, and let it dry. Then count your stitches per inch and rows per inch.

For this blanket, each finished square measures 6 by 6 inches. If your gauge is 4.5 stitches per inch in garter stitch, you would cast on 27 stitches for each square. If your gauge is 5 stitches per inch, you would cast on 30 stitches. Do the math for your specific gauge before you begin, and write the number down somewhere you will not lose it.

Pro tip: Make all your squares in the same sitting or under the same conditions when possible. Knitting tension can change based on how relaxed or stressed you are, what you are watching on television, even the time of day. Consistent conditions help produce consistent squares.

Choosing Your Stitch Pattern

For a beginner-friendly blanket that still looks polished and professional, garter stitch is your best friend. Garter stitch is achieved by knitting every single row — no purling involved — and it produces a beautiful textured fabric with horizontal ridges that lies perfectly flat without curling at the edges. This is crucial for a blanket made of joined squares, because curled edges are a nightmare to seam.

That said, if you want a slightly different texture, seed stitch is another excellent option. Seed stitch alternates knit and purl stitches within each row and staggers them on subsequent rows, creating a bumpy, almost pebbly texture that is firmer and a bit more structured than garter stitch. It also lies flat.

For this tutorial, we will use garter stitch because it is the most accessible option and produces a clean, classic look that lets your colors take center stage.

How to Knit Each Square: Step-by-Step

Let us walk through the process of knitting one square. You will repeat these same steps for every square in your blanket.

Step 1: Cast on. Using the long-tail cast on method (which produces a neat, elastic edge), cast on the appropriate number of stitches for your gauge. For the sake of this tutorial, let us say your gauge gives you 27 stitches for a 6-inch square.

Step 2: Knit every row. Work in garter stitch (knit every row) until your square is as long as it is wide. Check by folding the square diagonally — if the corners meet up and the piece forms a perfect triangle, your square is done. You can also measure: once you have approximately 6 inches of fabric from the cast-on edge, you are ready to bind off.

Step 3: Bind off. Bind off loosely in pattern (knitting each stitch as you would normally before passing the previous stitch over). A tight bind-off can pucker the edge and cause problems during seaming. If you tend to bind off tightly, try going up one needle size for the bind-off row.

Step 4: Weave in your ends. Leave a tail of at least 6 inches when you cast on and bind off, then use your tapestry needle to weave these ends in securely along the edge of the square. Weave in one direction for a few stitches, then back in the other direction, to lock the end in place.

Step 5: Block each square. This is the step most knitters skip, and it is the step that makes the biggest difference. Wet each finished square, squeeze out excess water without wringing, lay it flat on your blocking mat, and use T-pins to stretch and pin it to exactly 6 by 6 inches. Let it dry completely before removing the pins. Blocked squares are dramatically easier to seam than unblocked ones.

Planning Your Checkered Rainbow Layout

Now comes the fun part — deciding how your squares will be arranged. A checkered rainbow pattern works by alternating each rainbow color with your neutral, so that no two rainbow squares sit directly next to each other. The result is a grid of color separated by white (or whichever neutral you have chosen), which keeps the design from feeling overwhelming while still delivering a vibrant, joyful effect.

For a blanket that is 8 squares wide and 10 squares tall, you will need 80 squares total. In a true alternating check pattern, 40 squares will be your neutral and the remaining 40 will be divided among your six rainbow colors. That gives you about six to seven squares of each color (you can adjust slightly depending on how many colors you are using and how much of each you want to feature).

Lay all your finished, blocked squares out on the floor. Arrange the neutrals in a checkerboard pattern — one on, one off — and then place your rainbow colors in the remaining spots. Experiment with different arrangements: you might want your colors to graduate from red on one end to violet on the other in diagonal stripes, or you might prefer a more random, scattered effect. Take photos of each arrangement you like before disassembling it, so you have a record to refer back to.

Pro tip: Numbering your squares with small sticky notes or locking stitch markers once you have settled on a layout can save you enormous confusion when it comes time to seam. Lay them in order and number them from left to right, top to bottom (1 through 80 for an 8×10 blanket).

Joining Your Squares: The Mattress Stitch Method

There are several ways to join knitted squares, including crocheting them together, the three-needle bind-off, and various sewn seams. For a checkered rainbow blanket, the mattress stitch seam is the most professional-looking option because it is virtually invisible on the right side of the fabric.

To work the mattress stitch on garter stitch squares, lay two squares side by side with their right sides facing up. Thread a long length of your neutral-colored yarn onto a tapestry needle. Insert the needle under the bar between the first and second stitch along the edge of one square, then under the corresponding bar on the other square. Pull the yarn through gently. Continue alternating from side to side, picking up one bar on each square, for the entire length of the seam. Every few inches, pull the seaming yarn snug — you will see the two edges draw together and, with practice, become nearly invisible.

Join your squares in rows first, then seam those rows together. This two-step approach is generally easier to manage than joining squares one at a time across the entire blanket.

Adding a Border

A border transforms a collection of joined squares into a finished blanket. For a checkered rainbow project, a simple garter stitch border in your neutral color is elegant and cohesive. Pick up stitches evenly around the entire perimeter of the blanket, work several rows of garter stitch, and bind off. The exact number of rows you work is up to you — three to five rows produces a narrow, delicate border, while eight to ten rows creates something more substantial and cozy-looking.

Pro tip: When picking up stitches along the sides of a garter stitch blanket, pick up approximately three stitches for every four rows. This ratio prevents the border from pulling in (too few stitches) or ruffling outward (too many stitches).

When you reach corners, work a yarn over or a knit-front-and-back increase on each side of the corner stitch on every right-side row. This allows the border to turn the corner neatly without puckering or pulling.

Final Blocking and Care

Once your border is complete, give the entire blanket one final, thorough blocking. Soak it in cool water for twenty minutes, squeeze out as much water as possible, and lay it flat on a clean surface. Smooth it out to your desired dimensions, pin the edges, and allow it to dry fully. This final blocking evens out any inconsistencies in the seams and gives the whole blanket a unified, intentional look.

For ongoing care, most worsted-weight wool or wool-blend yarns can be hand-washed in cool water and laid flat to dry. Acrylic yarns are typically machine washable on a gentle cycle. Always check your yarn label for specific care instructions and make a small note to tuck inside any gift packaging if you are making this blanket for someone else — it is a small courtesy that experienced fiber artists deeply appreciate receiving.

Troubleshooting Common Problems

Even experienced knitters run into snags with this type of project. If your squares are not all the same size after blocking, check whether your tension changed between square batches. Try adjusting needle size slightly, or be mindful of knitting more loosely or more tightly to compensate. If your seams are puckering, try using a lighter touch when pulling your seaming yarn — the mattress stitch should be snug but not tight. If your border is ruffling, pull out the picked-up stitches and start over, picking up fewer stitches per inch.

Remember that knitting is a forgiving craft. A blanket made with love and effort is a beautiful object regardless of minor imperfections, and most people who receive or admire your work will never notice the tiny things you agonize over.

Final Thoughts

A checkered rainbow knit squares blanket is more than just a craft project. It is a long, meditative journey made up of dozens of small, satisfying steps. Every square you finish is a tiny victory. Every seam you sew brings the whole picture a little more into focus. And when you finally spread the finished blanket out and see all those colors laid out in their cheerful, orderly checks, you will feel the particular pride that only comes from making something beautiful with your own hands.

Take your time, enjoy the process, and do not skip the blocking. Your future self — the one curled up under a warm, colorful blanket on a cold evening — will thank you.