Summer Snowflake – Free HST Quilt Pattern with Easy Layout Mat


Sew a beautiful throw quilt with half square triangles! My Summer Snowflake free HST quilt pattern comes with a layout mat to make it super easy to keep track of your half square triangles.

I love half square triangles, known as HST’s in the quilting world. Making and sewing them together is easy and repetitive, it’s my my ‘quilt therapy.’ And there are lots of different ways to sew HST’s. Even though this quilt is sewn with small 2 1/2” HST’s, keeping them organized and sewing them together properly is easy with the free layout mat I designed for this quilt.

This blog post has been converted to an optional PDF that’s optimized for printing. Find it here. The blog post below contains everything you need including all the instructions and the free printable layout mat. The instructions are totally free to read, print, and sew! Just hit CTRL +P on your computer to print. The PDF download for $3 is totally optional. Did you know you can get ALL the Optimized for Printing PDF files organized in a library for you to access anytime you want? Check it out.

This quilt design uses 512 scrappy half square triangles. Half of them are gray or another neutral color. The other half are made with brightly colored fabric. My background fabric is a light cream color.

If you love to use your Accuquilt fabric cutter like I do, I’ll share the optional cutting die numbers to make this pattern Accuquilt friendly. Using an Accuquilt is optional, but I love it! See all my Accuquilt friendly quilts.

This quilt pattern is included in my roundup of all my favorite free HST quilt patterns. Don’t miss it!

Click the link above to download the free printable layout mat that makes sewing the Summer Snowflake quilt easier than any other half square triangle quilt.

I made a video to demonstrate how to use it. A shortened version of the video will play automatically on this page. Visit my YouTube channel to see the full Summer Snowflake Layout Mat Instruction video.

You can sew the entire Summer Snowflake quilt from scraps too! I gathered together scrap fabric in 4 different bright colors, plus a whole lot of leftover gray fabric. The gray snowflakes recede into the background of your quilt to make the brightly colored ones really pop!

Summer Snowflake Free HST Quilt Pattern

Finished size: 70” x 70”

You will need:

  • 1/4 yard (total) bright pink fabrics
  • 1/4 yard (total) dark blue fabrics
  • 1/4 yard (total) bright yellow fabrics
  • 1/4 yard (total) bright orange fabrics)
  • 1/2 yard (total) light and medium gray fabrics
  • 4 3/4 yards solid light cream fabric for the background
  • 1/2 yard fabric for the binding*
  • a 75” x 75” or larger piece of quilt batting
  • 4 1/2 yards of fabric for the quilt backing, or enough for a 75” x 75” backing piece

*Note if your binding fabric is narrower than 44” wide, you may need a little extra fabric for binding.

Make 512 Scrappy Half Square Triangles

To make the Summer Snowflake Quilt, you will need:

  • 64 bright pink/light cream HSTs
  • 64 dark blue/light cream HSTs
  • 64 bright yellow/light cream HSTs
  • 64 bright orange/light cream HSTs
  • 256 gray/light cream HSTs

All of the half square triangles should measure 2 1/2” before you sew them into the quilt and 2” finished.

If you have an Accuquilt cutter, you can quickly sew the half square triangles together without using the shortcut method below. The following dies will work with this quilt pattern:

  • 2” finished HST 55063
  • 2” finished square 55059
  • 3 1/2” strip die 55032 (for the borders)

Ways to Sew HST’s (half square triangles)

There are lots of different ways to sew half square triangles. I encourage you to try lots of different ways and find your favorite method!

HST Method 1

When I was sewing the half square triangles for this quilt, I used a printable paper template to make 8 perfect HST’s at one time using just two 6” squares of fabric. Then later I sat and watched TV while I removed the paper. It was relaxing and rewarding at the same time!

Watch me demonstrate sewing with HST paper on YouTube and find out where I found paper for it at the dollar store!

Download the free HST Paper Template from this blog post.

You will need to cut:

  • 8 bright pink squares 6” x 6”
  • 8 dark blue squares 6” x 6”
  • 8 bright yellow squares 6” x 6”
  • 8 bright orange squares 6” x 6”
  • 32 gray squares 6” x 6”
  • 64 background fabric squares 6” x 6”

For the rest of the quilt, you will also need to cut the following pieces from background fabric:

  • 512 squares 2 1/2” x 2 1/2”
  • 2 border strips 3 1/2” x 64 1/2” (you will need to to piece these together)*
  • 2 border strips 3 1/2” x 70 1/2” (you will need to piece these together too)*

*For a smoother quilt top, be a quilt pirate and use these measurements as guidelines. See How to Add Quilt Borders the Correct Way.

Then use the paper piecing method to make the 512 half square triangle units.

HST Method 2

If you don’t want to use a paper template to make your half square triangles, you can still make them quickly and easily. The shortcut method that I share in this blog post makes two HST’s at one time and also has very little waste.

For the two-at-a-time HST method, cut:

  • 32 bright pink squares 3” x 3”
  • 32 dark blue squares 3” x 3”
  • 32 bright yellow squares 3” x 3”
  • 32 bright orange squares 3” x 3”
  • 128 gray squares 3” x 3”
  • 256 background fabric squares 3” x 3”

For the rest of the quilt, you will also need to cut the following pieces from background fabric:

  • 512 squares 2 1/2” x 2 1/2”
  • 2 border strips 3 1/2” x 64 1/2” (you will need to piece these together)
  • 2 border strips 3 1/2” x 70 1/2” (you will need to piece these together too)

Sew all 512 half square triangles using the 2 at a time technique demonstrated here. Press each one open and trim to 2 1/2’’ square.

Tip: BlocLoc HST Rulers are fun to use and make trimming HSTs a breeze.

Those are my two favorite shortcut methods for making half square triangles. If you have a different favorite HST technique, be sure to tell us what it is in the comments.

Use the HST Layout Mat to Make 1/4 of a Summer Snowflake Quilt Block

1. Place the downloadable layout mat next to your sewing machine along with a pile of 8 background fabric 2 1/2” squares, 4 gray HST’s, and 4 HST’s of one bright color.

2. Place the brightly colored HST’s in the spots on the mat, making sure that the orientation of the half square triangles matches the orientation of the triangles on the mat.

3. Place the gray HST’s in the gray spots on the mat and fill in all of the empty spots with background fabric squares.

4. Chain piece all of the quilt pieces on the mat. Start by placing the first two units in columns 1 and 2 together and sewing with a 1/4” seam allowance.

5. Without cutting the thread, place the next two units together in columns 1 and 2 together and sew with a 1/4” seam allowance.

Continue sewing together the rest of the pieces in the first two columns.

6. Now sew together the first two pieces in columns 3 and 4 with a 1/4” seam allowance.

7. Continue sewing the pieces in columns 3 and 4 together until all of the pieces are sewn.

8. Place the long string of chain pieced units on your pressing board and flip every other unit up as seen below.

This technique ensures that your seams are pressed in opposite directions, which makes nesting the seams easy later.

Note: I cut my long chain in two pieces before pressing so you would be able to see all of it in the image above and in the video.

9. Press each piece open.

10. Bring back the layout mat and place the quilt units on it again, matching up the brightly colored and gray triangles.

Cut apart the quilt pieces, if you haven’t already.

11. Chain piece these units together in pairs to make 4 small rows.

12. Press the small rows using the flip technique shown above so that you can nest these seams too.

13. Then place the 4 rows back on the mat to ensure that they are sewn together in the correct order and orientation.

14. Place row 1 on top of row 2 and stitch with a 1/4” seam allowance.

15. Repeat with rows 3 and 4.

16. Place the two units back on the mat in the right places.

17. Sew the last two pieces together with a 1/4” seam allowance.

18. Press all of the seams toward the top of the piece.

Use 4 Pieces to Make One Quilt Block

1. Use HST units and the mat 3 more times to make 4 pieces that are the same colorway.

Rotate the pieces to make the snowflake shape shown that forms a pinwheel in the middle.

2. Sew the 4 pieces together and press flat.

Repeat to make 16 Summer Snowflake blocks, 4 of each colorway.

Assemble the Quilt Top

1. Use a quilt design wall or large surface to arrange the 16 quilt blocks as shown.

2. Sew the blocks together to make 4 rows.

3. Sew the 4 rows together.

4. Sew the 3 1/2” x 64 1/2” border strips to the sides of the quilt top.

5. Sew the 3 1/2” x 70 1/2” border strips to the top and bottom of the quilt top.

Finishing the Summer Snowflake Quilt

1. Cut the backing fabric in half and sew it together to make a piece big enough for the back of the quilt (at least 75” x 75”).

2. Sandwich the quilt top, batting, and backing together and baste. For a quilt this large, I perfer pin basting with quilter’s safety pins.

3. Quilt the quilt top as desired.

4. Cut 7 strips of binding 2 1/2’’ x width-of-fabric (or as desired) and sew them together using diagonal seams. Bind the quilt using your preferred method. See how I mind my quilts by machine here.

Note: If your fabric is narrower than 44” wide, you may need to cut 8 binding strips.

I love to see the quilts and other things you sew with my tutorials! If you make a quilt using this free HST quilt pattern, please post a picture to Instagram and tag me @sewcanshe!

Happy Quiltmaking!

P.S. If you love this half square triangle quilt pattern, I think you’ll love these others too:


Disclosure: some of my posts contain affiliate links. If you purchase something through one of those links I may receive a small commission, so thank you for supporting SewCanShe when you shop! All of the opinions are my own and I only suggest products that I actually use. 🙂