The thermal stitch is one of the warmest crochet stitches! Aptly named, this stitch makes a beautifully thick and sturdy fabric—perfect for projects that need added weight and warmth.
Some of my favorite projects to make with the thermal stitch are potholders, bags, and baskets. The thermal stitch is perfect for anything that needs to stand up to wear and tear. For instance, washcloths would make a great thermal stitch project.
This stitch is made entirely of single crochet! Instead of working into both loops of each stitch on your current row, you’ll insert your crochet hook through the back loop of your current row as well as the open loop from the row below it. While it sounds confusing, the thermal stitch is really quite simple once you’ve seen it done. Keep reading to learn the thermal stitch!
The Thermal Stitch
*Note: In this tutorial I used a worsted weight yarn and size 5mm (US H) hook. Feel free to play around with your hook size and yarn to achieve your desired results! I also use US crochet terms throughout.
- Make a slip knot and chain any number of chains by yarning over and pulling through the loop on your hook. There is no multiple required for this stitch, so chain your desired length.
- Starting in the second chain from the hook, single crochet using the back loop of the chain only. Continue to single crochet in the back loop only until you reach the end of the row. Chain one and turn your work.
- Insert your hook through both the back loop of the current row and the open loop from your chain (the loop you did not work into). Yarn over and pull through two loops on your hook. Then yarn over again and pull through the remaining loops to complete your first single crochet thermal stitch. Continue this until the end of the row. Chain one and turn.
- Again using only the back loop of the current row and the unworked loop from the row below, single crochet across. That’s it! Continue to crochet rows of thermal stitches until the piece is as tall as you’d like it to be. When you are ready to finish your piece, move on to step five.
- Chain one and turn. For your last row, you will be inserting your hook through both loops of the current row as well as the open loop from the previous row (three loops total). Then, you may single crochet or slip stitch across to finish.
That’s it! You’ve learned the thermal stitch—simple, right?
As with any crochet stitch, you can use the thermal stitch to make just about anything. Because the thermal stitch creates a thick fabric, I would recommend against using it for wearable items. Again, potholders are a popular project for this stitch, as are baskets.
Since this stitch is worked into both the current row and the row below, it takes a while to build up height. Plus, each row is very short. This is something to note for larger projects, like blankets, that already take a long time to complete.
How to Count Rows with the Thermal Stitch
Unlike a normal single crochet stitch, the thermal stitch is worked in two different rows. This can make it difficult to count your rows. My advice would be to leave your starting tail loose (the tail of your slip knot) and use that as a guide.
For instance, if the tail is on the left of your piece, you are currently working into an odd numbered row. The converse is true. If the tail is on your right, you are working into an even numbered row.
To count your rows of thermal stitch, I find it easiest to position your piece so that the starting tail is on the left. The first row you see is actually row two. Now, you can count each upside down “v” (each stitch) as two rows. Pictured below I have 13 rows.
At the top, I counted just one row because there is no visible “v.” This indicates that there is just one row present.
Variations on the Thermal Stitch
You can also work the thermal stitch with different crochet stitches to get a different pattern and weight. Some popular variations use the half-double crochet stitch and the double crochet stitch.
For these variations you follow the same procedure as explained above, except you work a different kind of stitch into the current back loop of your row and the open loop below. Pictured below are the half-double crochet thermal stitch and the double crochet thermal stitch.
The half-double crochet thermal stitch is slightly thicker than the single crochet thermal stitch, as is the double crochet thermal stitch.
Some Simple Projects for Practice
- Extra Thick Crochet Potholder
Potholders need to be thick to protect your hand from the head of a baking tray or pot. The thermal stitch is arguably the best stitch to make a crochet potholder. This pattern uses a double-crochet thermal stitch, but can easily be modified for the single crochet version.
Click here for the free pattern.
- Thermal Stitch Bath Mat
This bath mat pattern employs the thermal stitch to make a wonderfully thick and squishy mat, ideal for stepping on after the show. Chenille-style blanket yarn is recommended for this project to make the mat absorbent and machine washable.
Click here for the free pattern.
- Crossbody Strap
The thermal stitch creates a nice and sturdy strap for crochet bags! This pattern walks you through the process of adding a strap to your favorite crochet bags and even explains how to crochet onto a D ring or split key ring for added durability. The thermal stitch, like any crochet stitch, will stretch a little bit, but it is a tried and true method for making robust bag straps.
Click here for the free pattern