When I swatched the thermal stitch for a new crochet sock design recently, I made a discovery: if you change colours and turn after each round you create a fabric that is reversible!
Before I jump into my Thermal single crochet tutorial, a brief pause.
With all crochet colourwork, a major issue is having the yarn on the correct side when we come back to it. This tip helps with this!
(1) Changing colours in thermal single crochet to create a reversible fabric
In my Hestia crochet ankle socks, I use the abreviation bytf (bring yarn to front) at the end of my rounds:
Ch 1, tsc in each st around, bytf, join with sl st in 1st st, turn.
We do this when changing colours so the dropped colour is on the correct side when we come back to it later! Simply drop the current colour in front of the work after completing your last stitch, insert the hook into the 1st stitch, yarn over with the new colour, complete the slip stitch and turn.
Now onto our main course.
(2) How to: Thermal single crochet
Thermal single crochet gets its warmth and thickness from working each row or round twice – this also makes it a fairly time consuming stitch!
Thermal single crochet is worked just like single crochet – what changes is where we insert out hook.
Thermal single crochet (tsc): Insert hook in the back loop of the current stitch and in the unworked loop of the stitch two rounds below, yarn over, pull up a loop, yarn over, pull through two loops on hook.
These two loops are identified in the picture on the left:
Note: The very first row or round of a project is worked into the back bumps of the chains, which frees up a loop to crochet the thermal single crochet stitches into next.
(3) How to: Thermal single crochet… decreases and increases
The decrease in thermal single crochet is pretty straightforward: it will be done only once in your two-row or round repeat, and it will be done as usual: by starting a thermal single crochet in each of two consecutive stitches and closing them together.
In the next of two rows or rounds there is nothing special to do when you reach the decrease.
The increase is a little different.
In the first row or round of the increase, you will increase as usual: by making 2 thermal single crochet stitches in the same space (pictured left).
Thermal single crochet increase – first round (tsc-inc-fr): (Insert hook in back loop of current stitch and in unworked loop of stitch two rounds below, yarn over, pull up a loop, yarn over, pull through two loops on hook) twice.
It’s the second round that’s a little bit different.
You’ll make the 1st thermal single crochet as established, and the 2nd one by inserting your hook into the back loop of the next stitch and into the SAME unworked loop as the previous tsc (pictured right).
Thermal single crochet increase – next round (tsc-inc-nr): Insert hook in back loop of current stitch and in unworked loop of stitch two rounds below, yarn over, pull up a loop, yarn over, pull through two loops on hook, insert hook in back loop of next stitch and in SAME unworked loop as previous tsc, yarn over, pull up a loop, yarn over, pull through two loops on hook.
If you use this stitch for crochet socks, make sure to confirm your gauge for both colours used. It’s possible you’ll need to change hooks when you change colours!
After you’ve master the thermal single crochet, you may want to tackle my Hestia crochet ankle socks.