Many triangular lace shawls – including my own designs – begin at the center back, with a small number of stitches, and then grow in ever-lengthening rows, which form 2 triangles, separated by a center stitch. 
To begin this type of shawl, a garter-tab cast-on is recommended, as this technique creates a small rectangle of garter stitch, which blends seamlessly with the garter stitch edging which forms the top horizontal line of the shawl. It is a bit more work than just casting on stitches normally, but the results are worth the extra effort.
This tutorial will illustrate how to execute the following instructions to form a garter-tab cast-on:
CO 3 sts. provisionally. Knit 14 rows. Knit 15th row, then pick up 7 stitches along the border of the small garter stitch rectangle you have just knit, then undo the provisional cast-on, put the 3 cast-on sts on a needle, and knit them (13 sts total).
So, first you will use a provisional crochet-chain cast to cast on 3 stitches. A provisional cast-on is any type of cast-on which creates live loops or cast-on stitches that you can later knit. The crochet chain provisional cast-on is just one of many options. To work it:

3. Use the crochet hook to pull the yarn which was wound around it through the knot, creating a new loop. Repeat steps 2 and 3, wrapping, and then pulling the yarn through the loop below to create a chain of loops. You should chain a few more loops than the number of stitches you want to cast-on.

7. Wrap working yarn around the needle, as though you were knitting a stitch. Then, just as though you were knitting a stitch, pull a loop back through the crochet chain, creating a stitch.
You have successfully cast-on 3 stitches provisionally!! Now proceed to creating the garter tab:

9. Knit 15 rows (or the number called for in your pattern). This creates a tiny rectangle of garter stitch, which is your 'garter tab'.

10. To pick up stitches along the edge of the garter tab, insert the tip of the needle through the work, 1 stitch in from the edge, wrap the yarn around the needle, and pull a loop through the work, just as though you were knitting a stitch. Repeat this step until you have picked up the required number of stitches (in this case, 7).

On the needles, I now have the 3 stitches I started with, plus 7 stitches that I picked up along the edge of the garter tab.

11. Now undo the crochet chain by pulling the end of the yarn through the last loop which had secured it, and tugging gently on the end to unzip the crochet chain.
Voila!! You now have cast-on a total of 13 stitches! This is your first RS (Right Side) row, so you will work a WS (Wrong Side) row, and then begin knitting your lace shawl from the pattern charts! Soon it will begin to look like a tiny triangle, and it will almost certainly be love at first sight!










August 2, 2009 at 1:52 pm
These instructions are very clear, but — using this method — will I still get the points such as on the Entomology shawl or your Photosynthesis shawl?
August 2, 2009 at 2:29 pm
Nancy – The Garter Tab Cast-on method is how you start your shawl – when you get to the very end of the shawl, and work the lace edging and bind-off, you are working the part of the shawl that forms the scalloped edging. So the little garter tab is almost invisible at the end, because it is in the center back of the piece of lace. It is the last few rows (at the bottom edge), and the way that you block your shawl which determine how the edge will look.
So Yes – you will still get the scalloped edge with points as you see on the Etymology or Photosynthesis shawls!
Cheers – Emily
August 3, 2009 at 12:16 pm
[...] to see the colors she picked out for our Ulmuses. Hopefully, between the advice of Meezermeowmy, Damp City Knit’s Garter Tab How-To and a few other resources we will manage the pattern without too much [...]
August 7, 2009 at 10:25 am
Great instructions! thanks!
September 5, 2009 at 1:38 am
Oh, bless you for this! I’ve just started a triangular shawl which starts with a provisional CO and the garter stitch tab (nice term!) but doesn’t clearly identify taking the CO out to get the last three stitches. I thought I knew what to do but your post clarified it beautifully, thanks so much!
November 9, 2009 at 3:00 am
These instructions are extremely helpful! Thank you for making this tutorial.
I’m wondering if you can help me with something else. I’m working on the Swallowtail shawl http://www.evelynclarkdesigns.com/pdf/Swallowtail.pdf and I have finished everything except the border, because I can not for the life of me, figure out how to start it. Could you maybe explain this or point in the direction to a tutorial? It would be greatly appreciated.
November 14, 2009 at 12:06 am
Oh many thanks! I have finally just understood!!
December 1, 2009 at 6:39 am
Thank you so much for the clear explanations and illustrations!
I am an absolute beginner of lace shawl knitting and have a hard time understanding how to begin my first shawl by reading the instructions on the pattern…
January 22, 2010 at 5:17 pm
This is just wonderful! I’m starting my first lace shawl and was so sure I was doing things wrong. Thanks for a great tutorial with clear pictures AND written instructions.
January 27, 2010 at 1:33 am
[...] I’m aiming to finish a knitting project every month since I have altogether way too many WIPs that I want to have finished tout de suite! This month I dug out my Aeolian shawl (here is the original pattern) which has been sadly neglected, 15 rows from finishing, since last summer. The thing with this kind of shawl is it is a triangle shape, with the point facing down. The knitting starts in the middle of the top long edge, with each row starting from the long edge, moving towards the middle to form one side of the triangle, then from the point returning to the edge again to form the third side of the triangle. Here’s a great diagram I found with a photo tutorial. [...]
May 21, 2010 at 9:27 am
This is a wonderful cast-on. Thank you for a photo-riffic tutorial!
June 18, 2010 at 9:55 pm
Thank you-this is so clear with great photos!
August 14, 2010 at 5:30 am
Very helpful!!!
October 4, 2010 at 2:34 pm
This tutorial makes sense and since I am a visual learner, I will save this and use it when I start my shawl.
TY…Abbie
October 11, 2010 at 12:52 pm
Beautifully illustrated garter stitch tab!! Thank-you!
As a visual learner, I struggled repeatedly with the written instructions for the garter stitch tab. And then, I found your instructions and photographs. And voila,… I am finally able to get my lace project started.
Again,… very nicely done!!
Corinne
January 8, 2011 at 5:50 am
Thanks so much for this great tutorial! The pictures are very clear and I am now ready to go!
January 26, 2011 at 9:10 am
[...] by making a garter stitch rectangle. For more on starting a triangular shawl have a look at Damp City Knits post on the Garter Tab Cast on. This leaves you with 11 stitches (3 on each side and 5 on the long [...]
January 28, 2011 at 6:12 am
Thanks for the help. I am starting the pattern from Knitty of Citron:)
January 30, 2011 at 8:59 pm
[...] Garter stitch tab, a “how to” courtesy of Damp City Knits blog. [...]
March 17, 2011 at 4:23 pm
Thanks for the pictures and explaination. I got to “see it” to understand. I appreciate the time you put into this.
April 19, 2011 at 10:05 am
Thank you so much for this tutorial!!! I tried several times to figure it out from the directions but failed miserably. I really needed the pictures to describe it. Thanks again!
May 18, 2011 at 9:49 am
I wish I had found this tutorial when I made my Ishbel. I must have ripped out 20 times. I had to cut off the end of my yarn because it was so frayed. Thanks much for a wonderful, easy to follow tutorial.
May 24, 2011 at 7:10 am
Dear Emily,
Thank you so much. This is just what I was looking for. I knew how to begin a triangular shape without the tab, and wanted a more complete way to do it.
Isn’t it lovely that all of your good cheerful work is being found and used almost two years later. May there be many more. Thank you, again.
July 23, 2011 at 7:44 pm
Thank you! I just started the Daybreak shawl and ripped it out because I knew I’d done something wrong. I’m so glad I found this!
August 29, 2011 at 6:48 am
[...] Garter stitch tab, a “how to” courtesy of Damp City Knits blog. [...]
September 20, 2011 at 2:47 pm
Thank you so much for this tutorial!!!
Muchísimas gracias, es perfecto para el chal que quiero hacer.
September 23, 2011 at 2:32 pm
Yours is the first explanation of provisional cast-on that has made sense to me. Thank you so much for this valuable tutorial. I’m now looking forward to trying several patterns I once was afraid to attempt.
October 10, 2011 at 2:50 am
Oh thanks! so much. I have finally just understood!!
Muchas gracias!
January 20, 2012 at 1:46 am
Swami Vivekanand…
[...]Garter Tab Cast-On – How to start a triangular lace shawl « damp city knits :[...]…
February 19, 2012 at 12:33 am
[...] wiederstehen? Wo doch der Frühling fast vor der Tür steht! Nachdem ich verstanden habe, wie ein Garter Tab Cast On funktioniert, stricke ich mich tapfer durch immer mehr werdende Links-Rechts-Maschen und freue mich [...]
June 3, 2012 at 7:59 pm
thank you so much for clear instructions with great pictures to back up the how to
Bubs H
August 15, 2012 at 5:55 pm
These are the clearest instruction i’ve come across! I was just about to completely give up on knitting and then I found your instructions…..thank you so much!!!!
November 7, 2012 at 11:36 pm
Sono entusiasta di questo particolare cast-on !!!! Grazie per essere stata cosi’ chiara .Magari trovassi qualcuno che mi spiegasse cosi’ chiaramente le SHORT-ROWS!!!!!!!
<3
November 22, 2012 at 1:40 am
Reblogged this on Rahymah Handworks.
April 12, 2013 at 2:20 pm
This blog was… how do you say it? Relevant!! Finally I have found something which helped me.
Cheers!
April 13, 2013 at 8:10 am
Thanks! We do our best