Longtail Cast On

Before you start, you need to make a few purchases. Don't go overboard and buy a bunch of supplies, you have time for that later! Right now, you need one set of needles and some yarn.

Needles

The material that the needles are made from isn't that important. They can be made from aluminum, wood, bamboo or acrylic. If forced to make a suggestion for a beginner, I would recommend aluminum. They are durable, fairly inexpensive, and readily available at large discount and craft stores. They can be either straight or circular.

Straight needles come in 14” and 10” lengths, are solid in construction and…straight. :o) Circular needles are 2 slightly shorter knitting needles that are permanently attached to one another by a flexible cable. Their purpose is to allow you to knit a tubular piece so that you can avoid sewing seams, but they can also be used in flat knitting. They are especially helpful when knitting a large flat item like an afghan, that has too many stitches to fit on a straight needle. I never use straight needles anymore, because it’s more cost efficient to have one set of needles that can be used in either situation. There are circular needles that have interchangeable cables and are purchased in sets. I highly recommend them but not until you know that you’ll be a knitter for life. If circular needles are your choice, just focus on a regular set of circular needles with a fixed cable at this time.

 I recommend 10" straight needles or a circular needle that is at least 24" in length. Ideally for a beginner the needles would be a size 7, 8 or 9, however if you already have some knitting needles in your possession just use what you have in any material, in the closest indicated lengths and sizes. This is not the time to get obsessive.

Yarn

For learning, you can't go wrong with an inexpensive 100% acrylic yarn in a Medium (4) weight, otherwise known as worsted weight. Standard acrylic yarn may not be fashionable but there is no reason at this point to spend a lot of money on yarn. I am all about saving money! I am sure that a lot of folks will disagree with me about the acrylic yarn and you may disagree as well. That's fine, buy whatever you like but my recommendation is still 100% acrylic for learning but you should definitely stick with the Medium (4) weight. Again, you can find it in discount stores as well as in craft stores.

Getting Ready to Cast On
After you watch the video below, you will have a better understanding of the following information.

To begin the Longtail Cast On, you need to place your slip knot well down your yarn strand and away from the loose, unattached end. There are several methods for determining how far you should go, but unfortunately I have never had much success with any of them. Basically, the more stitches you need to cast on the farther into the yarn you should place your slip knot. The most logical method is to cast on 20 stitches, remove your needle, unravel the stitches and measure from the unattached end to the slip knot and write this number down. Then take the number of stitches that you are required to cast on, divide by 20 (the number you cast on for your test). Take the resulting number and multiply by the number that you wrote down. This is the minimum number of inches that you should place your slip knot from the unattached end.

Example
I cast on 20 stitches and measured to the slip knot and got 30”. Make sure to add enough extra so that you’ll have a nice yarn tail left over after the cast on. It will be woven in and hidden later. I like to have at least 6-8”. It is preferable to have more than you need than to have a tiny end to hide that will probably pop out at the first washing.

The cast on for my project is 82.     
82 project cast on ¸ 20 test cast on = 4.1     4.1 x 30” measurement from test = 123”
So I will place my slip knot at least 123” from the end of the yarn.

Keep practicing until you get nice even consistent loops along the bottom edge. I have a bit of information that won't mean a great deal to you right now, but the first row knit after using the Longtail Cast On is a wrong side row and the second row is a right side row. You won't find this to be the case on the majority of cast ons that you work. It means that depending on the pattern, you may have to knit an extra row when using this cast on. Now, let’s knit y’all!

Alternative cast on to the Longtail Cast On