Bring on the Reinforcements

Real "sock" yarn is special. Not all fingering-weight yarn is suitable for socks, straight off the skein. The best long-lasting "sock" yarn has the following characteristics:

• high twist
• multiple (usually 4) plies
• thin (350-450 m/100g)
• contains nylon (preferably at least 20%)
• not "merino"

If you get yarn that you want to use for socks that is missing one or more of these characteristics, don't despair! You can still use it if you take a few simple precautions.

The first precaution is to reinforce your knitting at the heels and toes (this are the high-abrasion zones, where no-nylon merino gives up the ghost pretty quickly). This can be done in a couple of ways:

1. use reinforcement thread. This stuff is made by a number of different yarn companies including Regia, Lang, Scholler & Stahl, and Fortissima. I know it's available from several online stores (like here, or here, or here) and my LYS carries a limited number of colours. It comes on little carboard skeins and looks totally retro:

[reinforcement or darning thread]

To use this stuff, hold it together with your regular yarn and just knit as normal. The heel/toe will be a bit thicker and stiffer, but it will last a lot longer. The fabric will also take on a slightly different colour because you will see the reinforcement thread. You can use "wooly nylon" serger thread or laceweight yarn with nylon in it as reinforcement thread also, if you have some at hand (it's typically more expensive than reinforcement yarn but you get giant amounts of it instead of only 5g). Don't use sewing thread (which is polyester), as this will actually do more damage than good (the sewing thread is not as elastic as the yarn and ends up cutting into it over time).

2. Use the same reinforcement thread OR some of your yarn, and duplicate-stitch over the area where you know you are going to get holes. If this is a big area (like a heel) this is a big job and a huge pain. I do it over my big toenail area, which is where I invariably get holes. That's not such a large spot so I'm OK with it. Alternatively - and less work - "predarn" on the inside of your sock by running the darning yarn up and down through the back loops of the reverse stockinette. This is much less work and still gives you added protection.

3. You can use a slip-stitch pattern on those areas prone to wear. This is standard for flap-heels and many patterns will guide you through this. Typically though the slip-stitch pattern is not carried through to the bottom of the heel (only on the back) and it isn't in the toe area either. But there is no reason why you can't put it there! It's kind of a pain to do increases and decreases with slip-stitch patterns so it's easiest to pick a rectangular area and just do it within those boundaries. Slip-stitch patterns will suck in the fabric width-wise, so swatch first to see if you need to add a few extra stitches to offset this. Cat Bordhi's "sweet tomato heel" has a slip-stitch version that offers reinforcement on the bottom of the heel.  You can try the same idea on my "sweet tomato hybrid".

The second precaution has to do with laundering socks.  Non-sock yarns - especially those made of merino or other luxury fiber blends (silk, alpaca, cashmere...) - tend to be less resistant to the frequent washing that socks are subjected to. The yarn will start to sag and pill over time. You can extend the life of such socks by hand-washing them, and of course never, ever throwing them into the dryer. Other precautions include turning them inside out before washing - you'll abrade the inside rather than the outside this way. If you can stand the idea, wear your socks longer than 1 day. If you can wear them for 2 days, for instance, you will wash them 1/2 as much, so it's a big reduction in the amount of abuse they get from laundering.

By following these precautions, I've used non-sock-yarn with success - Tosh Merino Light, a single-ply, no-nylon, merino fingering weight yarn, is one of the yarns that has given me surprisingly good results.