If you have knitted a sweater, tried it on, and it is too short, there is a relatively easy way to fix it. Of course, if the sweater is knitted top down, you can just rip it back to the ribbing and continue down. If however, you have knitted bottom up (which is the most common style of sweater construction, all is not lost.
I knitted this top, and was quite despondent when I tried it on. It was too short, and the waist shaping was in the wrong place, creating an unfortunately ear flapping effect above my hips. I am sure that Elizabeth Zimmermann was the source of this fix, but can’t find the reference for the life of me, (maybe it was the DVD Knitting Workshop
I chose a place on the side, just above where the top had gone wrong. If I had not had the double trouble of the dodgy waist shaping and the length, I would have chosen a spot just above the ribbing. Then I used a tapestry needle to undo the row that I had just snipped. I highly recommend doing this on a stable table, with good light. Unpicking the 200ish stitches took me about 20 minutes and was easy for someone who has had to unpick a lot of machine sewing.
Once the two pieces were completely separated, I joined my yarn to the tail from the top part of the sweater, and put the stitches back onto a circular needle which was one size smaller than recommended in the pattern. Using a smaller needle makes the job of picking up the stitches much easier. I then knitted down, following the pattern from the waist in reverse (increasing where it specified decreases), after adding extra length to the waist. Once I finished the ribbing, I cast off loosely.
While I was knitting down, I was quite worried by the appearance of the knitted on portion, compared to the original top.
The line across the top is the row where I picked up the stitches and knitted down. The difference in appearance was even more apparent on the purl side.
If the difference appears to be startling, do not worry! So long as you are using the same yarn (and you could always unravel the knitted bottom, wash it, and dry it, and knit with it again); the difference will disappear on blocking. The photo below shows the same sweater after a gentle soak with my new favourite wool wash (available in Hong Kong!), rinse and a run through the spin only cycle of my washing machine. Before you ever put feltable woolens in a spin cycle, make sure that it is not accompanied by a spray or rinse.
It is blocking now, and I will take some modelled shots when we are in Shanghai over Easter.
Traveller's Yarn 
Yeah, you did it! And I’ll have to check out that wool wash.
That is very cool, thank you!
Thanks for sharing. Would never have thought of that, though I’m not confident I could ever pull out a single row of stitches without messing up the whole thing. Yours looks great though!
That looks like it takes quite a bit of bravery – I think I would have had a panic when I saw how different the join row looks! Thanks so much for the pictures – will come in very handy when I (inevitably) need to try just that sort of fix.