My parents visited a few weeks ago and, as I have mentioned previously, they are the best two people ever anywhere. To this end, my mom offered to knit me a blanket. Woohoo! We decided on the Blessingway blanket by Hannah Cuviello, from the book Knitalong by Portland’s own Larissa Brown & Martin John Brown (published by Stewart Tabori & Chang, spring 2008). It is awesome and cabled, knit in five sections on the bias.
(Photo from Knitalong.com)
But I wanted mine a little bigger, so the obvious solution was to substitute chunky yarn instead of worsted. Dream in Color Groovy in Gold Experience – perfect! But then a question arose that consumed several of us (Mom, me, Parna, Melo, and others) for… well, too long. Would the yardage requirement (1200 yards in this case) remain the same in chunky as it was in worsted? Of course, the finished object will be larger (that’s the whole point), but how much yarn would it use?
Books and patterns were consulted. Calculators were passed around. Ravelry was poured over. Google searches abounded. A few smaller patterns suggested yardage would be the same, but on a blanket any small differences would be magnified significantly. We talked ourselves into thinking it would be about the same. Then we talked ourselves into thinking it would take more – but a lot more or a little more? We couldn’t find any definite answer. What’s a girl to do?
My mom, being a rockstar, put the question to bed with a simple experiment. She is retired now, but after reading the following you will be shocked, SHOCKED, to learn that she used to work as a manager and statistician in a social psych lab. Once a scientist always a scientist. I can’t put it any better than she did so here is her full report:
Question: If the number of stitches per row and the number of rows in a knitted piece are held constant, does the weight of yarn used affect the yardage used?
Method: Two swatches 63 stitches by 72 rows were knit in garter stitch, one in chunky weight yarn, the other in worsted weight. Both yarns were Dream in Color, 100% merino. Needle size differed, selecting the size most appropriate for the yarn weight. The chunky swatch was knit on size 9 needles and the worsted swatch on size 7. (Emily’s note: Mom is a bit of a loose knitter.) The two swatches were then compared for overall size, weight and yardage used.
Result: The chunky swatch measured 17 inches wide and 10 inches long. It weighed 125 grams and used 120 yards. (Emily note: that’s about 3.75 sts/inch.) The worsted swatch measured 13 inches wide and 8 inches long. (Emily note: that’s about 4.75 sts/inch.) It weighed 50 grams and used 91.7 yards.
Conclusion: For a given number of stitches and rows, knitting with chunky yarn on size 9 needles uses about 33% more yardage than using worsted and size 7 needles.
Discussion: The question arose when considering adapting a pattern to a weight of yarn different than specified in the instructions. Using a heavier yarn while keeping the number of stitches and pattern rows the same would clearly result in a larger overall piece, but the effect on total yardage was unclear. These results indicate that when using chunky yarn for a pattern specifying yardage in worsted, the yardage required would have to be increased by one-third. Conversely, yardage requirements given for chunky yarn could be reduced by one-quarter if using worsted yarn. The use of different size needles for the two test swatches affects this comparison, but is justified in order to produce a desirable fabric.