r ranson wrote:Oh dear, this is a really tricky question. I wish I had a simple answer for you.
A lot of it depends on how experienced you are at processing. If you are just learning, you probably need four times as much flax as someone who has been processing for a few years. Then there's the weather and the soil and the wind... Some years I can get two or three times the average amount of fibre out of a patch. Sometimes, less than half. Different patches around the farm produce vastly different amounts of fibre for the same amount of space and seed.
Generally, when we are starting out, the limiting factor is the seed. Grow as much as you have seed. Observe what it's like for you, in your growing conditions, your soil, your climate. Save the seeds for next year and base your space on that.
If you want numbers, a 5x10 feet bed of flax usually gives enough for a pair of handwoven towels (on the West Coast of Canada). Clothing would probably be spun quite a bit thinner, so it might be enough for a top.