Seeding rate of fiber flax in the Willamette Valley of Oregon is between 100 - 150 lbs/acre, depending on seed size and germination rate.
We have recently had success seeding fiber crops at 120 lbs/acre, and seed crops at 66 lbs/acre.
The optimum stand densities for fiber flax are 175 to 200 plants per square foot.
Flax grows best in 6.0 - 6.5 pH soil.
How to plant fiber flax (small plots)
Choose a site in full sun, with deep, fertile, well-drained soil. Flax grows best in 6.0 - 6.5 pH soil.
Prepare the plot as you would for growing vegetables or flowers.
Flax grows best in cool weather, so plant as soon as you can work the soil in early spring or overwinter a flax crop by planting in late fall. Currently, spring planting is best before the end of April and fall planting is done around October 15- November 1.
Broadcast seed over planting area. We have used a rate of 120 lbs/acre.
Use a rake to cover seed lightly with soil.
Then roll over the seed with a lawn roller or similar tool, compacting the seed bed. This is a very important step! You should be able to walk on the soil and not leave a footprint.
Water just enough to keep soil moist until germinated. You should see sprouts in about a week or so...
Then, let spring rains irrigate; if no spring rain, keep soil moist and water about 1” per week, through blooming phase, and up until seed heads form.
Once seed heads begin to form, no more water. This will prevent lodging.
For fiber crops, harvest when plants are about half yellow/half green.