Flax is a plant grown commercially on farms for its seed and oil, but it produces charming tiny true-blue flowers that brighten up the perennial border. Flax are easy to grow and can be grown from seeds planted right in the garden. They grow to about 30 inches high and produce flowers throughout the growing season beginning the second year after planting.
Plant flax in full sun and fertile, well drained soil, similar to conditions where you grow annual or perennial flowers.
Improve the soil. Put a 2-inch layer of peat moss and a 3-inch layer of compost on the surface of the soil. Spread all purpose granulated fertilizer on the surface of the soil, following the manufacturer's instructions as to quantities. Use a spade to turn over the soil to incorporate the peat moss, compost and fertilizer into the garden bed. Rake the soil smooth.
Sow flax seeds directly into the garden where they are to grow. Plant in early spring about 2 to 4 weeks before the average date of your last spring frost. Sow the seeds directly on the surface of the soil and cover with a one eighth inch layer of fine potting soil or peat moss. Flax seeds sown in spring will not bloom until the following year. Sow flax seeds in fall for blooms the following spring.
Water the seed bed with a fine mist from a hose end sprayer. Check the seed bed daily and water as needed to keep the area moist but not wet.
Thin seedlings when they are 2 to 4 inches high so they stand 10 to 12 inches apart.
Water flax at the soil level with a soaker hose to minimize the chance of fungal diseases taking hold on wet foliage. Provide the plants with the equivalent of an inch of rainfall per week.
Mulch flax seedlings with a 2 to 4 inch layer of shredded leaves or buckwheat hulls to control weeds and keep the soil evenly moist.
Remove spent flowers by pruning them off to encourage the plants to produce more blooms. If growing to produce seeds, allow the faded blooms to remain on the plants. Harvest just after the seeds turn brown. Prune out any stems that are fading or that crowd neighboring plants.
Fertilize flax plants monthly during the growing season by spreading all purpose granulated fertilizer on the soil around the base of the plants. Follow the fertilizer manufacturer's recommended quantities.
Mulch flax plants in fall when the foliage dies down. Spread a 4-inch layer of fallen autumn leaves to protect the roots from winter's freeze-thaw cycles. Remove mulch in early spring.