How to Grow Astragalus Membranaceus

Rub your Astragalus seeds lightly with sandpaper to scratch the seed membrane, and soak them in water overnight.

Plant each seed one inch deep in a two-inch peat pot full of dry potting soil, and place in a sunny window. Use one seed per pot, and add just enough water to each to slightly moisten the soil. Keep the soil just barely moist as the seed germinates.

Transplant the sprouts to larger pots as they grow, generally about every 2 to 3 weeks, beginning when the sprout is about three inches high. Keep the soil dry, and make sure they are exposed to full sunlight at least eight hours per day. Some growers have success using full spectrum grow lights during the part of the day the windowsill is shaded.

Purchase a soil test kit from a nursery, and use it to determine where your garden has alkaline soil. The soil should also be dry enough that it does not hold together when you squeeze a handful of it. This is the perfect location for your Astragalus. Be very sure that no shadows are cast over the site at any point in the day - Astragalus cannot grow in the shade.

Plant your seedling in spring, after the last frost. The seedling's size will vary according to when you germinated the seed. Dig a hole deep enough to accommodate the roots, and slightly wider than the root ball. Remove large stones or other hard debris from the hole, and push mulch about three inches back. Carefully remove the seedling from the container, and gently shake off loose dirt. Place the seedling into the hole, and fill with dirt, but do not pack the soil.

Water the plant lightly after planting, but only water when droopy and wilted from then on. Make sure the soil stays dry and sandy. Many Astragalus plants receive all the water they need from rain. If you get a very rainy season, add gravel to the soil to allow efficient drainage.

Harvest the roots of the three-year-old plant in spring or autumn. Thoroughly clean and dry the root, and slice for use. If you wish to keep the plant, harvest no more than 30 percent of the smaller peripheral roots, leaving the main taproot (the long, thick one in the center) intact.