How to Grow Brassica Juncea

Prepare the soil to grow mustard greens. Spread 2 to 4 inches of a combination of peat moss and compost on the surface of the soil in the row designated for mustard greens. Add 4 to 6 cups of granulated all-purpose 10-10-10 fertilizer for every 100 square feet of growing bed. Dig the amendments into the soil by turning it over with a shovel. Smooth the surface with a garden rake.

Sow seeds of mustard greens in early spring, as soon as the soil temperature reaches 40 degrees Fahrenheit. Plant seeds 1/2 to 1 inch deep. Firm the soil over the seeds gently with your hand and water the newly planted seeds with a finely misting hose nozzle.

Thin plants when the seedlings have three to four true leaves. Remove enough seedlings so that the remaining plants stand about three inches apart in rows 12 inches apart.

Water mustard greens as needed to keep the soil evenly moist but not wet. Fluctuations in moisture levels in the soil cause the leaves to develop slowly and become tough and off-flavored.

Mulch the soil around the plants with a 3-inch layer of hay, straw or other organic matter. This keeps the soil cool and evenly moist, which helps keep the mustard greens from developing an off taste.

Apply a dose of fertilizer about four weeks after thinning the seedlings. Use 1/2 cup of 21-0-0 granulated fertilizer for each 10 feet of row. Sprinkle the fertilizer alongside the plants, about four to six inches away from their bases. Incorporate the fertilizer into the soil by watering with an overhead sprinkler.