A mustard plant produces tasty leaves that are commonly enjoyed in salads, and is also responsible for the seeds that create the well-loved condiment. This cool-season vegetable comes in yellow, brown and Oriental varieties and typically grows in four to five weeks. With proper care, mustard seedlings emerge without complication.
Prepare a nutrient-rich, well-draining soil for your mustard seeds. Make sure the dirt contains no plant debris. Combine a fertilizer with a nitrogen, phosphorous, potassium (NPK) rating of 16-16-8 or 10-10-10 with the upper 6 inches of soil. Test the level of soil firmness by standing on the planting area to see if your shoe leaves a shallow impression; if it does not, pack in more soil.
Select a planting date for your seeds three weeks before the last frost in early spring and then three weeks later (if desired) for a fall harvest. For example, the North Dakota State University and Purdue University websites suggest sowing seeds between May 1 to May 25 for Minnesota, Wisconsin and North Dakota. This date is important because frost can kill mustard plants and seeds only push through the soil (germinate) at temperatures no lower than 40 degrees Fahrenheit.
Plant the mustard seeds 1/3 to 1/2 inch deep in the soil. Position the seeds 3 to 5 inches apart and space any rows 12 inches apart.
Keep weeds away from your mustard seedlings. Weeds steal vital nutrients away from your mustard plants.
Water the soil to keep the texture moist. Do not water so much that your plants become waterlogged.