How to Grow Mustard Seeds

By Heather Rhoades
Published: November 1, 2015 | Last updated: May 5, 2021
Key Takeaways

Many people do not realize that mustard seeds come from the same plant as mustard greens. This versatile plant can be grown as a vegetable and eaten like other greens or, if allowed to flower and go to seed, mustard seeds can be harvested and used as a spice in cooking or ground into a popular condiment. Learning how to grow mustard seeds is easy and rewarding.

How to Plant Mustard Seeds

Mustard seed plants are normally grown from seed, but can be grown from seedlings as well. Any mustard plant grown for greens can also be grown for mustard seed.


If growing outdoors, plant the mustard seed about three weeks before your last frost date, or anytime indoors.

Since you will be harvesting the mustard seed, there is no need to space out plantings like you do with mustard greens. (Read more: Moving Plants Inside for the Winter: What You Need to Know)


Plant your mustard seeds about an inch apart. Once they sprout, thin the seedlings so they are 6 in. apart.

Mustard plants grown for seed are planted further apart than plants grown for leaves, as the mustard plant will be getting much larger before it flowers.

Growing the Seeds

Once mustard seed plants start growing, they need little care. They enjoy cool temperatures and will bolt (flower) quickly in warmer temperatures.


While this may seem like a great thing if you are looking to grow mustard seeds, it is not. Mustard plants that bolt due to warm weather will produce poor flowers and seeds. It is best to keep plants on a normal flowering cycle.

Mustard seed plants need 2 in. of water a week. They do not need fertilizer if they have been planted in well-amended garden soil, but if you are unsure if your soil is nutrient rich, you can add a balanced fertilizer to the roots once the plants are 3 or 4 in. tall.


How to Grow Mustard Seeds

How to Harvest Mustard Seeds

Mustard plants will eventually flower and go to seed. The flowers are generally yellow, but some varieties have white flowers. As the mustard flower grows and matures, it will form pods. Watch for these pods to start to turn brown.

Another sign that you are nearing harvest time is that the leaves of the plant will start to yellow. Be careful not to leave the pods on the mustard seed plant for too long as they will burst open when fully ripe and the mustard seed harvest will be lost.

The next step is to remove the seeds from the pods. You can do this with your hands, or you can place the flower heads in a paper bag and allow them to finish maturing.

The pods will open on their own in 1-2 weeks and a gentle shake of the bag will shake loose most of the mustard seeds.

Mustard seeds can be used fresh, but like other herbs and spices, if you plant on storing them long term, they will need to be dried.

Article Source:


Makes about five 4 oz. jars

Pair this tangy-sweet mustard with smoked meats, salami or well-marinated grilled meats. And, of course, bratwurst.


PRESERVING METHOD: Waterbath Canning


  • 11/2 cups beer
  • 1 cup brown mustard seeds
  • 1 cup water
  • 1/2 cup malt vinegar
  • 1/2 cup lightly packed brown sugar
  • 1/4 cup dry mustard
  • 1 tbsp. onion powder
  • 5 (4 oz.) glass preserving jars with lids and bands


1. COMBINE beer and brown mustard seeds in a medium saucepan. Bring to a boil. Remove from heat, cover and let stand at room temperature until seeds have absorbed most of the moisture, about two hours.

2. PREPARE boiling water canner. Heat jars and lids in simmering water until ready for use. Do not boil. Set bands aside.

3. PLACE mustard seeds and remaining liquid in a food processor or blender. Process until chopped and slightly grainy.

4. TRANSFER mixture to a large saucepan. Whisk in water, vinegar, brown sugar, dry mustard and onion powder. Bring to a boil. Reduce heat and simmer, stirring frequently, until volume is reduced by a third, about 15 minutes.

5. LADLE hot mustard into hot jars, leaving 1/4 in. headspace. Remove air bubbles. Wipe rim. Center hot lid on jar. Apply band and adjust until fit is fingertip tight.

6. PROCESS in a boiling water canner for 10 minutes, adjusting for altitude. Remove jars and cool. Check lids for seal after 24 hours. Lid should not flex up and down when center is pressed.


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Written by Heather Rhoades

Profile Picture of Heather Rhoades

Heather Rhoades is the founder of Gardening Know How, where she continues to write articles and answer questions relating to gardening.

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