How to Grow Delicious Mustard Greens in Your Garden

Green mustard
Fajrul Islam / Getty Images

Mustard, the nominal head of the Brassica family of plants, can check off multiple garden roles; it functions as a cover crop that wards off pathogens and provides distinctive culinary seeds. This plant is hardy, less susceptible to the typical troubles of cole crops, and adaptable—but could be considered invasive if let loose. Even beginners and those with brown thumbs are bound to succeed at growing mustard greens.

Botanical Name  Brassica juncea
Common Name  Chinese mustard, brown mustard
Plant Type  Annual with basal leaves forming a loose bunch
Days to Harvest  40-50 days
Size  8-24 inches
Sun Exposure  Sunny to partial shade
Soil Type Well-drained and fertile, with lots of organic matter
Soil pH  6.0 to 7.5
Hardiness Zones  2-11
Native Area Asia, North Africa, and Europe

How to Plant Mustard

Mustard is a cool-weather crop, like many leafy greens and Brassica relatives, and can even tolerate a light touch of frost, once it is mature. Plant at the tail-end of winter or early spring and then again in early fall for a late fall harvest. Choose your planting dates according to the frost dates for your area.

An Important Note on Frost Dates

Most tender plants can not tolerate freezing temperatures, as the water in their cells expands and bursts the cell walls. However, many plants in the cabbage family can endure a kiss of frost if they are mature; it may even improve their flavor. By looking up your frost dates, you will know when it is safe to plant or transplant your crops. Keep in mind that these dates are based on the past 30 years of data, and climate change has noticeably altered old weather patterns.

Growing From Seed

Mustard seeds germinate best at  55-65 degrees F, and the plants will grow best when the weather is cooler than 75 degrees F. Directly sow seeds ⅓-½ inches deep in rows one to two feet apart. Plant seeds 3-5 inches apart, otherwise you will have to thin them and transplant or eat the immature plants. Cover the seeds lightly and make sure the soil does not dry out while they are trying to germinate.

Mustard Plant Care

Because it grows quickly, mustard gets around many challenges and even outpaces some weeds. It simply needs reasonable soil, consistent water, sunlight, and a little monitoring for insects.

Light, Soil, and Nutrients

While a floating row cover will protect young plants from pests and cold weather, closer to harvest time, mustard leaves need sunshine to maintain their deep green color and their full measure of nutrients in the leaves.

Prepare the soil ahead of planting to ensure that it is friable, fertile, and deep enough for the plant's very determined root, which can reach 3 feet in length or longer if desperately searching for water. The University of Arkansas Division of Agriculture states that mustard seeds will germinate when the soil is 45 degrees F or higher; gardeners should adjust their growing times according to their region and climate. Mix in a complete and organic fertilizer ahead of planting to give the mustard a good start. A side-dressing of nitrogen-rich fertilizer, applied when the plants have several true leaves, will help mustard grow quickly and reach maturity before problems can develop.

Water, Temperature, and Humidity

The soil around the mustard plants should be kept consistently moist, so make sure to water regularly. Mustard is cold-hardy, and particular curly varietals can even tolerate a little frost. Mustard prefers cool to mild temperatures, especially when it is near maturity. Too much heat at harvest time results in a bitter flavor.

Common Pests and Diseases

Flea beetles, cabbage worms, and aphids are the most common pests, but you can prevent an infestation with a floating row cover while plants are young.  Mustard is fairly resistant to diseases, but rotating crop locations and alternating with non-Brassica crops will help the mustard avoid soil-borne pathogens like powdery mildew or blights.

Mustard Varieties

  • Tendergreen: With its broad, flat, dark green, smooth-edged leaves, tender green mustard is also known as Japanese mustard spinach. It is more heat resistant and long-lived than spinach.
  • Red Giant: This fast-growing varietal has large crinkly leaves, a deep maroon color, and a milder flavor. Its smaller cousin, Osaka Purple, adds color and bite to a salad or stir-fry. 
  • Curly: Green Wave and other curly-edged mustards have a bright green color. These varieties are spicy when raw but become milder when cooked.
  • Mizuna: With a peppery flavor and slight bitterness, this mustard green has frondy leaves and tender stems that are great for cut-and-come-again harvesting over a season. It is usually eaten cooked.
  • Tatsoi: A little slower to reach maturity, Tatsoi forms pretty rosettes and has crunchy stems along with deeply colored leaves.
  • Wasabina mustard: While hot like its namesake, this is not the true wasabi plant used in Japanese cooking.

Which Is Best For Its Seeds?

The above mustard plants produce brown seeds that are strongly spicy. The milder type, used for yellow mustard and pickling, comes from white mustard, Sinapis alba. Both white mustards and brown mustards can be used as a cover crop, and several mustard mixes are available from seed sellers.

How to Harvest Mustard

Mustard reaches harvestable maturity in about 45-55 days. The younger leaves, 4-5 inches long, are more tender and less bitter. You can harvest the whole plant or cut outside leaves and allow new leaves to grow from the center. Vegetable Specialist Daniel Drost recommends that all harvesting take place before the seed stalk forms. Mustard varietals can also be grown and harvested as baby greens or microgreens.

How to Store and Preserve Mustard

The University of Illinois Extension recommends storing mustard greens in a plastic bag in your refrigerator's crisper. To extend the life of fresh leaves, wrap them in a moist paper towel first. Mustard greens can be frozen if you have an abundant crop. Blanche for exactly three minutes, plunge into very cold water, drain, and store in freezer-safe bags or containers.