Mustard Herb Growing Guide

How to Grow Mustard Herb from Seed

  • Scientific Name: Genus Brassica and Sinapis
  • Hardiness Zone: Annual to Zones 3-9
  • Days to Harvest: 80-90 days
  • Days to Maturity: 80-90 days
  • Days to Germination: 7-10 days
  • Seeding Depth: ¼-½”
  • Plant Width: 12-18"
  • Plant Height: 12-18"
  • Growth Habit: Mounding leafy green
  • Soil Preference: Fertile, loamy, well-drained
  • Temp Preference: Cooler, 45-75°F
  • Light Preference: Full sun - partial shade
  • Pests/Diseases: Susceptible to both leaf-eating and sap-sucking pests such as caterpillars, snails, slugs, aphids
  • Availability: See All Mustard Varieties
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Growing Mustard

Mustard is an annual herb that is native to certain regions in Europe, with roots in Asia, North Africa, and the Middle East as well depending on the variety of mustard. It is a cold-hardy annual and prefers cooler temperatures. Mustard has an extensive history, spanning back to the Stone Age and ancient Egyptian civilizations for its culinary and medicinal uses. All parts of the mustard plant are edible, and its seeds are used to create the condiment that we know and love as mustard, too. This condiment is usually made from white and black mustard seeds, as brown mustard is known to be very spicy. Mustard plants can grow up to 3 feet tall and is known for its yellow flowers that adorn it in groupings of two to twelve. These flowers are commonly consumed as well as used in everything from teas to garnishes for fancy plating of dishes.

How to Grow Mustard from Seed

  • Add compost before sowing seeds
  • Plant ¼-½" with a spacing of 6-8” between plants
  • Make sure it is planted where it can receive full sun to partial shade

When planting mustard, it is important to ensure that the soil is prepared and has enough nutrients in it. A popular way of preparing soil for this herb is by adding compost in before sowing the seeds. Upon placing the seeds, the planting depth for mustard is ¼ to ½”, with a planting space of 6 to 8” between each plant. Mustard is usually planted after the last frost of the season but can be planted as early as 4 to 6 weeks before as it is cold hardy. It is usually planted in the fall or spring. Mustard thrives in full sun to partial shade conditions, with a decent balance between the two, and it is easily germinated with germination usually occurring after 8 to 10 days of sowing seeds but in some cases earlier than that. To ensure optimal growth and health, it is important to make sure that the soil is well-drained to avoid over-watering and retention of too much moisture.

Mustard Soil

To grow properly, mustard prefers a soil that’s pH is above 6.0, but will still grow in acidic conditions. It needs consistent moisture, especially when it is in the beginning stages of growth, to ensure that it produces its leaves quickly. The soil needs to be well-drained to ensure that the plant does not receive too much moisture as this is not good for its well-being. It requires around two inches of water a week. It is important to keep an eye on rainfall, as you may need to water it less or none at all during rainy weather conditions. Do not let the soil dry out, as this will kill the plant quickly. Mustard thrives with addition of aged compost to its soil before sowing seeds. Mulch is not necessary for its growth, but if you have issues with your ground retaining moisture it may be a helpful addition to the livelihood of your mustard plants.

Watering Mustard

  • Make sure that the soil is moist and well drained at all times
  • Check with fingertips to ensure that the soil is not dry nor too wet
  • Needs around 2” of water a week

Mustard prefers cooler climates but will tolerate hotter climates, as long as it is not exposed to too much heat in the early stages of growth or flowering. Too much heat can cause regression of growth and the plant to die, especially if the heat causes it to not retain enough moisture. Mustard prefers rich, well-drained soil. It does well in full sun but prefers partial shade as well, as too much sun can cause it to lose moisture quicker. To prevent over-watering, you may check the soil with your fingertips to ensure that is not soggy but rather moist to the touch.

Is Mustard A Perennial?

Mustard is not a perennial, but it is an annual. It does not grow back year after year, but rather has an entire life cycle in one season and then dies. Because it is an annual, new seeds need to be sown each year. For an annual plant, the dormant seed is what allows these plants to continue to grow from one season to the next. Once the plant dies, it will not come back unless these new seeds are replanted the following year. Some plants may be annuals and perennials both, according to the zone and climate that they are in. This is not the case with mustard plants, as they are all annuals no matter where they are planted.

Mustard in Winter

  • Able to grow annually in the warmest winters
  • Not tolerant of heavy frosting
  • Still needs plenty of sunlight

Mustard is hardy and prefers cooler temperatures, germinating best at a soil temperature of 45 degrees Fahrenheit, but will be slow to germinate if the soil temperature is below 40 degrees Fahrenheit. Its seeds are usually sown in fall or early winter in regions that have milder winters. Mustard is tolerant of light frosting, which actually changes the taste of their leaves from more bitter to sweeter. Mustard usually survives throughout winter and even thrives then for many gardeners as long as there are no heavy freezing temperatures. Living in areas that experience freezing frequently may cause gardeners to opt in transporting mustard plants inside during the winter to avoid the possibility of it diminishing.

Growing Mustard in Pots

Mustard grows well and can easily thrive in a pot! It easily germinates within 10 days at most and is tolerant of being grown inside as well as it is outside. You may also consider starting it inside and once it has reach substantial height, transplanting it outside. However, this is not necessary if you wish to keep it inside. It is important that if you decide to grow it inside you ensure that it receives enough sunlight but not too much as to dry the plant out since it prefers some shade as well. Make sure that when you are choosing a pot for growing mustard in it if you choose to do so, that it has draining holes in it so that the soil can remain well-drained at all times. Water the plant evenly and consistently. Regardless of location, these are the best conditions for mustard to thrive in.

How to Care for Mustard Plants in Pots

  • Make sure it receives enough water
  • Make sure it receives enough sunlight and shade
  • Regularly check it for mildew and pests

To care for mustard if it is planted in a pot, ensure that it is receiving enough water and that the soil is moist, but not soggy or too wet. The pot needs to have drain holes to ensure this. It is also recommended that the plant receives ample sunlight and shade. Shade is good for the plant, and it is beneficial to mustard’s growth to not always be in the sun. It is important to check it regularly to ensure that it is not affected by any diseases or pests. Mildew occurs often in indoor plants, particularly if they are over-watered or confined near other plants.

Growing Mustard Indoors

This herb is not popular or known for being grown indoors, but rather it is known for growing best outside. However, it can still grow and thrive inside if chosen to with some work and extra care. Mustard is not a picky herb in the sense that it does not need a lot of heat or cold to thrive, but rather it can tolerate moderate temperatures well and is not easily phased by some colder weather. Mustard does well with sunlight and shade both and prefers a mixture of both. Mustard can easily thrive as an indoor plant with proper care and caution of the plant’s needs. When growing mustard inside, it’s important to be aware of the fact that the plant tends to grow to be taller than an average indoors plant (3 ft usually), so make sure you have ample room for the plant to grow to its full potential.

Mustard Companion Planting

Among mustard’s companion crops are known to be yarrow, dill, and plants within the mint family. Since mustard can fall victim to pests such as aphids and flea beetles, these plants aide mustard by preventing these pests from eating or destroying its leaves. This is possible due to yarrow and dill attracting ladybugs and lacewings, which feed on aphids. Plants within the mint family, such as mint and lemon balm, repel flea beetles. By strategically placing these companion plants together, it helps remove the possibility of damages to the plant from outside forces. Plants that may benefit from mustard are fruit trees as it helps stimulate their growth. It’s important to not place mustard near bean plants as this can cause them issues with mildew, as well as a struggle for sunlight.

Mustard Flowers

Mustard is known for its bright yellow blooms, reminiscent of the yellow mustard condiment that is made from its seeds. Mustard flowers are characterized by four yellow petals attached to a center with a short and thinner stem. These flowers grow in clusters of two to twelve. The scent that radiates from mustard’s flowers has been described as smelling very pleasant; it has been described as smelling like a mixture of honey and spice, and their scent reminding some of sweet clover. Mustard flowers are edible as well and add a creative (and beautiful) element to salads, are commonly eaten boiled, and may be used in teas as well as other parts of the mustard plant. It is known to help with headaches when drunk as a tea.

Harvesting Mustard

Mustard greens may be harvested throughout the season, as long as they are sprouting. As a rule of thumb, it is important to never harvest more than 1/3 to 2/3 of the plant at one time, so that it will continue to grow. If you want to continue growing leaves longer, pluck off the flowers as they come in. Once the flowers blossom, the leaves will no longer grow. A popular way of harvesting mustard seeds from their pods is by pulling up the plant and hanging it upside down in a paper bag and allowing it to dry out. After two weeks, shake the bag and the seeds should fall out of its pods and drop to the bottom. This method is the hang dry method.

When to Harvest Mustard

  • Before its flowers blossom
  • When the seed pods have become mature
  • When there are enough leaves to safely remove 1/3 to 2/3 of the plant

How to Harvest Mustard

Mustard may be harvested by using scissors or garden shears to snip the flowers, leaves, and stems. In the case that scissors are not available, hand-picking these works as well. If the plant is being harvested for its leaves and seeds, the flowers are usually snipped off before they fully blossom, because if they fully blossom then the leaves will stop growing. You may harvest the leaves and pods by cutting the stem and drying them out for an easy removal.

Drying Mustard

When harvesting mustard, it is recommended that the seeds be dry. Perhaps the easiest way of harvesting mustard seed is to uproot the entire plant and hang it upside down in a paper bag to try. The recommended wait time for it to fully dry is two weeks. Another convenient way of drying them is to pluck the individual pods and dry them on a screen for two weeks in a single layer as well. When harvesting mustard, if the seeds are already not dry enough, these methods work nicely along with other alternative methods: oven drying and using a food dehydrator. It is important to make sure that you harvest the pods before they are fully mature to prevent them busting open from brittleness and spreading seeds everywhere. The ideal moisture content for mustard seed storage, according to E.S. Oplinger of the University of College of Agriculture, is 10%. Similarly, as being too dry can cause issues with mustard seeds, containing too much moisture can cause it to spoil. This is why making sure you use drying methods as needed is so important in handling and harvesting mustard.

How to Dry Mustard

Hang Dry: Place stem with pods and leaves attached to it in a paper bag and hang it from a string in a dark, dry area. After about two weeks it should be completely dry. Once two weeks have passed, lightly shake the bag to remove the seeds from their pods.

Oven Dry: To oven dry mustard leaves, preheat oven to 200°F. While the oven is preheating, place the leaves on a tray and when it is finished, place in the oven and turn the oven off. Leave the door of the oven cracked for air circulation and let leaves sit until dry. It should take around 20 minutes. If they aren’t fully dry after 20 minutes, let them sit in the oven until fully dry.

Food Dehydrator: When using a food dehydrator to dry mustard leaves, preheat it to the lowest temperature setting (likely around 95-115°F). Place leaves on drying rack and let them sit until dry, possibly up to 12 hours or more. It may take less time, it just depends on the overall moisture content within the leaves.

Types of Mustard

There are three major species of mustard, often considered white, black, and brown mustard. White mustard (Sinapis alba) grows wild in North Africa, the Middle East, and Europe. Brown mustard (Brassica juncea), originating from the Himalayas, is grown mainly in India and is very popular in Indian food culture as it is commonly used in cultural dishes for spice. Black mustard (Brassica nigra) is grown in Argentina, the U.S., Europe, and a few other countries. The mustard condiment that is often consumed here in the U.S. is made from white mustard seeds or black mustard seeds rather than brown mustard as it is the spiciest of the other two. Black mustard seed oil is also commonly used for medicinal purposes, being used as a tea to treat everything from the common cold to arthritis.

Benefits of Mustard

Mustard is known for being a culinary herb, but also carries many medicinal properties as well. It has been studied for its chemoprotective properties on cells regarding cancer and treatment thereof, is a great source of antioxidants if being consumed (particularly the leaves), and even has antibacterial properties due to one of its constituents, allyl isothiocyanate, which gives mustard its unique taste. Black mustard oil is particularly known for its effects on the common cold, inflammation and muscle pain, along with aiding effects of arthritis.

Historically, the Greeks and Romans popularized medicinal use of mustard. They used it as a cure for many different ailments, spanning from hysteria to snakebite and more. Mustard is also a known diuretic, with claims that it has helped stimulate and aid digestion in people who regularly consume it. In mentioning mustard’s medicinal properties, it is also important to note that one cup of mustard greens increases your daily value of vitamin K by 500%, Vitamin K is vital for blood clotting and other functions that the body carries out daily.

Additional Information on Mustard Herb

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