How to Grow Mustard Microgreens in 5 Easy Steps

Growing mustard microgreens gets you a spicy topper for your salads and sushi. Rachel Garcia will guide you through the steps you'll need to get them growing.

Spread of mustard microgreens with vivid green colored leaves on dark brown soil

Contents

If you always reach for the bottle of mustard at cookouts, you’ll love mustard microgreens. These baby greens don’t look anything like the popular condiment, but they pack the same hot and sweet taste. In fact, mustard sprouts are one of the most flavorful microgreens.

Mature mustard plants may give us that familiar yellow color, but they can’t compete with the nutrition and simplicity of mustard microgreens. A serving of mustard microgreens is as good as (or even better) than your store-bought vegetables.

These greens are dense with vitamins A, B6, C, K, E, calcium, fiber, potassium, and more. After all, mustard is part of the Brassica genus, which are some of the healthiest plants out there.

Mustard microgreens look very similar to chia microgreens. They have white stems and pale green cotyledons with a bit of crunch. However, you can make your microgreen garden stand out more by using different mustard varieties.

The ‘Red Giant’ variety, for example, has beautiful burgundy to brown leaves. There are several varieties out there, so your micro garden can look as spicy as it tastes!


Red Giant Mustard

Red Giant Mustard

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Red Giant Mustard Seeds


Mizuna Mustard

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Mizuna Mustard Seeds

Florida Broadleaf Mustard

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Florida Broadleaf Mustard Seeds

What You’ll Need

Mustard sprouts are among the easiest to produce, and growing microgreens is already an easy task! Let’s start by gathering the supplies needed for this easy-to-grow microfood.

Seeds

Tiny sprouts of a plant with rounded leaves with vivid green color contained in a black pot with a brown wooden surface in the background
Different varieties produce different flavors.

There are a variety of different mustards to grow as microgreens. Try some of these:

  • Mizuna Mustard Seeds: A tender, peppery, Japanese mustard green that is milder than other mustards.
  • Gai Choy Mustard Seeds: A classic Chinese mustard that is often used in pickles. It has a mild flavor when in microgreen form. Also known as Indian mustard, mustard cabbage, and Swatow mustard.
  • Florida Broadleaf Mustard Seeds: This is a favorite for Southern gardeners and cooks for its excellent flavor.
  • Red Giant Mustard Seeds: With a hint of horseradish, this red mustard has tons of flavor. It is fast-growing and spicier than other mustards.
  • Must-Have Mustards Baby Greens Seeds: To add a bite to any salad or soup. This mix includes 25% ‘Red Giant’, 25% ‘Tendergreen’, 25% ‘Mizuna’, 15% ‘Ruby Streaks’ and 10% ‘Golden Frill’ mustards.
  • Umami Asian Blend Microgreen Seeds: Savory and spicy notes make this mix the perfect garnish for Asian dishes, meats or salads. This mix includes 32% ‘Tatsoi’ bok choy, 32% ‘Pac Choi’ cabbage, 16% ‘Red Giant’ mustard, 10% ‘Tokyo Bekana’ Chinese cabbage, and 10% ‘Red Streaked Mizuna’ mustard.

Mustard seeds are tiny, so you’ll need a good amount to plant them densely. You can try sowing mustard seeds from the grocery store, but seeds meant for sowing are more likely to succeed.

Containers

Small intact green plants growing in a shallow wooden tray on a wooden surface with another tray of plants in the background along with a container of seeds
Shallow trays work best for these microgreens.

You will need at least two shallow trays, one with drainage holes and one without (you can get a set of these and punch the holes yourself). The one without is used as a cover.

Epic 6-Cell Seed Starting Trays and Germination Domes & Bottom Trays are good choices for protecting the seeds as they grow.

Growing Medium

Sprouts growing for a patch of soil with seed casings scatters near the roots, leaves having a deep green colored hue with light green stems
Use soil mixed specifically to grow seeds.

Microgreens need a fine-grained growing medium, which is why we recommended seed-starting soil. The delicate root system of mustard sprouts will easily navigate through it, as opposed to soil full of debris.

When it comes to mustard, you can also grow microgreens in coconut coir or hydroponically.

Grow Lights

Light green sprouts growing in a small transparent container placed in a white plate with countless dark brown and black mustard seeds
These plants love constant, direct light.

As is the case with all microgreens, mustard sprouts will thrive under a grow light instead of natural sunlight. Since the light can be hung directly above the tray, the sprouting seedlings will grow straight up and uniformly.

When using sunlight, the sprouts will lean towards the light and grow unevenly, giving your micro garden a slightly wonky look.

We recommend starting with the Small Epic Seed Starting Grow Light or the Standard Epic Seed Starting Grow Light for growing microgreens indoors.

Extras

Dark green sprouts growing on a cloth-like material placed on brown paper on a wooden table with a pair of scissors beside it
Use cutting tools to prune these plants.

Sharp scissors, kitchen shears, or pruners are ideal for microgreens (you can use them for other herbs too). You will also need a spray bottle for misting.

How to Grow Mustard Microgreens

Mustard seeds are tiny, round, and dark. Like chia seeds, they get gooey when put in water. It’s pretty difficult to plant a mass of goop, so definitely skip soaking these seeds. Follow the steps for the best results.

Step 1: Plant

Small sprouts with vivid green color and light green stems, having hollow seed casings scattered all over the roots and leaves
Leave small spaces between seeds to allow aeration.

Grab the growing tray with drainage holes and fill it almost to the brim with soil. Smooth out the surface and mist it well with the spray bottle. Using your palms or something flat, lightly tamp down the soil. 

Next, scatter the mustard seeds all across the soil surface. Space them closely enough to grow a mat of greens but far apart enough to allow for good aeration in the trays. Because the soil is already damp, the seeds should stay in place and start germinating right away.

Step 2: Cover

Bright green sprouts growing generously overflowing from a woven container placed in wooden table with seeds scattered all over
Check on these plants regularly and mist if needed.

Grab your second tray (without holes) and set it directly on top of the seeds. It should block out all light and press down on the soil. Add a small weight on top to further press the seeds into the soil. Doing so will help the roots grow down into the potting mix.

Most microgreens can hold up to five pounds, but mustard plants can only take two pounds tops.

Once planted, the mustard seeds will take two to three days to germinate. During that time, you must keep the cover on to keep the seedlings in the dark. You should also check the soil moisture daily, misting as needed.

Step 3: Grow

Someone holding a green spray bottle misting sprouts on a white table with gardening tools and a pot with plants nearby
Water the sprouts when they become dry.

After sprouting, the microgreen plants will push up the cover as they grow. The cotyledons will also be visible. This is your signal to remove the blackout cover and add the grow light about twelve inches above the trays.

The leaves of the mustard greens may be yellow from lack of sunlight, but they’ll quickly turn their full color.

As your microgreens grow, ensure that the soil is consistently moist. When it starts to dry out, reuse the cover tray as a watering tray. Fill it with an inch or two of water and set the growing tray inside. Let the soil absorb the water for about ten minutes, and then remove the watering tray.

This bottom-watering method is the best way to keep your microgreens hydrated without adding excess moisture to the soil surface, which can invite bacterial growth.

Step 4: Harvest

Bright green sprouts in a warmly lit room with light green stems placed on a light brown surface with stray sprouts nearby
The taste and texture depend on its harvest timing.

Mustard greens are usually ready for harvesting between five and fourteen days from planting. This makes them ideal for harvesting as needed, unlike other microgreens that have a short harvest window.

When ready to be eaten, the cotyledon leaves will be fully opened and the microgreen will have one to three inches of growth. However, they should be harvested before the first true leaves show up, as the taste and texture of the microgreen will change drastically.

Since we’re removing all the leaves, mustard microgreens are a one-and-done plant. You can pull out the spent seed and reuse the soil, but keep in mind that it will lose nutrients and gain bacteria over time. The best option is to compost the soil into some organic growing medium for another project.

Step 5: Store

A spread of bright green sprouts in a someone's hands with nails colored a deep green, receiving direct sunlight
These plants taste best when fresh.

Before you eat your harvested microgreens, give them a good wash (some organic gardeners skip this step). Then, add them to any food that needs some spice. Fresh mustard microgreens are fantastic as herbs with salad, sandwiches, hotdogs, and a number of Indian dishes.

Unused microgreens should be sealed in a plastic bag and kept in the fridge (in a paper towel to absorb moisture if needed). They should stay good for around ten days. Like most fresh food, they should be eaten as soon as possible for the best taste and health benefits.

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