Komatsuna (often called Japanese mustard spinach or tendergreen mustard) is a dark-green, cool-season leaf vegetable indigenous to Japan and Taiwan. Komatsuna leaves have a sweet, fresh taste and a crisp, crunchy texture that you can add to salads and stir-fries, boil, pickle, or add to soups. While komatsuna is known as mustard spinach, it’s not related to common [mustard greens](https://www.masterclass.com/articles/how-to-cook-mustard-greens), mustard plants, or spinach. Komatsuna is a member of the *Brassicaceae* family and a variety of *Brassica rapa*, related to [rapini](https://www.masterclass.com/articles/how-to-grow-broccoli-rabe-in-your-home-garden) (also called broccoli rabe), turnips, and napa cabbage.
For best results, plant komatsuna in early spring, a few weeks before the last [frost date](https://www.masterclass.com/articles/how-to-determine-frost-dates-for-gardening-your-region), as soon as you can work the soil in your [vegetable garden](https://www.masterclass.com/articles/tips-for-starting-your-own-vegetable-garden), or as a fall crop after the weather cools in late summer. Avoid starting komatsuna seedlings indoors for later transplanting since the plants have fragile roots that can’t withstand movement from one location to another. 

The optimum soil temperature range for komatsuna plants is 45–95 degrees Fahrenheit. However, temperatures outside of that range aren’t necessarily deadly for the plant. Mature plants can handle brief periods of light frost as low as 20 degrees Fahrenheit, but they will bolt, shoot up flowers, and spoil the flavor in the heat of summer.

After the last frost passes and your soil temperature reaches 45-degrees Fahrenheit, you can plant komatsuna seeds directly into your garden bed:

1. __Prepare the soil bed__. Komatsuna needs full sun to grow, so choose a site that gets at least six hours of sunlight per day. The plants require a good nitrogen supply, so choose well-draining soil rich in organic matter. Consider [amending the soil](https://www.masterclass.com/articles/how-to-adjust-soil-ph-to-help-your-garden-thrive) with nitrogen-rich fertilizer to encourage growth.
2. __Begin seeding__. Sow seeds about a quarter-inch deep, spacing each seed about six inches apart and in rows eight inches apart.
3. __Water__. Komatsuna requires routine watering to grow successfully. Keep the soil evenly moist for seed germination.
4. __Thin__. Once the seedlings are three to four inches high, use shears to thin the seedlings until they are at least 12 inches apart. Thinning the seedlings gives the plant more room to grow and prevents them from competing with nearby plants for nutrients. You can add the thinned seedlings to salads and soups to avoid [food waste](https://www.masterclass.com/articles/how-to-reduce-food-waste-and-repurpose-scraps). 

Komatsuna is an unfussy plant that requires only minimal care:

- __Water__: Komatsuna enjoys moderate water, so keep the soil evenly moist as it grows. Allow the soil to dry between watering to prevent overwatering, which can lead to root rot. Learn more about [how to water a garden](https://www.masterclass.com/articles/how-to-water-a-garden) in our complete guide. 
- __Prune__: Komatsuna will start to bolt in hot weather, sending up flowers and slowing leaf production, making the leaves lose their flavor. Your plant may try to send up flowers periodically while growing, so you’ll need to [prune](https://www.masterclass.com/articles/how-to-prune-your-plants-and-trees) them regularly by pinching off early flower stalks to prevent bolting.
- __Protect__: Komatsuna can be a target for many common garden pests, including flea beetles and caterpillars. Consider [companion planting](https://www.masterclass.com/articles/complete-companion-planting-guide), natural pesticides, or a floating row cover to deter harmful insects. Companion planting, or intercropping, is a gardening practice in which various crops are planted together to increase growth productivity, ward off pests, suppress weeds, and alter soil chemistry.

You can harvest young komatsuna leaves when they are around three inches tall (about 25 days from seed). Harvest mature leaves at any growth stage. (Komatsuna plants typically mature around 40 days from seed.) 

To harvest komatsuna, use shears or a sharp knife to slice outer leaves away from the plant as needed. Leave at least two inches of stem above the ground to allow the plant to continue producing new leaves. At the end of the season, feel free to harvest the entire plant.
Grow your own garden with Ron Finley, the self-described "Gangster Gardener." Get the [MasterClass Annual Membership](https://www.masterclass.com/) and learn how to cultivate fresh herbs and vegetables, keep your house plants alive, and use compost to make your community—and the world—a better place.
If you’re looking for a unique leafy green to plant in your garden this year, consider the unfussy komatsuna plant, commonly known as “Japanese mustard spinach.”

If you’re looking for a unique leafy green to plant in your garden this year, consider the unfussy komatsuna plant, commonly known as “Japanese mustard spinach.”

How to Grow Komatsuna

Komatsuna (often called Japanese mustard spinach or tendergreen mustard) is a dark-green, cool-season leaf vegetable indigenous to Japan and Taiwan. Komatsuna leaves have a sweet, fresh taste and a crisp, crunchy texture that you can add to salads and stir-fries, boil, pickle, or add to soups. While komatsuna is known as mustard spinach, it’s not related to common <a href='https://www.masterclass.com/articles/how-to-cook-mustard-greens' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/how-to-cook-mustard-greens","linkCopy":"mustard greens","category":null}'>mustard greens</a>, mustard plants, or spinach. Komatsuna is a member of the Brassicaceae family and a variety of Brassica rapa, related to <a href='https://www.masterclass.com/articles/how-to-grow-broccoli-rabe-in-your-home-garden' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/how-to-grow-broccoli-rabe-in-your-home-garden","linkCopy":"rapini","category":null}'>rapini</a> (also called broccoli rabe), turnips, and napa cabbage.

What Is Komatsuna?

For best results, plant komatsuna in early spring, a few weeks before the last <a href='https://www.masterclass.com/articles/how-to-determine-frost-dates-for-gardening-your-region' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/how-to-determine-frost-dates-for-gardening-your-region","linkCopy":"frost date","category":null}'>frost date</a>, as soon as you can work the soil in your <a href='https://www.masterclass.com/articles/tips-for-starting-your-own-vegetable-garden' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/tips-for-starting-your-own-vegetable-garden","linkCopy":"vegetable garden","category":null}'>vegetable garden</a>, or as a fall crop after the weather cools in late summer. Avoid starting komatsuna seedlings indoors for later transplanting since the plants have fragile roots that can’t withstand movement from one location to another. The optimum soil temperature range for komatsuna plants is 45–95 degrees Fahrenheit. However, temperatures outside of that range aren’t necessarily deadly for the plant. Mature plants can handle brief periods of light frost as low as 20 degrees Fahrenheit, but they will bolt, shoot up flowers, and spoil the flavor in the heat of summer.

When to Sow Komatsuna

After the last frost passes and your soil temperature reaches 45-degrees Fahrenheit, you can plant komatsuna seeds directly into your garden bed:<ol class="mc-m-4"><li class="mc-my-4"> 1. Prepare the soil bed. Komatsuna needs full sun to grow, so choose a site that gets at least six hours of sunlight per day. The plants require a good nitrogen supply, so choose well-draining soil rich in organic matter. Consider <a href='https://www.masterclass.com/articles/how-to-adjust-soil-ph-to-help-your-garden-thrive' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/how-to-adjust-soil-ph-to-help-your-garden-thrive","linkCopy":"amending the soil","category":null}'>amending the soil</a> with nitrogen-rich fertilizer to encourage growth. </li><li class="mc-my-4"> 2. Begin seeding. Sow seeds about a quarter-inch deep, spacing each seed about six inches apart and in rows eight inches apart. </li><li class="mc-my-4"> 3. Water. Komatsuna requires routine watering to grow successfully. Keep the soil evenly moist for seed germination. </li><li class="mc-my-4"> 4. Thin. Once the seedlings are three to four inches high, use shears to thin the seedlings until they are at least 12 inches apart. Thinning the seedlings gives the plant more room to grow and prevents them from competing with nearby plants for nutrients. You can add the thinned seedlings to salads and soups to avoid <a href='https://www.masterclass.com/articles/how-to-reduce-food-waste-and-repurpose-scraps' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/how-to-reduce-food-waste-and-repurpose-scraps","linkCopy":"food waste","category":null}'>food waste</a>. </li></ol>

How to Plant Komatsuna

Komatsuna is an unfussy plant that requires only minimal care:<ul class="mc-m-4 list-styled"><li class="">Water: Komatsuna enjoys moderate water, so keep the soil evenly moist as it grows. Allow the soil to dry between watering to prevent overwatering, which can lead to root rot. Learn more about <a href='https://www.masterclass.com/articles/how-to-water-a-garden' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/how-to-water-a-garden","linkCopy":"how to water a garden","category":null}'>how to water a garden</a> in our complete guide. </li><li class="">Prune: Komatsuna will start to bolt in hot weather, sending up flowers and slowing leaf production, making the leaves lose their flavor. Your plant may try to send up flowers periodically while growing, so you’ll need to <a href='https://www.masterclass.com/articles/how-to-prune-your-plants-and-trees' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/how-to-prune-your-plants-and-trees","linkCopy":"prune","category":null}'>prune</a> them regularly by pinching off early flower stalks to prevent bolting. </li><li class="">Protect: Komatsuna can be a target for many common garden pests, including flea beetles and caterpillars. Consider <a href='https://www.masterclass.com/articles/complete-companion-planting-guide' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/complete-companion-planting-guide","linkCopy":"companion planting","category":null}'>companion planting</a>, natural pesticides, or a floating row cover to deter harmful insects. Companion planting, or intercropping, is a gardening practice in which various crops are planted together to increase growth productivity, ward off pests, suppress weeds, and alter soil chemistry. </li></ul>

How to Care for Komatsuna

You can harvest young komatsuna leaves when they are around three inches tall (about 25 days from seed). Harvest mature leaves at any growth stage. (Komatsuna plants typically mature around 40 days from seed.) To harvest komatsuna, use shears or a sharp knife to slice outer leaves away from the plant as needed. Leave at least two inches of stem above the ground to allow the plant to continue producing new leaves. At the end of the season, feel free to harvest the entire plant.

How to Harvest Komatsuna

Grow your own garden with Ron Finley, the self-described &quot;Gangster Gardener.&quot; Get the <a href='https://www.masterclass.com/' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/","linkCopy":"MasterClass Annual Membership","category":null}'>MasterClass Annual Membership</a> and learn how to cultivate fresh herbs and vegetables, keep your house plants alive, and use compost to make your community—and the world—a better place.

Learn More

If you’re looking for a unique leafy green to plant in your garden this year, consider the unfussy komatsuna plant, commonly known as “Japanese mustard spinach.”

If you’re looking for a unique leafy green to plant in your garden this year, consider the unfussy komatsuna plant, commonly known as “Japanese mustard spinach.”
