How To Grow Wasabi: Step-by-step Guide

For sushi or sashimi, wasabi reigns supreme -however, only a small portion of what you buy in the name of “wasabi” in the United States is real wasabi, as real wasabi is extremely difficult to grow. Most of the time, the vibrant wasabi paste you find in these tubs is European horseradish that has food coloring! However, for those who love Japanese food making real wasabi is well worth the effort. Freshly grated and with nutrients, it’s not easy to grow, but it’s doable when you are aware of how to grow wasabi.

As a part of the Brassica family, the Wasabia japonica plant is known as a cool-weather cultivator. It is native to streams in the mountains of Japan It is essential to recreate the moist, rocky, and well-drained habitat the plant was first developed. Shade is essential and so is slightly sulfurous soil, as well as extremely consistent watering as well as weeding. It is a rhizome-based plant that will take a couple of years to develop. It isn’t easy to self-seed but the majority of people find plants to start their harvest.

A lot of areas in The Pacific Northwest and British Columbia have successfully kept farms that grow this plant, where the swathes of roots and leaves reside in gravel beds that are mounded while water flows steadily through. There are 18 kinds of wasabi but in the US you’ll only come across the mazuma or daruma varieties.

It is a popular choice for people to grow wasabi whether in greenhouses or extremely shady parts of their yards every year. Although it can take up to two years before your plant can reach full bloom, the cultivation of this rhizome that is green is achievable at home. And while you wait you can pick delicious leaves that you can use!


  • Subtropical perennial
  • Tolerance of mature plants 27-80deg (-3-27 deg C) The ideal range is 45-65deg (7-18 deg C)
  • Full shade; fertile, moist soil; pH 6.0-7.0
  • Plantlets or wasabi seeds can be started up to 18+ months until harvest.

All About Wasabi

Wasabi originates from Japan and is recognized throughout the world for its ability to make sushi pop. The root is then ground into a wasabi paste and then is served with a variety of seafood or vegetarian sushis. Although it was originally employed for its antibacterial qualities to be eaten along with fish, it’s now mostly used to add flavor rather than as a food-safe Sanitizer.

The wasabi plant, known as Eutrema japonica develops through an underground rhizome that runs along streams in shady regions and cool temperatures of mountainous Japan. The plant is slow to grow, and the entire plant could take several years to develop to its full maturity. Wasabi roots are the most sought-after part of the plant when the entire plant is eaten.

The advantages of the plant, when it is grown in the home with seeds or rhizomes are unquestionable. Although initially, it was only eaten as raw fish it is consumed for its leaves, which can be preserved using salt and sugar to create a dish known as Azuke. In addition, the leaves can be cooked and eaten as salads.

Strange-looking plants fresh wasabi is grown in aquaponics, a soil that doesn’t hold water or gravel. The wasabi rhizome grows underground and appears like a taproot that has swollen and rises above the soil once it’s fully grown and ready for harvest. Rhizomes can be found in sizes ranging between 1 to 2″ and reach a depth of up to 18″. They grow several leaf stems that reach as high as 24″ in the height.

Heart-shaped, large, and vibrant green leaves rest on the stems and absorb whatever direct sunlight the plant needs. Although it does not always bloom, however, it can bloom in the early spring, and it can produce more seeds, which can be used to propagate. It can take between 60 and 70 days for the pods of seeds to develop, they grow along the long and skinny stems. They appear similar to tiny pea pods. There are between 2 and 6 seeds in each pod.

Because of the region of the world the plants developed in, if you’re growing wasabi seeds it is necessary to divide them. Create a fake winter by placing it in the refrigerator for two to three months. This will help the seed determine when it’s the right time to end the dormancy stage and start to sprout.

Planting Wasabi

wasabi plant illustration

If you’re growing fresh wasabi using plantlets i.e. smaller growths that are part of a rhizome from a larger wasabi plant, it’s recommended to begin your wasabi plants in autumn. Wasabi grows best in the cooler months specifically between autumn and spring when temperatures are cold and the wasabi plants are more likely to get a regular supply of water (either rainwater or distillate water).

In the fall, put your plantlets in well-draining soil or gravel, or a medium for rooting similar to vermiculite. It is widely regarded as a difficult plant to cultivate The wasabi root is usually propagated via vegetative propagation, which is the plucking of small plantlets from the top that is the plant’s mother, and put in the optimal, moist, and shady environments to create the whole set that includes wasabi plants. This is thought to be the most efficient method to produce large amounts.

Though it is commonly grown within the United States in the Pacific Northwest along the Oregon coast This semi-aquatic plant may be grown in aquaculture or raised beds with organic soil as well as a well-draining gardening medium. Wasabi requires an environment similar to the soil they developed along riverbeds. Therefore, running water is optimal, hence the appeal of aquaponics. If you don’t have these conditions Wasabi can be a victim of most fungal illnesses since the wet soil incubates a range of illnesses.

For planting, you can use the tatamishi system, which is a Japanese rock mat that circulates cool water, allowing the soil to drain quickly. Beds may differ in length and width however, they are made up of two” of sand, over 3″ of gravel, and then 16-40″ of smaller rocks in the bottom layer. Within the bed is a slope between 1-4 percent, which creates an endless river of water. It is best to transplant plants when they’re approximately 1.5″ in height and are sprouting 4 or 5 true leaves.

Many growers also plant wasabi inside containers. Wasabi growing is much easier to control in such a setting because a lesser amount of gravel, sand or drainage medium is needed to manage the growth environment. The growers can also make use of shade cloths to keep newly planted plants out of direct sunlight or put the plants in a greenhouse that is complete shade.

If you are growing wasabi on the soil, plant plants with a minimum of 2″ to accommodate their long roots in containers that are deeper than normal. The roots require more space than others for growth.


wasabi leafes

Wasabi growing is difficult, as they are considered one of the toughest plants to cultivate. But, one rhizome could yield more than one harvest with enough time and careful cultivation. This edible rhizome can be very careful about how it is treated and requires a gardener who can most closely replicate the conditions.

Sun and Temperature

Wasabi thrives in moderate temperatures. Wasabi leaves require a shaded area with no direct sunlight or heat and a temperature range between 46 and 70 degrees Fahrenheit. At temperatures above 80 degrees, the wasabi plants will die, whereas below 27 degrees, the wasabi plants are susceptible to freezing.

You can replicate these conditions by offering shade with shade cloths or large trees for shade. Incorporate compost into your soil to a thickness of 10 inches to supply nutrients and shield root systems from severe temperatures.

Water and Humidity

Wasabia japonica requires continuous water supplied to its root zone. It’s a great plant to be grown in an area with a water feature or containers that allow the soil to remain continuously moist, more so than other plants. A majority of gardeners outside the Pacific northwest plant them in pots due to this reason. Their fragile nature demands specialized attention throughout their lives.

Wasabi is not drought-resistant. It is essential to provide continuous sources of moisture if you intend to harvest wasabi. Due to the conditions that it grew in, you should strive to replicate the humidity range of 90 to 95 percent.


Wasabi isn’t grown in traditional pots and soil. To be able to grow wasabi you’ll require an extremely well-drained growing medium like vermiculite, gravel, sand or you could even go down the aquaponics method.

It is possible to grow it in the tatamishi plant system mentioned above or directly into the gravel in a stream or a mixture of gravel and sand in containers for growing wasabi. Due to the difficulties of cultivating this particular plant, it’s better to experiment with a variety of techniques at once and determine which one is the best fit for your specific growing wasabi area.


Wasabi doesn’t require much fertilizer. They’re slow to grow and therefore, won’t absorb overly much fertilizer. It’s best to use the right amount of fertilizer (meaning that the NPK numbers are the same) such as a 12-12-12 at when you transplant. Many farmers also apply a foliar spray on the leaves around 1-3 months before harvest to increase the flavor.


Although it is difficult to cultivate from seeds, it’s feasible. They are known due to their insignificant germination rate however if you do happen to collect some seeds and seed shells attempt to overplant them and anticipate seeing a low rate of germination. In addition, if they’ve not been stratified yet in the past, you’ll need to place the wasabi seeds of wasabi in the refrigerator for two months to simulate a colder period for the wasabi seeds to rest. It is possible to expect three to four weeks for germination.

It is more likely that you’ll be able to get pups or pups from sources as well as plantlets or even starts (all the same similar). They are baby plants that are growing around the crown or stem of a mature wasabi plant. When you have these plants, you can directly place them in your growing medium to ensure that the wasabi root has enough space to develop downwards. This can be best performed in the fall, with many months of perfect growth conditions visible on the horizon.

Additionally, by the process of tissue cultivation, this choice is accessible to many farmers on a large scale who wish to produce sterilized food items at a much faster pace without spreading various diseases prevalent in the crop. This is a new method to propagate plants and isn’t something that can be replicated outside of a lab. When you’re looking for wasabi, search for plants that were cultured using wasabi If you’re unable to find the more conventional start.

Harvesting Wasabi Harvest and Storing

The most enjoyable aspect of growing wasabi is to reap the benefits of your work!

Harvesting Wasabi & Storing

Wasabi is edible throughout its existence. It is taken when its stalks protrude from the ground by 4 inches and are approximately one-half” thick. Simply remove the stalk with the care of the ground and try not to split it in two. Take the leaves off and remove any rot on the bottom of the plant.

It’s best to use it fresh and eaten raw after having it crushed or cooked (sautéed, soups, added to mashed potatoes, etc.). It generally lasts around two months in the refrigerator. It can also be dried and then powdered, however, this can cause the plant to go through a loss of nutrients. There are no unused portions of wasabi, as the entire plant is edible. Consider adding its stems and leaves into salads, or even making azuke using them as a pickle.


It is a difficult plant to grow you may come across a few issues during the two or more years you have been growing wasabi.

Problems in Growing Wasabi

One of the main issues that arise from growing wasabi is that it can be difficult to identify root rot. To fight this issue, look for starters that are resistant to rot. There are a variety of kinds that are developed to resist rots. Improve the drainage in your region and eliminate dead leaves that could carry diseases once they are dead and decaying.


Wasabi isn’t afflicted by numerous pest issues. It is more prone to fungal issues. But, aphids are enthusiastic about Wasabi leaves. Insecticidal soaps will be able to handle the aphids with ease.


Wasabi suffers from a myriad of fungal ailments, such as leaf spot and root rot, as well as petiole blight, and rhizome-based rot. It is sometimes difficult to distinguish between the various conditions as many have similar symptoms, such as dying leaves, browning, and root stalks that are blackening with a greyish hue on their leaf.

Preventing the disease is the best route to follow as only some plants do not can withstand the disease, especially considering the time it takes to pick. Apply a copper spray as an anti-spot treatment for leaf spots.

Frequently Asked Questions

1. Why is wasabi the hardest plant to grow?

Growing wasabi plants is frankly difficult because their growing needs are so specific. Wasabi requires shady conditions, uniformly moist but not wet soil, and temperatures between 45 and 75 degrees Fahrenheit without a lot of temperature swings.

2. What is the time it will take to develop Wasabi?

The rhizomes take about 2 years to mature at which time the entire plant is lifted, the main root harvested and the offsets replanted as your next crop; harvest time can be either spring or early fall. Wasabi roots can be kept in the fridge in a ziplock bag for up to several months, as long as they are intact

3. Does it make sense to increase the amount of Wasabi?

Yes. It’s rewarding when you get your abundance!

4. Can I grow wasabi indoors?

If you live in a region, where the temperature fluctuates a lot and it’s cold or hot, the place to grow wasabi is indoors. A basement, or near a North or East facing window is the best place.

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