Wasabi is widely acknowledged as one of the most difficult plants to cultivate. It requires a humid, temperate environment, takes two years to develop, and is especially susceptible to illness when grown in large quantities.
Growing wasabi is worth the effort because it has an unparalleled flavour that is hot, fresh, and sweet, along with a plethora of health benefits. Should you be willing to take on the effort, it is possible to cultivate wasabi by replicating its natural growth environment.
Wasabi Overview
| Botanical Name | Wasabia japonica |
| Common Name | Wasabi, Japanese horseradish |
| Plant Type | Perennial vegetable |
| Size | 24 inches tall |
| Sun Exposure | Full shade |
| Soil Type | Moist, rich, well-drained |
| Soil pH | 6.0–7.0 |
| Hardiness Zones | 8–10 (USDA) |
Planting Wasabi Plants
If you are starting from plantlets—small growths on the rhizome of a larger wasabi plant—it is best to start your wasabi plants in the autumn. Wasabi grows most during the cold season, which spans from October to spring, because the temperature is lower and there is a greater likelihood that the plants will receive regular watering
In this type of setup, it is easier to maintain the ideal growing conditions for wasabi because less gravel, sand, or draining medium is needed. Furthermore, farmers will either cover their newly planted plants with shade cloth or place them in a fully shaded greenhouse.
When growing wasabi in the ground, transplant plantlets into containers that are deeper than typical, at least 2 inches deep, due to their lengthy roots. Compared to other roots, this one needs more room to grow.
Wasabi Plant Care
Wasabi plants are among the hardest plants to grow; therefore, cultivating one might be challenging. However, with sufficient time and proper cultivation, one rhizome can produce a significantly bigger harvest. This is an edible rhizome that requires highly specific care; a gardener should attempt to mimic those circumstances as closely as possible.
Sun and Temperature
Mild weather is ideal for the wasabi plant to flourish. Wasabi leaves require a temperature range of 46 to 70 degrees Fahrenheit and a shaded spot with no direct sunshine. Wasabi plants can freeze at around 27 degrees Fahrenheit and can die at temperatures above 80.
Try creating shade in the shape of a huge tree shade or shade cloth to replicate these conditions. Ten inches of compost added to your planting medium will supply nutrients and protect the roots from severe temperature swings.
Water and Humidity
Water must be continuously provided to the root zone of Wasabia japonica. Because it can endure considerably wetter soil than many other plants, it is the perfect plant to cultivate in a water garden or containers. Because they are erratic and require constant care, many gardeners outside of the Pacific Northwest grow them in pots.
The wasabi plant is incapable of withstanding drought. If you want to harvest wasabi, you’ll need a reliable source of moisture. It would be best to try to replicate a humidity level of between 90 and 95%, given the growing conditions it evolved under.
Soil
In standard potting soil, a wasabi plant is not grown. Choose a growth medium that drains extremely well, such as gravel, sand, or vermiculite, or even attempt aquaponics if you want to cultivate wasabi. Six to seven pH is ideal for soil.
Growth in a 50/50 mixture of sand and gravel in growth containers, straight into gravel along a stream, or in the tatami system previously mentioned are all viable options. It could be advisable to experiment with several growing techniques at once to see which works best for your growing conditions, considering how challenging it is to cultivate this specific plant.
Fertilizing Wasabi Plants
Your wasabi plant doesn’t require fertilizer. They can’t tolerate too much fertilizer because they grow slowly. It is advised to use a balanced fertilizer, like a 12-12-12 when transplanting because it guarantees that all of the NPK values are the same. Many producers also spray foliar one to three months before harvest to improve flavour.
Propagating Wasabi
Though most people just buy new transplants once the old plants are fully harvested, wasabi can theoretically be propagated from seed or offshoots. If propagation is something you want to try, cut off a few little branches that emerge from the base of an established plant and place the cuttings in a 50:50 mixture of sand and compost.
They should have enough roots growing to be moved into pots or the garden in about two months. Wasabi seeds are hard to find, even from commercial merchants, because they are tough to germinate.
Harvesting and Storing Wasabi
Reaping the rewards of your hard work is the simplest part of expanding!
Harvesting
Wasabi may indeed be consumed almost year-round. That being said, it is often harvested at 4-5 inches and 1 1/2 inches above ground. To prevent it from splitting in two, pick up the stem from the ground and draw it out slowly. Remove the degeneration near the base of the root and the foliage.
Storing
It tastes best served raw, grated, and fresh. When used fresh, within two months of storage, it is usually at its optimum. It can also be dried and powdered, although this process depletes the plant of several vital nutrients. Since the entire plant is edible, wasabi produces no waste. Use the leaves and stems for pickling or tossing in a salad (auk).
Common Pests and Plant Diseases
Numerous pests could be causing problems for your wasabi plants. As a member of the Brassica family, wasabi is favoured by parasites such as cabbage worms, which also enjoy eating broccoli and cabbage. Slugs must be removed by hand, although aphids can be eliminated with a gentle cloth or by frequently misting water on them.
Areas that are kept cool and shaded will repel bugs. Using insecticidal soaps while using wasabi is not advised. One may use copper spray or baking soda spray if a fungal infection is present.
FAQ
What’s the duration needed for Wasabi to grow?
It usually takes two years for wasabi to reach harvestable maturity.
Is it possible to grow wasabi in the US?
In the US, it is possible to grow wasabi using seeds or plant starts, but since real wasabi seeds have different labels, it is best to use plant starts. Plant beginnings might be difficult to come by outside of Japan.
What’s the trick to cultivating wasabi?
The secret to growing wasabi yourself is to meet its very specific growing requirements. It prefers a very specific temperature range with high humidity and struggles in direct sunlight.