Wasabi, often known as "Japanese horseradish," is the emerald jewel of Asian cuisine, prized for its pungent flavour and culinary versatility. Wasabia japonica, is notoriously challenging to grow and rarely encountered in its fresh from outside of Japan.
However, with the right knowledge and care, cultivating wasabi at home can be a rewarding venture that delivers a continuous supply of this flavourful root. I have been cultivating Wasabi in the UK for ten years and learnt much about this interesting plant. I have to confess I personally grow it more for the edible leaves and stems than the root itself!
In this thorough guide, we'll walk you through each step of the wasabi-growing process, from selecting the right cultivar and preparing the ideal growing conditions to harvesting the final product. Whether you're a culinary enthusiast, an adventurous gardener, or a commercial grower interested in adding this valuable crop to your portfolio, you'll find the insights you need to succeed here.
However, with the right knowledge and care, cultivating wasabi at home can be a rewarding venture that delivers a continuous supply of this flavourful root. I have been cultivating Wasabi in the UK for ten years and learnt much about this interesting plant. I have to confess I personally grow it more for the edible leaves and stems than the root itself!
In this thorough guide, we'll walk you through each step of the wasabi-growing process, from selecting the right cultivar and preparing the ideal growing conditions to harvesting the final product. Whether you're a culinary enthusiast, an adventurous gardener, or a commercial grower interested in adding this valuable crop to your portfolio, you'll find the insights you need to succeed here.
Understanding Wasabi
Before we dig into the details of growing wasabi, it's vital to understand the intricacies of this unique plant. Wasabi belongs to the Brassicaceae family, which includes other well-known edibles such as mustard, cabbage, and horseradish.
Originating in Japan, it thrives in cool, shady, and moist environments, which is why traditional wasabi farms are often found in the mountainous regions of Japan.
Wasabi is a rhizomatous perennial, meaning it grows from an underground stem called a rhizome. It's sensitive to both temperature and light, features that significantly impact its growth and flavour. The delicate balance of these conditions is crucial for obtaining the fresh pungency of wasabi.
Originating in Japan, it thrives in cool, shady, and moist environments, which is why traditional wasabi farms are often found in the mountainous regions of Japan.
Wasabi is a rhizomatous perennial, meaning it grows from an underground stem called a rhizome. It's sensitive to both temperature and light, features that significantly impact its growth and flavour. The delicate balance of these conditions is crucial for obtaining the fresh pungency of wasabi.
Choosing Your Cultivar
Selecting the right cultivar is the first and most critical step in your wasabi-growing journey. Cultivar selection can influence growing conditions and the eventual flavour and yield of your wasabi. Some popular cultivars include:
Daruma
With larger leaves and a higher percentage of rhizome, Daruma is known for its strong flavour. It's ideal for those who want to focus on the rhizomatous part of wasabi—the part most commonly used in cooking.
Mazuma
Mazuma is favored for its high leaf-to-rhizome ratio. It provides a milder flavor and is great for those who aim to use the entire plant in their culinary adventures.
Others
There are many other cultivars to consider, each with its own unique characteristics. Do your research, and talk to local suppliers or experienced growers to find the best match for your growing goals.
Daruma
With larger leaves and a higher percentage of rhizome, Daruma is known for its strong flavour. It's ideal for those who want to focus on the rhizomatous part of wasabi—the part most commonly used in cooking.
Mazuma
Mazuma is favored for its high leaf-to-rhizome ratio. It provides a milder flavor and is great for those who aim to use the entire plant in their culinary adventures.
Others
There are many other cultivars to consider, each with its own unique characteristics. Do your research, and talk to local suppliers or experienced growers to find the best match for your growing goals.
Setting Up the Growing Environment
Setting up your growing environment is one of the most crucial parts of growing Wasabi. In this section we will cover how to get the perfect growing environment for this novelty crop. Below I have included my video guide of how to grow Wasabi at home!
Soil and pH
Wasabi demands a particular type of soil: loose, stony, and well-draining, with a pH between 6.0 and 6.7. A high organic matter content is important, but too much can lead to root rot, a common issue with wasabi. Mixing sand and fine gravel with your soil helps it retain moisture without becoming waterlogged.
Temperature and Light
Consistency is key when it comes to temperature and light conditions. Wasabi thrives in cool temperatures, ideally between 45°F and 70°F (7°C to 21°C). Shade is crucial—direct sunlight can scorch the leaves and adversely affect the rhizomes' flavor, turning them bitter. I have found some dabbled sunlight is ok to mimic its natural forest range.
Watering
Wasabi is a water-loving plant. The soil should be kept consistently moist, but never waterlogged. Over-watering is a major cause of root rot, which is often fatal to the wasabi plant.
Humidity
Humidity is a much underrated factor in successful Wasabi growing! I only started seeing success growing wasabi when I planted some in a shady corner of my polytunnel. It is important the air has a high moisture content to mimic the humid environments of Japanese mountain valleys. As well as humidity keep your growing areas sheltered from harsh winds.
Container Growing
For small-scale or indoor cultivation, growing wasabi in containers is the most practical approach.
Containers should be shallow but wide to accommodate the shallow root system of wasabi. Choose a pot that's at least 12 inches in diameter and 6 inches deep, with plenty of drainage holes.
Layer the bottom of the pot with gravel to aid drainage, and fill it with the well-draining, acidic soil mix discussed earlier. Remember to place the container in a shady area and ensure it's protected from temperature extremes.
Containers should be shallow but wide to accommodate the shallow root system of wasabi. Choose a pot that's at least 12 inches in diameter and 6 inches deep, with plenty of drainage holes.
Layer the bottom of the pot with gravel to aid drainage, and fill it with the well-draining, acidic soil mix discussed earlier. Remember to place the container in a shady area and ensure it's protected from temperature extremes.
Planting Wasabi
Now that you've prepared the perfect planting area, it's time to plant your wasabi. Here's how to do it:
Seed vs. Plant division
Wasabi can be grown from seed or plantlets. Seeds are more cost-effective, but they can be more challenging and take longer to germinate. Plant divisions provide a head start and are generally more reliable. These can be purchased online or from a local supplier. Once you have grown a robust wasabi plant you can harvest your own plantlets and divide your stock.
Depth and Spacing
Plant your wasabi with the crown (the dividing line between the roots and the tops) just above the soil. If you're planting multiple wasabi plants, space them at least 12 inches apart to allow for their lateral spread.
Mulching
After planting, mulch the soil around the base of the plant with straw, coconut coir, or organic mulch. This helps retain moisture and maintain a cool soil temperature.
Seed vs. Plant division
Wasabi can be grown from seed or plantlets. Seeds are more cost-effective, but they can be more challenging and take longer to germinate. Plant divisions provide a head start and are generally more reliable. These can be purchased online or from a local supplier. Once you have grown a robust wasabi plant you can harvest your own plantlets and divide your stock.
Depth and Spacing
Plant your wasabi with the crown (the dividing line between the roots and the tops) just above the soil. If you're planting multiple wasabi plants, space them at least 12 inches apart to allow for their lateral spread.
Mulching
After planting, mulch the soil around the base of the plant with straw, coconut coir, or organic mulch. This helps retain moisture and maintain a cool soil temperature.
Caring for Your Wasabi Plant
Fertilizing
Wasabi is not a heavy feeder, and it's essential to avoid over-fertilizing, as this can impact the flavour. A balanced, water-soluble fertilizer with low nitrogen content, applied at half strength every two weeks, is a good starting point.
Pruning
Keeping an eye on the plant’s growth is essential. Regular pruning promotes airflow and prevents any one part of the plant from becoming too dense which can lead to disease. Remove any flowering stalks that appear, as they indicate stress on the plant and divert energy from rhizome and leaf growth. I try to thin out the leaves as much as possible because they are delicious!
Pests and Diseases
Wasabi's natural pungency acts as a deterrent to many pests, but it can still be susceptible to aphids, slugs, and snails. Slugs and snails absolutely love them! Monitor your plants regularly and take swift action if you notice any infestations.
Root rot and leaf spot are the most common diseases associated with wasabi. To prevent these, ensure proper drainage, provide good air circulation, and avoid stagnant water.
Wasabi is not a heavy feeder, and it's essential to avoid over-fertilizing, as this can impact the flavour. A balanced, water-soluble fertilizer with low nitrogen content, applied at half strength every two weeks, is a good starting point.
Pruning
Keeping an eye on the plant’s growth is essential. Regular pruning promotes airflow and prevents any one part of the plant from becoming too dense which can lead to disease. Remove any flowering stalks that appear, as they indicate stress on the plant and divert energy from rhizome and leaf growth. I try to thin out the leaves as much as possible because they are delicious!
Pests and Diseases
Wasabi's natural pungency acts as a deterrent to many pests, but it can still be susceptible to aphids, slugs, and snails. Slugs and snails absolutely love them! Monitor your plants regularly and take swift action if you notice any infestations.
Root rot and leaf spot are the most common diseases associated with wasabi. To prevent these, ensure proper drainage, provide good air circulation, and avoid stagnant water.
Harvesting Your Wasabi
Harvesting is the most exciting part of your wasabi-growing adventure. It's the culmination of all the hard work and attention you've lavished on your stock.
Timing
Wasabi can be harvested from about a year after planting, but optimal flavour and yield are generally achieved after two years. The leaves can be harvested at any time, but for the best rhizomes, plan to harvest in the fall or winter when the plant’s energy is focused on the roots.
Technique
Carefully dig around the rhizome, loosening the soil as gently as possible. Lift the entire plant, shake off the soil, and cut the rhizome from the crown. The rhizome can be eaten fresh or grated just before consumption to fully release its pungency.
Remember, harvesting the rhizome kills the plant. If you continue to grow from plant divisions or the crown, you'll maintain a continuous supply of fresh wasabi.
Final Thoughts
Growing wasabi is a unique and rewarding experience. Just as the perfect balance of cool, moist, and shady growing conditions is necessary for wasabi, your balanced care and attention to detail will be vital to your plant's success. Whether you're an aspiring horticulturist or a dedicated chef, the art of cultivating wasabi can open new culinary doors and lead to a deeper appreciation of Japan’s cultural and culinary traditions.
Please share your wasabi-growing adventures with us and continue learning and improving your techniques. Above all, savour the special flavour of home-grown wasabi, and perhaps you’ll get a taste of why this plant is so highly revered. Remember, with patience and persistence, anyone can master the art of growing this cherished delicacy.
Why not watch my video below where we do a taste test between real Wasabi verses fake.
Please share your wasabi-growing adventures with us and continue learning and improving your techniques. Above all, savour the special flavour of home-grown wasabi, and perhaps you’ll get a taste of why this plant is so highly revered. Remember, with patience and persistence, anyone can master the art of growing this cherished delicacy.
Why not watch my video below where we do a taste test between real Wasabi verses fake.
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