Wasabi (Japanese radish) is considered by many to be one of the most difficult plants to grow. It requires a humid environment at a moderate temperature and is very sensitive to disease when grown in large quantities. The reward, however, far outweighs the difficulties, as it brings numerous health benefits and has a distinctive fresh, spicy and sweet flavor that cannot be matched. If you want to face this challenge, know that you can grow wasabi by simulating the natural environmental conditions in which this plant grows best.
Steps
Part 1 of 3: Creating the Ideal Conditions
Step 1. Look for a humid and temperate environment
Wasabi is native to Japan and grows best in a humid warm climate, between 8 ° C and 21 ° C. It is a notoriously demanding plant and does not grow in places where the temperature rises or falls too far beyond this range.
- Wasabi grows spontaneously in humid wooded areas, with good air humidity and well-draining soil.
- In the United States, for example, the best conditions to grow it are in the Pacific Northwest and the Blue Ridge Mountains in the east, but there are other places in the world that are naturally suitable for growing the plant.
Step 2. Consider finding solutions to control the temperature
If you live in a region that does not have the natural climate suitable for growing wasabi, you need to artificially recreate the right conditions. One of the best ways to do this is to use a greenhouse that traps heat, humidity and allows you to manage the temperature as you wish. If you choose this solution, set the weather conditions so that the temperature is always between 8 ° C and 21 ° C.
If you live in an environment with optimal conditions, you can grow wasabi without the need for a greenhouse. If your region has a warm climate, use a tarp or sheet to shade the base of the plant so it doesn't get too hot. If the environment in which you live provides for rather mild cold periods, cover the plant when the temperature drops
Step 3. Choose a well-shaded spot
Wasabi does not thrive well in direct sunlight; it needs a place very sheltered from the sun. In nature, it grows under dense forests, where sunlight filters through the leaves in sufficient quantity to give the plant what it needs to thrive. To be able to grow it at home, try to recreate this environment by planting wasabi under trees or recreating an artificial environment protected from the sun.
In a greenhouse, this aspect should not be overlooked and you must make sure that the wasabi has all the shade it needs. Place it under taller plants or near shaded windows to make sure it doesn't get in direct sunlight
Step 4. Fix the soil with compost
Use a mixture of organic and sulfur-rich fertilizer. Plant it to a depth of 25 cm and mix the top layer of soil to create a rich and healthy soil. The goal is to reach a pH between 6 and 7. This is the ideal pH for wasabi. You need to get rich, organic soil with the right pH to give the plant the best chance of survival in a home environment.
Step 5. Make sure the soil is well draining
Wasabi thrives in a humid environment, as mentioned, but doesn't like muddy, soggy soil. To check if the soil is draining properly, water the area and check the soil absorption time. If you see that the drainage process is slow, you need to add more compost. If it drains immediately, the soil is suitable for growing this plant.
- It is a good idea to plant wasabi near a natural pond or stream, as the soil in these areas remains constantly moist but, at the same time, drains well naturally.
- You can also decide to plant it near a waterfall that continually sprays the plant to provide it with water.
Part 2 of 3: Plant Wasabi and Take Care of It
Step 1. Sort the seeds in late fall
Wasabi seeds are hard to find in local nurseries, so many people buy them online. Late autumn is the best time to sort them, so that the seeds can create good roots during the winter. When you can get them, keep them moist and plan to plant them within 48 hours of receiving them.
Step 2. Plant the seeds
The night before planting, place them in a small bowl and cover them with distilled water. Leave them to soak overnight. During this time the shells soften, in order to facilitate the germination process. Plant them in the soil to a depth of about 2.5-5 cm by pressing them lightly.
Step 3. Keep the soil and seedling moist
Wasabi is a semi-aquatic plant, which must be kept moist to flower. Every day he sprays the soil and sprouting seeds with a fresh water spray to simulate the splashes of water that come from natural sources, such as a river or waterfall. If the wasabi dries, it begins to wilt.
- Although the plant must always be moist, it must not remain soaking in water. Do not pour whole buckets of water on the wasabi, but mist and spray water one or more times a day (especially when the weather is hot and dry) to keep it always wet.
- Since it must always be kept moist, this plant is susceptible to mold and disease. If you notice that a seedling gets sick (wilting or losing color), remove it from the ground immediately to prevent it from infecting other plants.
Step 4. Remove the weeds
Eliminate weeds so the wasabi roots have plenty of room to grow. Since the soil is kept moist every day, weeds tend to sprout quickly. Tearing them off daily or every other day will allow you to keep the problem under control.
Part 3 of 3: Collecting and Using Wasabi
Step 1. Take care of the plants for at least two years before harvest
Wasabi does not develop its distinctive flavor until it becomes ripe after about 24 months. During this period it grows about 60 cm in height and 60 cm in width. Then it stops growing and begins to focus all energy on developing the carrot-like rhizomes under the soil.
Step 2. Collect the ripe rhizomes
They become ripe and ready to eat when they reach the length of 18-20 cm. Pick one up to check its length before completing the entire crop. Use a long, thin spade or pitchfork and be careful not to cut the rhizomes when digging into the ground.
Step 3. Leave some plants in the ground for self-seeding
The wasabi left in the soil will produce new seeds that will fall into the soil, saving you the trouble of ordering more. Leave several plants behind so you can have a new crop for at least another couple of years.
When the new plants begin to sprout, spacer them about 30 cm from each other, so that they have plenty of space to grow. If you leave them too close, many could wither and die
Step 4. Use wasabi
Clean the rhizomes and discard the leaves. To appreciate its fresh pungent flavor, cut only the necessary amount and leave the rest of the rhizome intact. The spiciness will wear off after a couple of hours, so it's best to only cut as much as you need to prepare one meal at a time.
Step 5. Save the wasabi for later use
You can keep it fresh in the refrigerator for about a month or two before it starts to rot. If you want to keep it for later use, you should dry it and grind it to make a powder. The powder can then be mixed with a little water to form a paste.
Advice
- The seeds must be kept moist (keep them in the fridge). If they are dry, they hardly develop into a seedling.
- Wasabi prefers a very humid environment and does not grow well in a dry and very hot climate. You may need to continue spraying it if the weather is very hot.
- If the soil is clayey, add some lime and compost.
- It may be difficult to get the seeds; look for a farmer or a grower who can kindly give you some. Alternatively, go to a Chinese or Japanese grocery store and ask them if they can provide you with the seeds or seedlings.
Warnings
- Black-rot (black vine rot) can threaten wasabi plants; be careful not to leave yours in waterlogged soil.
- Aphids like wasabi. Treat them with a spray pesticide product.
- Know that the leaves and stems (petioles) are fragile. If they break or are disturbed in any way they can slow down and stop growth.
- Cats can be attracted to the leaves of this plant.
- Wasabi is prone to snail infestations, especially in the early stages of growth. Do treatments and remove them if necessary.
