I’m Growing Wasabi!

I was walking through Armstrong Nursery about a month ago, and succumbed to an impulse buy. Honestly, this isn’t a rare occurrence for me. That day in particular, I was only at the nursery to purchase some bags of potting soil, but then my eye spotted a very lush plant in the edible/vegetable section of the nursery—wasabi! Today I want to share why I want to try growing wasabi and what I’ve learned so far.

Here’s the thing, I use wasabi at home almost never. Yes, we do enjoy wasabi with our sushi at restaurants, but it’s truthfully a food we don’t personally use very often. In fact, I seriously questioned whether I should be dropping $40 on a potted wasabi plant at the time. In my head, I’m like ‘this could buy me almost seven chai lattes….’ (it’s an old habit from my college days when I basically budgeted everything around being able to buy coffee or tea for myself). Anyway, my plant-loving mind won out, and I brought home this lovely specimen of japanese wasabi to care for.

Interesting Wasabi Facts

Wasabi (wasabia japonica) grows naturally along mountain rivers and streams in Japan. It’s a plant that is cultivated mostly for it’s root, which is ground into a paste to be used as a condiment with food. You’ve probably seen it alongside your sushi.

I was fascinated to learn that wasabi is related to another plant I grow in my garden—horseradish! Both plants are in the brassicaceae family (yep, related to mustards and such) and share a spicy, pungent flavor. In fact, as wasabi became more popular around the world, cheap versions of “wasabi” paste started to emerge. Unfortunately these cheaper versions contain no actual wasabi at all—they are horseardish mixed with green colorants. This is a huge reason I wanted to learn about growing my own wasabi, as I’d love to  taste the real thing, and also learn about using other parts of the plant as well.

I talk more about this below, but the entire wasabi plant is edible! Apparently the leaves and stems are used in various ways in Japan. Because many of us don’t have access to fresh wasabi plants, it’s more difficult to experience these types of dishes where we are. That’s one thing I love about growing my own food—it encourages exploration. We are more likely to be motivated to try things when they are staring us in the face—-when we have put effort into nurturing and caring for something—and don’t want to waste it.

Getting Started Growing Real Wasabi

Over the years, I have witnessed fellow gardeners attempt to grow wasabi here in Southern California. They always started with a rhizome (what looks like a ginger root) and potted it up like I pot up my dahlia tubers. Many of my fellow gardeners struggled with this plant, and so I kind of have it in my head that I’ll probably have trouble too. Regardless, I’m the type of gardener that wants to “see for myself.”

The wasabi plant I purchased was a luscious, green, verdant mound in a one gallon pot. Personally, I was super excited to not have to start with a rhizome (as that comes with a different set of complications). At the nursery, they were actually keeping the wasabi plants under the shade cover. Supposedly, wasabi is a shade-loving plant, which is so refreshing! As gardeners, I feel like finding shade-loving edible plants can be a challenge.

According to various sources, there are actually many different cultivars of Japanese wasabi. For example, the most common cultivars are daruma and mazuma wasabi. Unfortunately, the label on the pot did not specify what variety of wasabi I’m growing.

Watch Out for Pests

I was surprised to learn that wasabi is in the brassica family. I was even more surprised when I spied cabbage caterillars feasting on my leaves! Honestly, I should have put two and two together, but now I know that the same pests that like my cabbage and kale will also snack on my wasabi. In the photo below, you can see some evidence of cabbage caterpillars on the wasabi leaves. I simply picked these caterpillars off, but there are a myriad of other approaches you can try for cabbage caterpillars that I discuss in this blogpost. 

Conditions for Growing Wasabi

Once I got home, I googled a bit about growing wasabi. One great source was The Wasabi Store, a store that sells wasabi on the Oregon coast. According to their website, the entire wasabi plant is edible! The leaves and stems can be harvested and eaten. But be careful, the leaves are slightly spicy, like arugula, and the stems are said to be even hotter.

Wasabi is pretty cold tolerant, although it likes temperatures between 45 to 75 degrees F. Of course, “cold” is relative, but the farm in Oregon states that their plants in Portland experienced multiple days of below freezing temperatures, and ninety five percent survived! As you might know, the lowest temperature we tend to get here in zone 10 is about thirty degrees fahrenheit, but it’s our heat that is more of a concern to me. Also, it’s important to note that the Oregon website only sells the daruma cultivar of wasabi, so that could also be a factor in the cold tolerance I imagine.

Wasabi also likes moisture. This plant thrives near rivers and streams and needs lots of moisture to be happy. Shortly after purchasing my wasabi and transplanting it into a pot, we had to leave our home for almost two weeks! In preparation for our vacation, we set everything up with automatic irrigation. We use a b-hyve smart indoor/outdoor wifi sprinkler controller that lets us program each garden zone based on what’s growing there. I love it! Since I was new to growing wasabi, Sam guessed it’s approximate water needs as he was programming the irrigation. Well, apparently Sam guessed perfectly, because 11 days later our wasabi had started to sprout new growth and was looking happier than ever! We lucked out. He added a 2gph flag emitter for the wasabi and it ran at 4am, 5am, and 6am for five minutes every other day. Keep in mind, this was during a heatwave for our area. When it’s colder, we water less.

Can I Grow Wasabi in a Pot?

Yes, and this is my plan. Currently, my wasabi plant is growing in a pot on my patio. When I got home, I simply up-potted my wasabi into a slightly larger pot with some organic potting mix. While I’ve read that wasabi likes a slightly acidic soil, I didn’t have any acid pottinig mix, so it was planted with regular ole potting mix.

Wasabi Needs Perfect Conditions

Here’s the thing. Take everything here with a grain of salt. It’s been said that wasabi will only form a useable root under perfect conditions. Perfect. So, while my plant may produce leaves, I don’t have proof that it’s forming a root yet. Sometimes it can take 2-3 years to have a harvest of wasabi root.

And that concludes my little story about growing wasabi at home. So far, it’s going well, and I can keep you all up to date as we learn more about harvesting and processing this really amazing plant!