You Can Grow Wasabi in Pots
One option that is very successful for growing wasabi is to plant your wasabi starts in 1 to 2 gallon pots with good potting soil. Doing this gives you flexibility for when the weather turns too cold or too hot. When that happen happens simply bring your wasabi plant indoors.
So what is too hot or too cold? Glad you asked! See immediately below for that answer!
What Parts of the United States Can You Grow Wasabi In?
Wasabi can and does grow all over the United States!
What you need to watch out for is weather that is too either too hot or too cold.
If the weather gets over 80 degrees or under 32 degrees - simply bring your pots inside and keep them out of direct sunlight.
If the weather is going to be over 80 degrees for just a few days and then go back to being under 80 degrees, you can leave the plants outside as they can handle warmer weather for a couple of days.
The Myth of Wasabi Seeds
Sadly, many of the wasabi seeds that are sold today (especially online) are not real wasabi i.e.
Wasabia japonica, they are actually mustard seeds or seeds for “wasabi” mustard for arugula or seeds for “wasabi” arugula.
Please note neither “wasabi” mustard or “wasabi” arugula is real wasabi. One is a variety of mustard and the other is a variety of arugula.
There is a reason that the largest reputable US seed companies don’t sell wasabi seeds on their own websites.
Wasabi seeds are very rare because they are very difficult to harvest.
You are much better off simply getting wasabi plant starts and growing those.