Water nutrients for your wasabi crop.
The amount of water nutrients that you run past and through the roots of your wasabi plants will depend on the growing method you are using.
If you are growing the wasabi in the ground, and the ground has been prepared properly with the correct level and type of fertilisers, then the water will act as a dissolving agent to get those nutrients to the wasabi roots. Even doing this requires that a water analysis has been done by an approved water testing laboratory. It is this result together with the soil analysis that will allow the fertiliser expert to determine what and how much of each type of product needs to be added to the soil to make it perfect for the wasabi plant.
This information can be found in the Wasabi Growing Primer, which is available here.
If you want to grow wasabi in water, river or stream or hydroponically, then the level of water nutrients becomes even more important.
In Japan and China/Taiwan it is not uncommon to find that wasabi growers will put bags of blood and bone, or chicken feces upstream from the water and apply fertiliser in this way. It is a bit hit and miss, but seems to do the job. The problem with this method is that the people downstream from the wasabi farm also get a dose of sometimes unwanted fertiliser in their water supply. This is a problem if that water is to be used for drinking. Pollution or adding fertiliser like this to water courses may not be allowed where you live, so find out before you do this. 🙂
If you are using a closed or run to waste system then you can check the water nutrient levels before hand and adjust it accordingly using a fertiliser injection system. These are readily available in the hydroponic growing shops, and work really well. If you are going to use this method then I would suggest using the closed or reticulation method in order to reduce the amount of nutrients you use.