What water types are suitable for growing Wasabi?
Everyone takes water for granted – water is water – right?
Not really – there is drinkable water (potable) that we get out of a tap after treatment, and there is non-potable water which is not suitable for drinking, such as household waste water and stagnant untreated pond water.
The rule about what water type to use is really simple. If you can’t drink the water without getting ill or poisoned then you can’t use it for growing wasabi. There are other restrictions as well such as no herbicide or pesticide or other chemical contamination that must be complied with as well.
We will look at the suitability of the water types we normally have access to for growing wasabi.
- Pond water – this is not normally suitable unless the water has been filtered to remove the physical particles and sterilised to kill any bacterial or microbial loading in the water. At the end of this treatment the water MUST reach or exceed the potable water standards for drinking water. Most ponds are contaminated with animal feces and have a number of different types of creatures living in it. All this must be removed.
- River or stream water – at the very minimum the water will need to be filtered and sterilised. In this case there might also be a requirement to remove suspended particles in the water by the use of a settling tank. Using this type of water normally involves bureaucracy of some sort to get the appropriate licenses and permissions – this is especially true if you want to return the water to the original river or stream.
- Bore water – this is a common means of supplying water in most agricultural communities. A lot of water in this category will have either some salinity or excess chemicals in it. We would suggest that if the water has any indication of salinity (salt) in it then you do not use it for growing wasabi plants as all. Find another water source. The chemicals in this water type are commonly metallic in nature such as iron and magnesium – they must be removed before being used for growing wasabi. Another common chemical is calcium which causes deposits inside pipes. Some of this needs to be removed if necessary. Some types of bore water are also warm to hot and if that is the case then it cannot be used to grow wasabi. Water of this type needs to be carefully filtered to remove any particles carried in the water flow – this is very common and the term normally used for this is turbidity.
- Spring water – this is bore water that has managed to find its own way to the surface. In this traveling the water is likely to have picked up a large amount of dissolved chemicals. A water test from a licensed and approved water laboratory will be necessary to check suitability, and in addition will need to test for surface contamination from animals or humans.
- Tap water or town treated water – in most places of the world the water from the tap is drinkable, whereas in others it is not. However, most water of this type is treated with chlorine as a steriliser, and sometimes with fluoride. Because of this it is recommended that if you going to use this type of water you dechlorinate the water and remove the fluoride before using it on the wasabi plants.
- Rain water – this is the best type of water to use. It still needs to be filtered and sterilised, but is unlikely to need much else doing to it. This will require a collection tank (cistern) to hold the rain water before it is introduced into the growing system. The size of the holding tank would be dependent on a number of factors such as amount and frequency of the rain and the size of the growing area.
As you can see – water varies significantly. Get it tested initially and then on a regular basis by an approved Water laboratory to make sure it stays within the growing parameters set by the wasabi plant.