Page 1 of 1

Water meters anyone?

Posted: November 8th, 2010, 12:12 pm
by soda
I picked up a basic water meter for $10 at bunnings due to the stress of being gifted a old JBP and finding it hard to tell how wet/dry it was. With my smaller bonsai's I generally go by surface feel and weight. This JBP always felt really heavy and I assumed it was holding water quite well.

The meter read otherwise, indicating it was much drier than all my other stock. However even since changing how much water I'm giving it, I am having trouble getting the needle to read anything but dry. It creeps up into the 'moist' range just. Confusingly, even on imersion the tree doesn't release any bubbles?

Is there any kinds of growing mediums that may give a false reading?

BTW the meter has been really good round the garden identifying drier areas.

Image

Re: Water meters anyone?

Posted: November 8th, 2010, 12:49 pm
by Ash
Hi Soda,

These types of water meters may not provide you with the information that you are looking for. They work on conductivity which means that different soils will give different readings. Coarse free drained organic soil will read as drier than a finer sandy soil with the same water content (measured by comparison of wet and dry weight). For almost ten years from 1996 to 2006 we ran experiments in high and low carbon dioxide glasshouses at CSIRO and we tried many types of soil moisture instruments both cheap and nasty and very expensive to help those who couldn't tell when to water and when to wait. We finally settled on using bamboo kebab skewers (replaced frequently because they stain and decay) and judged them by eye. The only way we could determine moisture content in a consistent way over the years was comparison of wet and dry from soil core harvests.

Have a crack at the simple skewer and see what it tells you.

best regards
Ash

Re: Water meters anyone?

Posted: November 8th, 2010, 1:03 pm
by soda
Thanks Ash, very helpfull! I was sure this trees was wet, but it constantly reads otherwise. Will take home some coffee stirrer sticks and give it a try.

Re: Water meters anyone?

Posted: November 8th, 2010, 3:24 pm
by craigw60
Black pines like to be kept pretty dry so don't over water it or the needles will get very long
Craigw