Increasing Water "Churn" in Self-Watering Containers

rnewste · August 30, 2009

I once thought is was a "good thing" to have a large water reservoir in the design of a Self-Watering container, but I now take the extreme opposite view today.

What I have found is that water held in a large reservoir can stagnate, become an easier home for mosquito breeding, and buildup of algae growth on the side-walls that are constantly under water:

The availability of the ingenious Automated Watering System from the EarthBox Company now permits "always on" level control so that you can precisely control the water depth to an eighth of an inch accuracy. The passive system is easily adaptable to homemade SWC units.

On the left, is the "stock" AWS unit as it comes from the EarthBox folks. It is quite simple to lengthen the sensor tube from the original 10", to what I use in the EarthTainer of 11.5". This keeps the water level in the 'Tainer to about 3.5" at all times.

But in an effort to minimize algae growth, etc. and more importantly, to have the reservoir water as "fresh" as possible at all times, I wanted to have kind of F.I.F.O (First-In-First-Out) system where water would be constantly "churning" at the very bottom of the 'Tainer. So what I've now done is to lengthen the sensor tube to 14" thus holding the water level at a constant 1".

Since the two tomato plants will consume one to two gallons per day in mid-season, water should cycle through the 'Tainer every 24 hours or so. I realize that as a liquid, I won't get 100% F.I.F.O. but it should provide fresher water to the plants with this approach. Of course, this significantly increases the frequency of watering that one would have to do manually, and the AWS makes this a "don't care" event.

The AWS unit cost on a per plant basis works out to be under $5.00 today (They are having a Sale on currently at the EarthBox site). I figure a 10 year service life, so at under 50 cents per year cost per plant, this system is a real bargain for the time savings, and peace of mind when away on vacation.

I suppose if one had a 'Tainer on a perfectly level surface, you could experiment with keeping the water level at one-quarter inch at all times using a 14.75" sensor tube - - but I'll stick with the constant one inch water level for now.

Ray

huntsman · September 3, 2009

Hey Ray!

Really glad I read this, as I will start building my first EarthTainer on the weekend.

I have the PDF you produced, but would like to know where I can find all of the amendments you have made over time?

Much obliged!

rnewste · September 3, 2009

Huntsman,

Send me an email at: RNEWSTEAD@AOL.COM and I will send you the latest .pdf Instruction Guide. BTW, I am now using TWO layers of Landscape Fabric as together, they do a better job of inhibiting the roots from penetrating into the water reservoir.

Be aware that I have not yet finalized the optimum SWC grow media, as I am still trialing different combinations. As a default for now, mix in a 4:1 ratio of Potting Mix and Perlite.

Ray

huntsman · September 3, 2009

Thank you -

email sent...

Salty_Dog · October 13, 2009

Fantastic info Ray,

I too was wondering the benefits vs. downfall of a large water reservoir?
Benefit being longer time left un-manned and perhaps more stable water temp Downfall being the water gets stale and dirty.

I used to think like you, larger the better... but you have brought up an interesting point. I made a miniature Earthtainer out of clear plastic and it sits in my kitchen for seedlings, after seeing how the water goes in the reservoir, I just flush it and refill it with clean fresh water.

Which was going to lead me to a question I was going to post, if anyone flushes the water in their Earthtainers?
IE: just leaves a hose running in the filler tube while watching the overflow holes in an attempt to do a water change?

rnewste · October 13, 2009

Salty,

The automated valve approach gives you an option of maintaining the residual water level as "just enough", perhaps an inch or so, and this keeps the water churning better than a 4 inch deep reservoir. Of course, as you note the trade-off when manually filling the 'Tainers. In this case, certainly "flushing" the 'Tainers when filling with a hose is highly recommended, probably on a monthly basis, at least.

Here is the direct link to the Rev 1.8 Guide.

http://earthtainer.tomatofest.com/pd...tion-Guide.pdf

Ray

Salty_Dog · October 13, 2009

Thank you Ray

Very much appreciated.

August 30, 2009	#1
rnewste Tomatovillian™ Join Date: Apr 2007 Location: Campbell, CA Posts: 4,064	Increasing Water "Churn" in Self-Watering Containers I once thought is was a "good thing" to have a large water reservoir in the design of a Self-Watering container, but I now take the extreme opposite view today. What I have found is that water held in a large reservoir can stagnate, become an easier home for mosquito breeding, and buildup of algae growth on the side-walls that are constantly under water: The availability of the ingenious Automated Watering System from the EarthBox Company now permits "always on" level control so that you can precisely control the water depth to an eighth of an inch accuracy. The passive system is easily adaptable to homemade SWC units. On the left, is the "stock" AWS unit as it comes from the EarthBox folks. It is quite simple to lengthen the sensor tube from the original 10", to what I use in the EarthTainer of 11.5". This keeps the water level in the 'Tainer to about 3.5" at all times. But in an effort to minimize algae growth, etc. and more importantly, to have the reservoir water as "fresh" as possible at all times, I wanted to have kind of F.I.F.O (First-In-First-Out) system where water would be constantly "churning" at the very bottom of the 'Tainer. So what I've now done is to lengthen the sensor tube to 14" thus holding the water level at a constant 1". Since the two tomato plants will consume one to two gallons per day in mid-season, water should cycle through the 'Tainer every 24 hours or so. I realize that as a liquid, I won't get 100% F.I.F.O. but it should provide fresher water to the plants with this approach. Of course, this significantly increases the frequency of watering that one would have to do manually, and the AWS makes this a "don't care" event. The AWS unit cost on a per plant basis works out to be under $5.00 today (They are having a Sale on currently at the EarthBox site). I figure a 10 year service life, so at under 50 cents per year cost per plant, this system is a real bargain for the time savings, and peace of mind when away on vacation. I suppose if one had a 'Tainer on a perfectly level surface, you could experiment with keeping the water level at one-quarter inch at all times using a 14.75" sensor tube - - but I'll stick with the constant one inch water level for now. Ray

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September 3, 2009	#2
huntsman Tomatovillian™ Join Date: Jul 2009 Location: Johannesburg, South Africa - GrowZone 9 Posts: 595	Hey Ray! Really glad I read this, as I will start building my first EarthTainer on the weekend. I have the PDF you produced, but would like to know where I can find all of the amendments you have made over time? Much obliged!

October 13, 2009	#5
Salty_Dog Tomatovillian™ Join Date: Oct 2009 Location: Lorne, Australia Posts: 188	Fantastic info Ray, I too was wondering the benefits vs. downfall of a large water reservoir? Benefit being longer time left un-manned and perhaps more stable water temp Downfall being the water gets stale and dirty. I used to think like you, larger the better... but you have brought up an interesting point. I made a miniature Earthtainer out of clear plastic and it sits in my kitchen for seedlings, after seeing how the water goes in the reservoir, I just flush it and refill it with clean fresh water. Which was going to lead me to a question I was going to post, if anyone flushes the water in their Earthtainers? IE: just leaves a hose running in the filler tube while watching the overflow holes in an attempt to do a water change?