Question of Self Watering Container

saoodhashimFebruary 15, 2014

Going further with my gardening endeavors, I did some research on you tube and google regarding self water containers.

The model that I like to start with is a reservoir at the bottom of the plant container (close to the rain gutter style - youtube link below). The soil in the plant container will sit a few inches above that reservoir and will be connected thru a net filled with tightly packed soil which will wick the water from the reservoir and pass it on the the soil above. I believe you would have understood what I am talking about.

Apparently the model looks great but it however reminded me of one of the warnings generally mentioned to beginner container gardeners (and I too being one) and that is to not keep the container in the bottom saucer if it is full of drain water because it will result in over watering of the soil inside the container.

Now if this is a real issue with the saucer as the soil from the hole will wick the water inside and flood the roots, what really troubles me is why would the same not be an issue when the net pot will wick the water from the reservoir.

Practically its the same thing but while it is a threat on one side it is a blessing on the other.

Can someone help me understand this.


Here is a link that might be useful: Rain Gutter Watering System

This post was edited by saood on Sat, Feb 15, 14 at 6:33

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Natures_Nature(5 OH)

I was never that big into self watering containers. It doesn't really bring more benefit, just different benefits than other types of growing. In this case, convenience. But, as you stated, if the wick isn't just right, or if your container sits in water, you could be doomed. I don't see how the self watering systems soil isn't constantly wicking water everytime the soil drys, wouldnt the soil wick more water from the reservoir, leading to constant wet roots and all kinds of problems? Maybe a flow pump takes care of that, i don't know..

I noticed on another thread, you were talking about planting in straight perlite and watering several times daily. It's important to note, you cannot use just perlite in a self watering container. Their has to enough cappilary pull in the medium for it to wick moisture from the resovior. You would need a good medium to wick that moisture up, or the plants are going to be dry as a bone.

I watched that video you linked. Man, that guy is hooked on the rain gutter system, huh? I can see what brought you in.. But if the fertilizer/water is constantly recycled, wouldn't you have to closely monitor pH, etc? I think it's a lot more than just plant and harvest like the guy in the video makes out. What happens when your nutrients start bonding together and your plants are showing signs of it, would you have to take apart the whole system and clean it down thoroughly? Boy thats a lot of work for just maintenance. The guy in the video said something along the lines of " I just plant in june, watch em grow in july, and harvest". What happens when it gets really hot in summer and heats up the fertilizer solution, we all know that some fertilizers are heat sensitive(the hotter, the less fert). So say you set up your system in june and measured the fert etc, then in july it gets really hot and the fertilizers burns the plants.. Do you constantly have to keep adding fresh fert/water? It seems like a lot more work than plant and harvest.. If something goes wrong, it could be a disaster..

    Bookmark   February 15, 2014 at 10:47AM
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While I did not want intend to discuss the pros and cons of the system, but this guy seems to deny conventional wisdom.

Have a look at this video. What he is promoting is to keep the grow bags / containers constantly in an inch of water and get phenomenal growth. Whereas the container gurus all over the internet say never to do that else you kill the plants by over watering?

Now this is two opposite extremes....Any comments?????

Here is a link that might be useful: Keep the containers in water

    Bookmark   February 15, 2014 at 12:34PM
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Natures_Nature(5 OH)

There is no one size fits all, every plant has different needs and grow in different environments. If the plant is native to swampy conditions, provide swampy conditions. If the plant grows in sand, grow it in sand. Find out where that plant you want to grow grew natively, and try and mimic that habitat.

    Bookmark   February 15, 2014 at 2:21PM
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rnewste(8b NorCal)

As a reference point, you may want to read the EarthTainer Construction Guide below. I am not selling anything - the design I have posted is free of charge. It is being used in locations where water conservation is an important factor. In Saudi you would need to improvise with locally available materials.


Here is a link that might be useful: Final EarthTainer Guide

    Bookmark   February 15, 2014 at 3:33PM
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I had good success last season with Grow Boxes. In fact, my tomatoes in the Grow Boxes were bigger and better producers that my tomatoes in my raised beds, with the exception of one plant in a raised bed that did great. It was a Juliet, by the way. This year I am trying the rain gutter method, chiefly because I know I will be out of town for a week or two this summer and I want to automate the watering.

I am sold so far on the sub-irrigated method. Attached is a photo of a summer squash (one plant) in one of my Grow Boxes, and in the background you can see the tomatoes in another one.

    Bookmark   February 22, 2014 at 10:28PM
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Ohiofem(6a Ohio)

Saood: I watched the video, but I didn't actually see any of the tomatoes he said his neighbor grew. He shows his ignorance in several ways that make me question his claims. For example, Minnesota midgets are melons, not tomatoes. There is a Mexican midget cherry tomato, which is likely what he is referring to. He doesn't know that all bees that collect pollen are female worker bees. He uses a tiny tomato cage that would be useless for a full size tomato, which the Mexican midget is, in spite of its name. He says nothing about how standing water open to the air like that will become a foul swamp full of mosquito larva.

In a proper SWC, you don't actually have perched water inside the container. The wicking basket "fools" the water into thinking the bottom of the container is several inches below the actual bottom. So the soil stays moist from the capillary action moving water up into the pot, but not soaked like it would if you set the container directly in the water.

    Bookmark   February 23, 2014 at 1:12PM
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In the first place, I would think you would need a pretty tight potting mix to get good capillary action with this system. That rules out a well aerated mix like the 5-1-1. Second, without periodic flushing, salts would likely build up in the mix and inhibit plant growth. I saw the video and applaud the guy for thinking outside the box, but he seems to have designed this system for his convenience, and not for the plants.

    Bookmark   February 23, 2014 at 6:13PM
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seysonn(8a WA/HZ 1)

If by "Self Watering" it is meant "Bottm Watering" then it can have serious problems for a lot of plants that do not like WET FEET all the time. Just consider the purpose of 5-1-1 and Gritty mix. The whole concept is "DRAINAGE" with just right amount of moisture retention. Constant bottom watering will create a soggy soil due to the principle of PERCHED WATER TABLE. Now if you have a peat based medium, it will stay wet all the time. It might be fine for swamp plants like fern, bu as far as I know most garden veggies won't tolerate that.

    Bookmark   February 24, 2014 at 2:06AM
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But most self watering systems are practically bottom watering systems. While everyone (including the experts) goes to every length in praise of self watering systems, they equally warn of the huge dangers of bottom watering. It sounds very mysterious to me.

How do you see that?

    Bookmark   February 24, 2014 at 2:17AM
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Btw, I tried to resolve this mystery in one of my other posts on "Container Soils - Water Movement and Retention" and seeking comments from the experienced ones.

Moving on I am thinking of trying out Self watering containers. I was just wondering as to why it works and why the water is not being wicked up infinitely and result in root rot. The reason that I came up with and I would need the the experts confirmation / comments over here is this

1/ A self watering container is constantly sitting above water and after all the soil in the container has just enough moisture, the water keeps on wicked up until PWT levels are reached (an a portion of it may well be inside the pot itself). Now since the soil at the bottom is constantly in water, the roots do not grow into that PWT area and remain above that level for entire life cycle of the annuals (veggies) and they keep on getting the moisture and the air at the precise time that they need.

2/ On the other hand if we were to keep a container already having roots reaching the very bottom of it (the container) in a saucer full of water, because of the PWT the water will get wicked in through the drainage holes and getting the plant over watered since the roots in the PWT area will rot.

3/ Now that would mean that to make a very easy self watering container would be to let the container sit in the water saucer (perhaps an inch deep) and the potting soil will wick water up and also maintain that PWT. In order for roots to not reach the PWT area, we must ensure that the saucer is always full of water. (Ofcourse the container should be deep enough to allow for both PWT space and the enough free soil space for the roots)

Am I reasoning it correctly?


I did get a reply but I am still trying to understand it :) You know a newbie can have trouble understanding everything the experts say....

    Bookmark   February 24, 2014 at 2:30AM
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Ohiofem(6a Ohio)

There are many successful self watering systems that work very well, and one of the most impressive in my opinion is the Earthtainer developed by Raybo, who linked to his guide above. All the ones I know about depend on having a wicking basket under the main container that draws just the right amount of moisture up into the container. The container with potting mix doesn't sit in the water. They also depend on a container mix that is very absorbent, usually with a large fraction of peat. The container is covered and never watered from above so the peat-based mix doesn't get compressed. As I said above, there is no perched water inside the container.

    Bookmark   February 24, 2014 at 9:47AM
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seysonn(8a WA/HZ 1)

I would think that bottom watering/self Watering can be used, PROVIDED you know EXACTLY how much and how often you have to do it. This way the plant gets just the right amount of moisture.

I think constant bottom watering/self Watering, can/may accumulate some salts/minerals over time. That is why flush watering is better. FW also gets rid of stagnation, that can be home for diseases and infection.

Anyway, SW/BW runs against the idea behind 5-1-1 mix. The whole thing revolves around, drainage, moisture control and aeration.

    Bookmark   February 25, 2014 at 6:21AM
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