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. ----Quote---- 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? ----Unquote--- 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....

As I was thinking more about this, I will plan to flush the tanks monthly. Before I refill them, I can let it sit empty for a couple hours to get some more air to the bottom of the wick. Hopefully that should keep the mix happy for a few years. If you are using potting mix for the wick you do not need to worry about it's condition at all. The only purpose it serves is to wick the water upward and everything else being equal the more broken down it is the faster it will occur. Common advice when filling a container is to not tamp the mix down, but just water it in. This is to reduce compaction. This advice is reversed when it comes to filling the wicking chamber with potting mix. In this case you want to mash it down firmly so the particles make good contact with each other. Best to prewet the mix as well so it mashes down even better. This distance the water has to travel before it makes it to the growing area of the mix is considerable with your design. I would recomend testing the design this winter and see if water wicks efficiently, particularly when the reservoir is near empty. If not you can try using a different mix in the wicking chamber. Peat works exceptionally well in the wicking chamber. Basically the qualities you want in the wicking chamber are the opposite of what you want in the growing area. Your wick has to overcome gravity and if you need the water to travel upward 12" before contacting the growing media you want a water sponge. The climate here probably won't cause me to use too much water. I am about a mile from the coast and barely saw summer temps break 85. Oh, you will be fine then. Most of the folks reporting having to refill the EBs 2x/day with tomatos are dealing with hotter and drier conditions. For me it was never more than 1x/day with a 4 gallon reservoir and that was with 6'tall plants, unpruned and bearing fruit.

My reservoir is actually 35-gallon barrels on their sides and plumbed together at the bungs. I cut holes in the sides (now the top) of the barrels and inserted the drain pipe. When I filled in the bed, the soil went down into the drain pipes to act as wicks. The reservoir fills from one end and overflows into the next bed, which I built about 4 inches lower than the first bed. As previously mentioned, these beds are plumbed into the overflow on my rain barrels. I initially filled them from the hose but I have never needed to add more water in the last 4 years. That includes the awful drought we had here in Kansas in 2012. Plants in these beds typically do better than my other beds. I think it is because they have all the water they want but their roots are not continually sitting in water. Plus the rainwater doesn't have chlorine, which I think makes a difference. While this system works great, if I were to build another bed I think I would dig the hole, line it with a pond liner, install short drain pipes vertically for the wicks, fill it with gravel (the bigger gravel size the better to increase the water volume), and use a landscape cloth, with holes for the wicks, to keep the soil out. It is just a simpler design plus I have had a trouble with tree roots invading these beds. A pond liner might keep them at bay.

Couple of quick things...don't make the bed right up against the fence - with a bed 3ft wide you will need room on the fence side to reach into the bed. Leave about 3ft between the bed and fence (4ft if you can), enuff room for your legs from the knee to an extended foot (and more) so you can kneel down. The peat has no nutrients so you can leave that out of the mix. I don't think Home Depot does this anymore but I made lots of beds when they sold 'cull wood'. It was bent, warped, chipped, or had some other defect but was fine for the garden. They always cut it to 4ft lengths and the price varied from $.51, $1.01, $2.01, etc. I got most for $.51 or $1.01 Some were treated some not - some 2x some 1 or 3/4". The 2x will last longer. I have some untreated 2x beds 10y/o. I just placed the 4x4 frame on the ground, no corner post needed - they haven't gone anywhere yet either. IMO the SqFt method is the way-to-go.