Last year I experimented with a self-watering system for some containers to grow primarily salads and potentially some herbs. They are placed in a way that makes watering a bit cumbersome, and I am typically gone for days at the time during Summer, so that such a setup is very useful to me. It consists of two containers: a top container containing a soil mix and a bottom container filled with water. From the top container, I have a couple of baskets filled with perlite dipping into the water that wick moisture up into the soil mix (I originally used soil for this, which ended up with some nice mold growth :) ).
This worked reasonably well, and I had some good harvests of arugula and some regular green salads. But I found the moisture level of the soil becoming too high, especially towards the end of the season when the Sun and temperature were not as aggressively evaporating the water.
The soil mixture I used then was a general purpose plant mix mixed with perlite. I was planning on adding even more perlite this year as an attempt to lower the average moisture level, or simply go down to the beach to get some coarse sand and mix that in instead.
Any other things I should consider?
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Honestly a simple drip irrigation system is how I would go. You can set them up with a timer on a garden hose. You can controll how much water each pot gets with the number and type of emitter. Its a lot more setup at the start but once it’s installed they tend to work seemlessly.
It’s a balcony setup without a water outlet, so this is unfortunately not possible.
Some drip irrigators draw from a bucket of water. You just need to top up the bucket.
Beware of soil mixes that have “water crystals” mixed in, they are just microplastics that absorb and release water for a while. I used to have soil moisture behave erratically before discovering these were the cause
Oh, I were not aware of these. I’ll have to check my soil mixture to see if they contain any, and at least be on the lookout when getting new bags. Thanks :)
Adjusting the soil mix sounds like a good idea. Could you also have the upper pots dipping more shallowly into the water, reducing their wicking surface?
The way I designed the baskets in the end was to have holes to allow water to seep in only at the very bottom of the baskets. That way I can still make use of the entire reservoir, but reduce the amount of water that is in contact with the wicking material. This was a change from my initial design that had holes along the whole basket. This approach did reduce the overall moisture I believe (I mean, it should right?), but since it was later in the growing season with higher temperatures, I couldn’t judge the effect very accurately.
I have tried to think up some way that would allow me to completely close of the water from the wicking material and reopen after it had dried out, but so far I’ve not had any luck with this.
The most accurate solution would probably be moisture sensors and controlled valves.
I don’t have a water outlet on my balcony, and I wouldn’t want the noise associated with a water pump running. But I have been wanting to add moisture sensors later, and if I could find some other way to regulate water flow in, I could use that to control it.
Elevated tank and gravity feed?
If you setup a small reservoir on a small table or stand in the corner of the balcony you could do a gravity-feed system. Just fill the reservoir every few days when it gets low, and you could still play around with sensors and valves to control the flow.
Hehe, now there are three different suggestions for a gravity-feed system, so I will need to take a closer look at how I could set that up!
Thank you (and to the other suggestors)! :)
