13 January 2016

Easy Balcony Herb Gardening Using Autopots

We decide to grow a little herb garden our balcony, and by jingo it actually worked. Our brown fingers turned a little green with the help of a gravity fed self watering system - Australian invented Autopots.

Our balcony was pretty much an unused space, an alfresco junk storage area, much like yours. As everybody does at least once in their life, we decide to make a little kitchen garden, some tomatoes and a few herbs.

Our west facing balcony sees no shortage of sunlight so it has to be worth a shot. And while it's a small space there's enough room for a weeny garden. There's only two problems. Firstly, we have absolutely no idea what we are doing. This is easily resolved: simply expect everything to die the first time we try. If a single stalk survives our brown thumbs we'll consider it a success and chalk the rest up to experience, then try again next year. It's like US foreign policy, except the bit about learning from mistakes.

The bigger problem is that we travel a lot. We're away often for a week or two, sometimes a month. How to water the plants in boondocks of Sydney when we're in in the boondocks of China? We can't rely on favours. We can't shell out thirty bucks an hour to a plant sitter to save what is effectively three dollars worth of tomatoes. We have no power or water supply on the balcony so the standard home irrigation system is a no go. We looked into Jerry-building a drip-feed system with a water tank, a solar powered pump, and a timer but couldn't find the right combo of bits and pieces.

Google eventually brings us to the Autopot system which turned out to be pretty close to perfect for us. In a nutshell, you get a tank of water, place it higher than your plants, then run tubes down to your pot plants so gravity does all the watering. This means there's no need for pumps, no need for electricity.

And there's no need for timers because the Autopot system uses a nifty little engineering marvel called a Smartvalve that doses out the water to the plants. The Smartvalve lets in around 20cms of water into the bottom of a specially designed pot (a 'Hydrotray') so the plant will drink from it's roots. When the plant has drunk the bottom of the pot dry the Smartvalve fills it up again. This lets the pot dry out a bit and give the roots a breather before it's next watering, mimicking the wet-dry cycle of nature.

For us garden noobs the trickiest part is knowing when and how much to water the plants. Not enough water is obviously bad, but over-watering is equally passe, flooding the roots and starving them of oxygen until the plant chokes. 

The Autopot system takes over the watering and does a dang fine job of it, far better than us brown-thumbed urbanites could ever  manage. In September we hooked the system up and stuck a tomato seedling in. It went nuts.

The tomato plants don't look super impressive in the photos but hey, we've hacked back the growth...

...otherwise our tomatoes would have taken over the entire balcony, like the monster big plant in Dr Who and the Seeds of Doom, which believe was an Autopot experiment gone wrong.


Besides getting the watering right, the Autopot system has a couple more advantages over growing in soil. Fertilising is a cinch. Measure out a dose of hydroponic plant food and drop it in the water tank. Done. The plants now have all the minerals they need. Fertilising regular soil pots isn't too hard, but Autopots are a heck of a lot easier for lazy noob gardeners like us.

One thing to watch out for is the PH level of the water in the tank. Our tap water is about PH 7. Our particular plants want water around PH 6, so the PH of the water needs to be reduced, otherwise the plants won't take up certain nutrients.

After spending much time fooling around with temperamental PH meters and icky PH adjustment solutions, we figured there must be a better way. We noticed that hydroponic nutrient solution (plant dinner) reduces the PH level. If we actually add the plant dinner according to the manufacturers directions, the PH will be conveniently reduced around about where we want it to be, in our case PH 6.  It's a theory in progress, we're not game to throw our PH meter out just yet, but we reckon we'll work out a system in time.

Sometimes plants need less nutrients hence the PH won't go down as much when we put in the nutrient solution, and we haven't quite got our head around how the PH drifts up and down of it's own accord over time. All our reading suggests not to be too anal about PH, it's good to let it drift around a bit, though if it goes way off it will cause problems. Testing PH is a pain in the arse: the old fashioned match-the-colours PH tape and drop solutions are hard to read, and the new digital testers go out of whack and need to be calibrated all the time.

We had our tomatoes growing for months before we bothered checking the PH, you can get away without it but it is better to have a PH meter for piece of mind. Likewise a nutrient meter isn't essential but is very useful, especially when topping up the tank rather than filling it from scratch.


The other reason plants love Autopots is rooting. Because all the nutrients are supplied in the tank there is no need to use soil or potting mix. Instead you can use other mediums which are uber friendly to the plants' root system. We use coco-coir because that's what all the cool kids use these days. Coco coir makes for a really light airy base for plant roots to go nuts in, and it has other beneficial properties that we don't understand but choose to believe (may we join your cult?). The internet consensus is to mix coco-coir with around 30% perlite to make it even more root friendly. We hate perlite with a passion, gardener's dandruff, it's like adding those little foam bean bag balls to your garden. The stuff blows around and gets everywhere, it's a pain to dispose of.  Next year we'll try growing in 100% coco, no perlite will make re-purposing the coco whole lot more possible. While we hate mixing perlite with coco, plant roots love it.

This curry tree has taken well to the Autopots.

The bay tree seems less impressed, though it lives and is getting some new growth.

Our Autopot eureka moment came when we figured we could put more than one plant in a pot, this is how to make it space efficient.  Our favourite pot has a chili plant, sage, tarragon and thyme (there's room around the back for one more too). These herbs always struggled when we had them in soil pots, but took off in the Autopot, particularly the sage. There seems to be plenty of room for all the roots, apparently the Autopots can handle a lot more root action than regular soil pots.

Vertical space is the bigger consideration. We had to pull out a second chili plant and cut back the sage to give the chili room to spread its wings. We did have Italian parsley growing like crazy at the base of a tomato plant, but Shawn pulled it out, he can't really remember why, and Alison hasn't quite forgiven him.

Next year we'll install tomato cages to try and keep them under control, though some jerry-built bamboo got us by this year. Vertical growth has been kept at bay by the wind, a good storm snapped the tops off any stalks not properly supported.

The Autopot tanks hold 35 litres of water, or about 40 litres if you fill them past the Max mark, though Max doesn't seem to mind. You can use any tank that you can drill a hole into. We could get away with two tanks if we didn't travel, one tank if we didn't have tomatoes. Tomatoes in bloom suck water like crazy. Three tomato plants drank almost an entire tank in a week during summer, and that's after we've pruned the heck out of them.

We recently went away for three weeks and the tomatoes just survived. Two tomato plants drank a tank dry and were drooping when we got back, but they perked up within a day. The bigger tomato plant ('Mr Tomato') drank a tank to himself, but luckily had his water replenished by a visitor, lawyers are useful.

The other plants got by fine on a tank, probably could have gone for four or five weeks. To that tank we had hooked up two pots of basil, a small bay, a small curry leaf tree and the pot of herbs and small chili.

The upshot of this is that we could go away for month and easily feed the plants, as long as they are not ravenous drinkers like those tomatoes. They're a bad influence. When we head off to China later in the year it should be OK because in October the tomatoes will still be young.

In fact going on holiday seems to be the best thing we can do for our plants. After three weeks away at Christmas our balcony was like a jungle. The plants revel in that time free of Shawn poking, prodding and killing them with kindness.

The one worry we had while were away were the Smartvalves. While Smartvalves are the genius component of the Autopot system, they are also the Achilles heel. Smartvalves can get stuck on the 'on' position, letting more and more water into the pot until it overflows and empties a whole tank of water onto the floor. It's rare that this happens but it can happen, so if you need to make sure the water has somewhere to go in case of emergency. On the upside the water will drain out fairly slowly, it's not like having a 35 litre tank of water dumped all at once.

We've had one Smartvalve go bung, fortunately not while we were on holiday. It caused a slow but steady drip-drip-drip through a down pipe, which may annoy the neighbours a little but it's not too big of a problem. It's a good idea to have a spare Smartvalve.

To avoid problems with the Smartvalve, the manufacturers advise using mineral based plant food in the tank, some organic fertilizers may have particles that clog the Smartvalve. It's a good idea to clean the valves now and again, though we haven't really bothered.

The pots themselves come in double or single 'Hydrotrays'. We can't quite figure out if we prefer the double or the single. The doubles mean you can have two plants running of one Smartvalve, which means less hassle. If you seriously want to get the most out a plant then a single pot will work best because the Smartvalve will water the plant precisely to it's individual needs. The single pots are quite large and overkill for a lot of plants, our rampaging tomatoes do almost or just as well out of the small double pots. The single pots are great for growing a number of plants in the same pot.

The double pots have a disadvantage in that the Smartvalve gets more dirt and crap around it, making it more likely for the Smartvalve to get a blockage and flood. If you are using a chunkier growing medium such as clay pebbles or perlite\vermiculite this will be less of an issue, we assume.

On the single pot Hydrotray, the Smartvalve sits in a separated enclosure which does a great job of keeping the muck out. Our single tray pot didn't get a speck of dirt around the Smartvalve after months of use and abuse, whereas the double trays get crap around the Smartvalve in minutes.

Having said all that, we haven't had a problem caused by crap around the Smartvalve after months and months of use and neglect. The designers are mostly concerned about greedy plant roots growing out of the bottom of the pot and making whoopy with the Smartvalve. To aid this there are mesh discs to put in the bottom of the pot to stop the roots. The newer black single pots have an additional plastic insert with a mesh filter to further keep roots and crap away from the Smartvalve. The new black single pots also make it much easier to get at the Smartvalve, which is a serious pain with the older model green single pots. Though the green pots are prettier.

The Autopot system is used in commercial applications, folks daisy chain tens, hundreds, even thousands of these things together, and both the single and double Autopots seem popular in large applications.

Well we've ranted on way more than we planned to. These Autopots have been an obsession for several months and it's nice to write about something besides food, and have a bit of a brain dump. Next obsession...

There's not a lot of information on Autopots on the web, there's a little from the authors and a bunch of posts on dope fiend forums. We're thinking about starting an Autopot site and forum, we're that mad on them. By 'we' we mean Shawn.

For more info see:


  1. My suggestion for a website on all this stuff was 'The Autopottamus'

  2. You almost make me want to garden! Almost:)


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