Drip irrigation using the Claber Oasis. I set this up to supply water to a few of my containers while I was away on vacation.
All the best vacation time is during the growing season. That's the problem with gardening. And for some time now I've been trying to find ways to keep my balcony plants watered when I'm not around. Nothing beats having a human being around that can follow instructions and make some judgement calls for you. You never know what the weather will be like while you are away. Overcast and rainy means your plants will not be needing as much water. But hot and sunny could mean the end of a crop that craves moisture.
I've made attempts at drip irrigation and have never been happy with the results. But recently I needed to be away from the balcony for a few weeks and didn't have access to anyone I could count on to keep the plants watered. I didn't feel like burdening friends and family with having to drop by every other day and haul water out to the balcony. Drip irrigation can work using a low pressure gravity fed water source but you need something to turn it on and off. All of the garden water timers available that I have researched require a water source with considerably more water pressure than I can provide.
Then I came across the Claber Oasis. It's nothing more than a 6.5 gallon tub with a battery power timer and solenoid valve. To be honest, it's rather cheaply built. It comes with a set of fixed rate drippers and a good length of water supply line. The timers can be set to open the value for a preset number of minutes every 12 hours and the drippers will deliver water at a fixed rate. The timer has settings marked in days: 10, 20, 30 and 40. Which means, using all 20 of the supplied drippers, the Claber will drain all of its water in the number of days set on the timer. The settings translate into 4, 2, 1.5 and 1 oz of water per dripper per day. I paid more for the Oasis than I really wanted to. Construction could have been a bit more solid. It really isn't much more than a timer, valve and tub. It runs on a 9v battery. The Claber Oasis is made for indoor plants but my balcony is practically indoors to me anyhow.
The timer panel on the Claber Oasis. The timer is power by a single 9v battery.
Drippers are setup in a loop and the supply line starts and ends at the Oasis. Water will flow into both ends of your supply line. This helps to balance the pressure of the water fed to the drippers. To use the Oasis properly it needs to be placed a couple of feet higher than the highest dripper on the loop. I takes a bit of playing around to get it just right. At first you need to run it with the loop open somewhere and leave it that way until water is flowing through both supply lines. You cannot have any air trapped in the lines. But once the loop is flowing smoothly and reconnected, you wont have any problems as long as you keep the tub full of water.
To setup my temporary watering system, I moved all my containers to the back of the balcony, out of the sun and clustered around the Oasis. I had one container that was up high and I could not place the Oasis any higher than this container. So I tried to setup drippers higher, almost at the same level as the output ports on the Oasis. Water didn't flow out of them at first. So I opened up the drippers and cut a small channel into the part of the dripper that limits the water flow. This allowed water to flow faster through those drippers. I also made sure I marked the drippers so in the future I would know which I had modified. With faster flow drippers up high, I was able to get water flowing to all dripper on the loop.
Twenty of these drippers are supplied with the Claber Oasis.
First time using the Oasis it did a good job. Second time I didn't bother with the higher up plants and it did wonderfully. I even left it hooked up for most of the summer and just kept filling the reservoir. My peppers and basil loved it. For some plants you will need several drippers. I had 8 drippers in my tomato container and this was not enough. But 4 drippers in my pepper container was just fine. To prevent moisture loss I covered the tops of the containers with plastic. Because the plants were receiving water from the drippers I didn't need access to the soil surface to water the containers myself. I also like to do this with my self watering containers.
Where the Oasis failed me was in its second season on the balcony. Initially I had some problems with the valve sticking. Once water started to flow out of the ports on the bottom of the tub, I noticed flecks of rust in the water. But after a few open/shut cycles it stopped sticking and seemed to be working fine. I got everything setup and let the system run for a few days and then noticed it was no longer functioning. The timer had died. A new battery didn't fix things. I played with it a bit and could convince it to function for a few seconds but eventually the activity light would stop flashing and the valve wouldn't open or close, no matter what I did.
Another device that can help keep your plants watered is this ceramic watering spike. These are short hollow porous ceramic spikes that have a plastic cap on top with a rubber hose attached. You fill the spike with water (to prime it), stick it into the soil, and put the end of the water hose in a container of water. The container should be lower than the spike so the water is drawn up and into the spike. If the water supply is above the spike, water will be siphoned down into the spike, forcing water into the soil. You run out of water faster and make the soil really wet.
The porous nature of this ceramic device allows water to seep through its walls.
I've used these spikes with indoor plants and they work great. Out on the balcony I stuck several into a large container that had peppers and celery growing in it. The ends of the hoses I attached to a weight and let them sit in a large bucket of water. The spikes had to pull water up from this bucket. It's a really slow way to get water into the soil. And even with the container covered in plastic to reduce evaporation from the soil surface, the spikes were not able to deliver enough water in my opinion. It was enough to keep the plants alive but I would have liked more water. These spikes are great for small containers that aren't exposed to too much sunlight. And they are especially good for indoor plants. If you can, move your plants out of the sunlight to keep the soil from drying out too fast.
For my self watering containers, what I would really like is something that can flow lots of water into the reservoir every day until it is full, and then cut off the water. But for my non-self-watering container plants, the Oasis was great. I still don't have a good solution for keeping the plants stuck in higher up containers well watering. For those I would like something to pump the water up to them: a pressurized water source feeding drippers or sprinklers. Something that can run unattended for a couple of weeks but can also be monitored and overridden remotely, over the internet. A few web cameras would be nice too. A project for next year perhaps.
But even with all of these devices, nothing beats having someone around who can decide what needs to be watered, when and how much.