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Just about everything in Quito comes with its own special challenges. The altitude and climate provide plenty of scope for things to go pear-shaped, and mean that, from boiling an egg though to baking and gardening, nothing can be taken for granted.
In Quito, there can be downpours for days, followed by weeks with no rain at all. The sun is powerful and evaporation is faster due to the lower pressure. This all makes gardening a challenge, especially for pots and planters, which can dry in a matter of hours.
But all is not lost. Step up SIPs! SIPs = Sub Irrigated Planters.
What is a SIP?
Wikipedia’s page is pretty poor, but there are plenty of resources to be found around the web and a community of avid enthusiasts. And this enthusiasm is not surprising, because SIPs are amazing! I’ve enjoyed the process and the results so much I’ve become an evangelist (hence this entry).
A SIP is any method of watering plants where the water is introduced from the bottom, allowing the water to soak upwards to the plant through capillary action (Wikipedia).
So, why SIP?
- SIP because you don’t want to water everyday.
- SIP because you don’t want to waste water.
- SIP because you don’t want to kill your plants through under or over watering.
- SIP because you’re lazy.
- SIP because you just want to.
The basic principles of SIPs:
Essentially a SIP aims to emulate to some extent the way plants work naturally. Plants generally suck up water from below, taking what they need. Traditional pots and planters turn this upside down, with the water introduced from the top. This is rather foolish, maximising evaporation and risking both over and under-watering. One consequence of this is that we’re sensibly advised to water in the evening to reduce evaporation. With a SIP, you can water effectively anytime.
There are lots of different designs for SIPS, but the best take into account the following priciples:
- Water is fed in through a tube which feeds a reservoir in the base of the planter.
- This tube also allows air to enter into the reservoir, this enters the soil via small holes.
- An overflow is provided just below the top of the reservoir, this prevents overwatering and maintains an airspace.
- A wicking material (cloth, newspaper or just soil) allows the water to reach the plant via capillary action.
- Where appropriate, a mulch or newspaper should cover the soil to further prevent evaporation.
How to buy/make a SIP?
Although you can, there is no need to buy a SIP. I highly recommend making your own, using the above principles, and drawing on the wealth of designs on the web. And if possible try to reuse and recycle to do so.
Let’s start simple and move on… Perhaps the most basic SIP is the single soda bottle SIP. Here’s my schematic:
And here’s the real world version (click on the image for a larger copy).
This design does, in the name of simplicity, violate my first principal of a good SIP, in that it has no tube to feed the reservoir
Here the SIP is growing oregano. Generally the occasional rain is enough to water it, the water passes through the soil and fills the reservoir; however sometimes I do need to add extra water – a tube would make this more efficient but would also complicate the simple, easy design.
I’ve also used this design for growing coriander from seed, this worked very well, reducing the chances of the soil drying out and the seedlings dying.
Ok, so what about more sophisticated designs?
SIPs are pretty much only limited by your imagination, and provide a lovely opportunity to get creative. Following a few other attempts I I settled on this design for long planters. Here I’ve used a variety of old bottles and some old tubing. The three white bottles are all joined together and fill directly from the tube. I drilled small holes (with a Dremel, but they could be punched or cut) in the tops and sides. The top holes allow air to the soil, the side holes release water into the surrounding soil (added later!). The transparent bottles are not connected to the white bottles but fill up as water exits the white bottles.
Overflow. If you look closely, you’ll see that the vinegar bottle sticks though the side of the planter, thus acting as the overflow. Excess water from the soil enters into the three transparent bottles, and when it reaches the level of the exit hole (vinegar bottle top) it pours out of the planter, preventing overwatering. The nice thing about this design is that if for any reason you want to really soak the planter (perhaps you’re going away for a while), all you have to do is put the lid back on the vinegar bottle (remembering to remove it when the soil has soaked).
Fill Pipe. The fill pipe is topped by the top section of a plastic bottle. I generally join these to the pipe by cutting a hole in the lid, and then sealing the connection with a glue gun.
For the finished product, see the top of the article!
What else?
For me this is pretty much the beginning, there are plenty of ways of improving these systems, including developing a way to make a truly self watering SIP (again, there are plenty of ideas around on the web). The bigger project is to make a large self watering planter using rain water. I’ll update when I’ve made some progress! In the meantime, try for yourself, and let me know how you get on.