by Michael Smith (Veshengro)
Clay Pot Irrigation, also known as olla irrigation, is used in many regions of the world including Asia and Latin America, and only more recently in the US in places like New Mexico.
Clay pot irrigation is an effective and low cost and minimum effort method of watering plants, whether in containers of in beds, and the technique is simple as well.
In principle all you do is to take an unglazed clay vessel and bury it in the ground up to the rim. Pour water into the pot and let osmosis do its thing. OK, maybe it is not that simple, but that is how it, basically, works.
There are a few factors to take into account such as the porosity of the clay pot or olla and the surrounding soil as well. The porosity of the vessel depends on the type of clay used, but unless you specifically purchase an olla or make your own clay pots, this factor might be out of your hands. In other words, it may probably not be advisable to use any old unglazed clay pot. In addition, the soil should ideally be well drained. Add compost or organic matter, or sand if needed. Ensure that it is enough to allow water to percolate from the clay pot to the soil and then to the plant root zones.
If you are planning on irrigating a vegetable garden, place each clay pot or olla about 3 feet apart and plant your crops around each olla. Fill the olla with water every week or so, depending on rainfall.
With the Plant Minder from Feed N Leave Ltd. in the UK, on the other hand, you don't have to worry as to whether you top up the container often enough. Checking whether there is still water in the green (blue in the diagram) “bubble” will do the trick.
Plant Minder is the modern way of clay pot irrigation and the principle is the same but it takes it a little bit further in that you fill a green plastic “bubble” - for lack of a better word - with water, turn it upside down into the clay “pot” rather than just fill up the pot with water. This prevents evaporation and also any debris falling into the pot and the water in it. Works brilliant.
A variety of different porosities are available, including for those kind of plants that are rather thirsty, such as tomatoes.
Plant Minder are entirely UK made with the clay pots made in the old pottery areas of Staffordshire.
I have a review sample of the Plant Minder installed in a pot with a newly planted lemon balm plant and I have got it in the pot for the last month or so and, while the plant is growing extremely well, the water i still half full in the green “bubble” which means that very little water, has so far been used from the clay pot. This may also be due to the fact that we have a rather wet summer this year – yet again, much like last year – but the pot does not really get that much rain water.
All I can say is that this system is a real great idea and invention and I can but recommend it to anyone, especially those of us who garden in containers, whether fruit and vegetables or just flowers.
Depending on condition and such it is reckoned that Plant Minder only will need refilling once every six weeks. That does not mean that you do not have to check on it as to whether it may need filling. As long, however, there is water showing in the green plastic globe then you still have more that enough water in the clay pot to water the plant or plants.
Plant Minder is available from PlantMinder.com in the UK and from a variety of garden centers and other such outlets.
© M Smith (Veshengro), August 2008