How much water

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David Bracey

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How much water
« on: December 03, 2012, 10:51:01 AM »
This article was copied from the South Australian MGS newsletter. It makes a lot of sense

""Help! How much do I water?
Just had the irrigation system flushed and a couple of leaks fixed and the irrigation guy said I should water the lawn three times a week for 10 minutes at a time and the garden, on drippers, three times a week for 30-45 minutes at a time.

He‘s wrong‘ I thought but decided to do some research before resetting. Lo and behold there is a bewildering array of advice! I‘d always worked on about 30 mins every 10 days to 2 weeks for the lawn and 2 hours about every fortnight for the garden, BUT the SA Water website says it depends on the type of soil, among other things. They argue that if you have sandy soil, long soaks do nothing because the water drains straight through the sand well below the reach of the roots. Good point I thought. They recommend that sandy soil needs more frequent watering, with small amounts of water. Improved soils
and sandy loam hold more water so need less frequent and deeper watering, and so on.

To test your soil, they recommend watering until the water pools, usually no more than 5 minutes, then turn water off, leave for half an to an hour to allow it to soak in and then repeat the cycle. In between cycles, dig into the soil to see how far it has gone down. Repeat until water has reached the root zone.

Another website recommended the standard I‘d been using, while a third, from a lawn company, recommended watering for as long as it takes to fill a shallow container to a depth of 2.5cm.

As our lawns and garden beds are largely sandy loam, but veering to sandy and water repellant, I‘m going to try the pulsing method of short bursts. Should be interesting. My irrigation guy may have been right after all …
Happy watering!""
MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

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ritamax

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Re: How much water
« Reply #1 on: December 03, 2012, 11:38:37 AM »
I have been constantly experimenting with the sprinkler irrigation for the last 1,5 years. Deep soaking on my clay soil with sandstone underneath causes water logging. In spite of all the advice about infrequent deep soaking, short, frequent watering has proved best for my plants as long as they are not established (when that time will come I will certainly experiment with more infrequent watering). I do deeper soaking from a hose for trees some twice a month in the summer as the sprinklers do not really cover the tree roots. But I wonder how deep can the roots grow if you get large blocks of sandstone if you go deeper, so the idea about plants rooting as deep as possible is not realistic in all kinds of soils. It was interesting to see when I mended one leak in irrigation pipes and excavated a place around grevilleas and metrosideros, that the plants had grown very long roots towards the leakage, so the plants will find their water wherever it comes from, no need to drown them. With geotextile and lightcoloured gravel the soil keeps amazingly cool and moist underneath (compared to the other areas), so the watering has to be very considerate. There is information from Jeff Gillman, that the soil would get heated and leaves scorched with gravel, but none of this has proved true in my garden. The rainworms live underneath, so there must be aeration, too. Good picture here about the ideal soil structure (for ornamentals, vegetable would need more organic matter I suppose): 25% air, 25% water, 40-45% mineral, 5-10% organic matter. 
Here is Linda Chalker-Schott's article about drought-tolerant plants and water.
http://www.puyallup.wsu.edu/~linda%20chalker-scott/Horticultural%20Myths_files/Myths/Xeriscaping.pdf
Hobbygardener (MGS member) with a rooftop garden in Basel and a garden on heavy clay with sand 600m from seaside in Costa Blanca South (precipitation 300mm), learning to garden waterwise

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Fleur Pavlidis

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Re: How much water
« Reply #2 on: December 03, 2012, 12:06:39 PM »
It only makes sense if you don't believe in water-wise mediterranean gardening. Leaving aside the lawn, what drought resistant plants need drip irrigation three times a week if they've been raised to be tough no matter what the soil?
MGS member, Greece. I garden in Attica, Greece and Mt Goulinas (450m) Central Greece

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ritamax

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Re: How much water
« Reply #3 on: December 03, 2012, 01:47:57 PM »
Well, it is not a matter of believing, but observing what works and putting up a garden with no excessive losses, the root systems have to be established first. During the drought the small roots dry up and the soil gets compacted, so the plant will not have a chance to establish itself. To water a little, but more often does not conclude automatically that one consumes more water, it is also an attempt to be water wise. With 6 months of drought every year, I don't see any option for the irrigation system. I would have only succulents then, as many of my neighbours do.
Hobbygardener (MGS member) with a rooftop garden in Basel and a garden on heavy clay with sand 600m from seaside in Costa Blanca South (precipitation 300mm), learning to garden waterwise

David Bracey

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Re: How much water
« Reply #4 on: December 03, 2012, 05:30:44 PM »
The recent posts "How much water", "Hydrating Gels" and "Biomass" are really getting into the nitty gritty of gardening in a mediterranean climate.  As much as I think Dr Chalker-Scott talks a lot of sense, the information is, I think, largely relevant to her climate ie maritime temperate. I really think you have to garden in a med climate to experience its limitations. There is a huge lack of knowledge.

As Fleur correctly says "what drought resistant plants need drip irrigation" (if they have been raised to be tough----------not sure how you raise tough plants, though).

It comes back to "what is good practice" in a mediterranean garden and there I think the jury is still out. Is it donkey manure as recomended by Daisy, mulching, irrigation, plant selection, expectation, Northern perception or what?

Plants are not cheap and the last thing that gardeners want is to loose them, for what ever reason. 

My wife gardened with me in the Gard for more than 15 years and could never come to terms with brown plants in the summer and winter, different planting seasons, no watering and so on.

What are other Forum members ideas ?





MGS member.

 I have gardened in sub-tropical Florida, maritime UK, continental Europe and the Mediterranean basin, France. Of the 4 I have found that the most difficult climate for gardening is the latter.

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ritamax

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Re: How much water
« Reply #5 on: December 03, 2012, 06:41:15 PM »
Two things: of course it is ideal to grow one's own plants from seed in the soil available, but all of us absentee gardeners are hardly able to do that. We have to take, what the nurseries and garden centers offer and that is often quickly in peat and fertilized grown stuff, which then hopefully adapt to the given soil.
Why is that so important not to water plants in summer and let them turn brown, beats me. Me, us and my tenants enjoy green plants in the summer, nothing dies back except that ceanothus, which is one of the few plants, that really dies of summer watering. I would not wish to buy new plants all the time. A garden is not same as the wild nature, is quite clear. 
Not only Linda Chalker-Scott, but many other garden authors as well, write about water stress and that plants' small roots die of lack of water. How is Mediterranean so different from the other climate zones? I do water my plants in Basel as well.
Hobbygardener (MGS member) with a rooftop garden in Basel and a garden on heavy clay with sand 600m from seaside in Costa Blanca South (precipitation 300mm), learning to garden waterwise

Umbrian

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Re: How much water
« Reply #6 on: December 04, 2012, 08:50:37 AM »
This topic is getting a lot of attention and deservedly so. The problem of IF to water, WHEN to water, HOW to water etc occupies all of us at some time or another and the problem is very different for those of us who live and garden permanently in  Mediterranean climate areas and those who "come and go". I am fortunate to fall into the first category and that certainly makes things slightly easier.
From the outset, when we moved to Italy nearly 15 years ago I was determined to develop a waterwise garden, and am still adhering to that principle. As the years have gone by our annual rainfall has lessened and its arrival become more erratic. A spring ,that used to serve our household needs ,has been dry for 2years now and so to have a garden that does not need watering to survive is essential.
As a beginner I decided that soil preparation and wise choice of plants were the two most important things. I was eager to grow things that I had not been able to have before but realised that I should proceed carefully to avoid not only disappointments but useless expenditure. With this in mind I decided to do the "structural" planting with fairly "fail-safe" subjects and to create interest and variety with more "difficult" things.
I also developed the garden quite slowly, creating one area at a time so that I could give it the attention it needed - good soil preparation (as mentioned before), careful choice of plants taking into account the prevailing conditions in that area, ie full sun all day/part of the day, exposure to winds etc. Despite my eagerness to begin to see the fruits of my not inconsiderable labours, weed infested land compacted in many places by house restoration work and many years of neglect, I decided the way to go was to plant small and really pamper everything for at least the first year, watering daily during that first year once the really hot weather arrived.
Certain subjects were watered more sparingly during their second summer but in the main I was successful with establishing things well enough in their first year, not only to survive but to grow into strong specimins. Of course there have been failures and disappointments and occasionally things have to be helped through difficult times but with careful thought and constant observation it is possible to garden in Mediterranean areas without the worry of watering. Each year brings greater knowledge of what will succeed, ( and where) and what not, and this experience is both exciting and invaluable.
MGS member living and gardening in Umbria, Italy for past 19 years. Recently moved from my original house and now planning and planting a new small garden.

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John J

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Re: How much water
« Reply #7 on: December 04, 2012, 05:03:21 PM »
Here in Cyprus the question of whether or not to irrigate gardens in the summer depends less on the plants involved and the soil conditions and more on the availability of water. Being an island we are almost totally reliant on what falls out of the sky in winter as rain or snow. Some desalination is carried out but this, currently, is negligable. If the winter precipitation fails to replenish the reservoirs then summer rationing inevitably follows. If the rains fail for consecutive years (5,6 or 7 dry winters on the trot are not uncommon) then the situation can become desperate. Water for domestic use (drinking, washing,etc) becomes an absolute priority followed by agricultural irrigation with the watering of private gardens a selfish, anti-social luxury. The last drought period involved the majority of the consumers being subjected to rationing of domestic water supplies to 24 hrs on/24 hrs off, with some areas, the capitol Nicosia included, having 24 hrs on/48 hrs off. Unfortunately this still did not deter certain individuals who insisted that they would continue to water their gardens regardless as long as they could afford to pay the cost per unit consumed. They seemed unable to grasp the reality that once the water was exhausted and the dams were empty no amount of money could buy more. During this period the situation became so desperate that tankers were employed, at great expense, to ship water from Greece, literally a drop in the ocean. In the occupied north of the island they experimented with towing water-filled 'balloons' from the Turkish mainland. It failed as they proved to be porous and the water was saline by the time it arrived. With the experts predicting lower levels of precipitation and higher temperatures for the island as this century progresses it is not only advisable but imperative that ways are found, by whatever means, to reduce the amount of water used to irrigate private gardens.
Cyprus Branch Head. Gardens in a field 40 m above sea level with reasonably fertile clay soil.
"Aphrodite emerged from the sea and came ashore and at her feet all manner of plants sprang forth" John Deacon (13thC AD)

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JTh

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Re: How much water
« Reply #8 on: December 04, 2012, 05:18:17 PM »
Ritamax, the basic difference between watering plants in the Mediterranean and in Basel (as well as in Oslo) is that water is scarce in the first region, and should not be wasted. As John J just wrote: ‘it is not only advisable but imperative that ways are found, by whatever means, to reduce the amount of water used to irrigate private gardens’.

During the first few years at our house in Greece we had plenty of good quality public water, but slowly new houses were built along the beach, all of them with big gardens, lawns and thirsty plants, and the water supply rapidly diminished, a major reason was that those having houses below us were using a lot of water on irrigation. Around ten years ago there was hardly any water in our taps in the summer, not even at night, and the water was no longer potable. Our house is about 40 m higher up, and we were told that we could not expect the water pressure to be high enough to reach such extreme altitude! (We are 200 m from the beach.) We were finally saved by our neighbour, who had to drill for water since he has a small hotel; he lets us use water from his well, but we can’t waste it.  Since we are not there most of the time, we had to choose plants that would survive with minimal watering, but slowly we have managed to create a green zone around the house. We have also tried to protect the wild bushes along the fence as much as possible, and I see from the photo on Google maps that we have succeeded. But the main thing is that my own attitude has changed, slowly I have begun to look at the natural changes in the landscape in a different way, dry and brown is not necessarily ugly, as long as it is part of the plants’ natural cycle..

We have some friends nearby who look after our house when we are not there, and they also water some of the plants, but they are getting older and they suggested I should install some automatic watering system which would reduce the need for lugging a watering can around the place. So I did this summer, and it works quite well, but accidentally I found out how much water is consumed each time I put it on, (the neighbour’s water pipe was broken, so we used water from a water tank we use as an emergency reservoir, and it was easy to measure). I was shocked to see that 300 l of water was used in one hour, although the drips had been regulated to a minimum. This information was useful, next year I will reduce the watering time considerably.
Retired veterinary surgeon by training with a PhD in parasitology,  but worked as a virologist since 1992.
Member of the MGS  since 2004. Gardening in Oslo and to a limited extent in Halkidiki, Greece.

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ritamax

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Re: How much water
« Reply #9 on: December 10, 2012, 01:37:16 PM »
Thank you all for the informative output. We are lucky on Costa Blanca, there are no restrictions on water. The water comes from inland, where they have enough rains. The new desalination plant which functions on solar energy will open soon (it already received some prize for the innovative technique). So, yes, the water should not be wasted, but there is nobody to control it. I have planted trees and shrubs to create shade and a cooler microclimate in the garden, so that less watering will be needed in the future. In the meanwhile, when plants are young, they would die unwatered. In that situation I would have to begin all over again, so that would be waste as well. So, to water in an economical way in order to keep the plants alive and growing seems to me a rational thing to do. But how to do this right, is certainly a complicated matter involving the plant, the soil, the planting techniques, the microclimate, the watering system etc.
Hobbygardener (MGS member) with a rooftop garden in Basel and a garden on heavy clay with sand 600m from seaside in Costa Blanca South (precipitation 300mm), learning to garden waterwise