Quote of the Month

There can be no other occupation like gardening in which, if you were to creep up behind someone at their work, you would find them smiling.

~Mirabel Osler






Monday, 17 September 2012

AGC Meeting Tuesday September 12th 2012

IRRIGATION PRESENTATION
Carol Starr


I thought a good topic for discussion this month would be Irrigation because I think we’ve suffered the hottest, driest summer since we arrived nearly 9 years’ ago. 

Our own vegetable production has been a wash out (excuse the pun) and my usual method of sprinkler irrigation rotated round the garden beds at approx 3 weekly intervals has managed to keep plants alive but certainly not thriving. 
Even the prostrate Rosemary - the one plant that could be relied on to give green cover through the summer - has gone yellow because there wasn’t enough rain thru’ the winter.
When we first got here - I had a vision of creating a luscious, green oasis using plants adapted through millenia to cope with the sub-tropical climate. 

I felt quite strongly against using precious and environmentally costly water resources in our arid climate and was convinced that using the right plants in the right place etc. would produce the garden I wanted.
I was inspired to think this might be possible from visiting the now world famous Beth Chatto gardens in East Chelmsford, Essex, the driest part of the UK, and by reading her book. 


She started her ¾ acre Gravel Garden on her former car park as an experiment to see if the SPECIES Mediterranean plants she planted would survive without irrigation, relying totally on annual rainfall.
After the first year her resolve not to water NEARLY collapsed - but she desisted and the results have been astounding. (see book)
The soil she began with loosely resembles the type of soil most of us have to contend with - very stony, limited topsoil and very free draining - precisely the conditions that med. plants prefer.
What she did:-
Average of 20” of rain a year - temps up to 30degC
Plants from Mediterranean area
Planting method:-
Ample watering in after planting and then relying only on rainfall
Ample mulching - gravel and straw in 2nd year - emergent weeds hoed out in first year.

Armed and enthused, though not naive enough to think similar planting techniques could cope with OUR CONDITIONS without any additional water thru’ the summer, I decided not to install irrigation but to use a sprinkler moved around the garden at 2-3 weekly intervals.
I was also further encouraged in my beliefs by reading. 

Heidi Gildermeister’s Mediterranean Garden - a Waterwise Approach - Majorca.
Again, emphasis on soil preparation
Rainfall from 8“ to 40“ a year
Drought tolerant plants from Mediterranean basin
Provision of shade
Use of paths and placement of large boulders for plant roots to tap into trapped moisture

 Olivier Filippi’s book The Dry Garden Handbook. South of France.
This book further confirmed my beliefs though his approach is largely what the farmers do here - trenching.
Again, emphasis on soil preparation
Mediterranean plants - the right plant in the right place.
He suggests planting in 24” dia wide and 8” deep craters/basins to hold, as a rule of thumb, 20-30 litres/plant given at 10-14 day intervals for up to 2 years until plants are well enough established to cope
Water must get down beyond the bottom of the root ball so that the roots go down in search of water rather than stay at the top of the soil thereby making them susceptible to drying out.
Therefore, the message is that deep, infrequent watering, following best-practice planting - is better than a little water delivered frequently. 


Since we can’t all plant the Olivier Filippi way - we haven‘t all got the space and who wants to see craters or basins (but I’m convinced this method would work) around their gardens for up to 2 years? 

And what about if you change your mind and want to add or subtract planting? 
Incidentally he further advocates that plants are propagated and grown using long, ridged pots where their roots are encouraged to go down rather than coil round the pot as they grow.


Carol has compiled a list of drought tolerant plants. Please contact her and she will email it to you. Ed

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