Farkesht training
Watering trees correctly, from diagnosis to a written schedule
Most trees lost in an orchard were not thirsty. They drowned, or the water went in somewhere no root was working. This page draws what happens under the soil — and then says where the rest of the skill is taught, lesson by lesson.
- Depth holding most of the absorbing roots
- 60cm
- Root spread against the canopy radius
- 150%
- Minimum share of the ground to wet
- 33%
Updated September 1, 2026Farin Kesht Taban Co.
Chapter one
A tree tells you before it dies
The difficulty is that a drowned tree and a thirsty one say almost the same thing: both yellow, both drop leaves, both shed fruit. A grower who reads the first as the second waters harder and finishes the job.
Too much: the roots suffocate
Roots need air. When the pore space stays full of water, a root drowns long before it goes thirsty — and the tree above it shows every sign of thirst.
- Yellowing that starts on the lower, inner leavesboth
- Green, healthy leaves dropping without yellowing first
- A sour, stagnant smell in the soil at the trunk
- Dark, damp, softening bark at the collar
- Algae, moss or fungal growth on the soil surface
- Fruit splitting after a heavy irrigation
Too little: drought stress
A tree stops growing before it wilts. Short annual shoots and small fruit report the problem well before a single leaf scorches.
- Yellowing from the leaf margin inwardsboth
- Midday wilt that recovers by evening
- Scorched, dry leaf tips and margins
- Short current-season shoots
- Undersized fruit and a light cropboth
- Leaf drop well before autumn
Stop reading the canopy. Open the soil.
Two days after an irrigation, at the edge of the wetted area and well clear of the trunk, open the soil to these three depths. Still dry at 60 cm and the water was short; still muddy at 15 cm and it was too much. This is the only test that separates the two columns above.
Chapter two
The roots that drink are not at the trunk
Water has to reach the feeder roots: a band under the canopy edge, in the top half-metre of soil. Every litre delivered outside that band either evaporates at the surface or sinks past the roots entirely.
- 80%
- Absorbing roots in the top half-metre
- 60cm
- Effective rooting depth, mature tree
- 150%
- Root spread against the canopy radius
- 50cm
- Nearest emitter to the collar
The structural roots go deeper, but the work of taking up water and nutrients is done by fine hairs near the surface.
Every volume calculation closes on this depth. Water below the line is not coming back up.
Roots run past the dripline, which is why wetting only around the trunk leaves half the root system dry.
This clearance is a disease decision, not a hydraulic one: a permanently wet collar is the way Phytophthora gets in.
Three ways to get it wrong, one way to get it right
All four growers below ran water for an hour. From the surface their work looks identical. What they built underground is not.
common mistake
Water at the trunk
The column sinks beside the collar and straight past the feeder roots. Result: a permanently wet collar and roots that are still thirsty.
common mistake
Short, frequent runs
The water wets a film and stops well above the roots. The tree learns to root in those few centimetres, and the first real heatwave takes it down.
common mistake
Long, heavy runs
The water goes past the root zone and takes the soluble fertiliser with it. It shows on neither the water bill nor the leaf — until next year’s growth is short.
correct
Under the dripline, to rooting depth
Two overlapping wetted bodies under the canopy edge, stopping at that half-metre and no deeper, with dry soil around the collar. That is the whole rule; everything else is execution.
Your soil decides your emitter spacing
A litre of water makes a different shape in every soil. Emitters have to be close enough for those shapes to touch — otherwise a dry strip is left between two wet ones, and roots will not cross it.
Sandy soil
Water sinks fast and spreads little; the bulb is narrow and deep. More emitters, each at a lower flow rate.
Emitter spacing40 cm
Loam
The balanced case — lateral spread and vertical movement roughly equal. Most design tables assume this soil.
Emitter spacing60 cm
Clay soil
Water enters slowly and spreads wide; the bulb is shallow and broad. Low flow over a long run, or it simply ponds and runs off.
Emitter spacing90 cm
Chapter three
How much? A calculation, not a guess
The volume for each irrigation comes out of four measurable numbers: reference evapotranspiration, the crop coefficient, the canopy area the tree actually shades, and the efficiency of the system. The rest is arithmetic.
Water required per tree per day
V = ET₀ × Kc × A ÷ Ea
- 16 m²
- Canopy area of the worked example
- 90 %
- Application efficiency, localised system
- 144 L/day
- Daily requirement at the summer peak
- 269 L
- Readily available soil water in the wetted zone
The figures here are this page’s worked example, so the chart in the next chapter can be reproduced: one mature tree with a sixteen-square-metre canopy in a semi-arid climate. Put in your own four numbers and you get your own curve.
- 01
Measure the canopy area
Take the canopy diameter in two perpendicular directions, average them and work out the area of the circle. That figure is the tree’s own field.
One square-metre figure per age class in the orchard
- 02
Get daily demand from ET₀ and Kc
Take reference evapotranspiration from the nearest station and multiply it by that month’s crop coefficient. The result is the depth of water used, in millimetres per day.
Millimetres per day, for every month of the season
- 03
Turn depth into litres
Multiply the depth by the canopy area for the daily volume in litres, then divide by the system’s efficiency to get what actually has to enter the pipe.
Litres per day, per tree
- 04
Get the interval from soil storage
Divide the readily available water in the wetted zone by the daily use. That is how many days you can wait — not the number that worked last year.
An irrigation interval for each month separately
- 05
Get run time from emitter flow
Divide the volume per irrigation by the combined flow of the emitters on that tree. If the answer runs past a few hours, you are short of emitters, not of time.
Hours and minutes, settable on a timer
- 06
Confirm it with a spade, not a clock
A day after irrigating, dig at the edge of the wetted area down to rooting depth. If the wetting front has stopped exactly there, the calculation was right. Higher or lower, and the run time needs correcting.
Wetting front matching the effective rooting depth
Chapter four
One tree, twelve irrigation schedules
The tree that wants water every second day in midsummer gets by on one irrigation a month in late autumn. "Once a week, all season" means over-watering for half the year and under-watering for the other half.
- Mar: 27 L/day — 10 days
- Apr: 56 L/day — 5 days
- May: 99 L/day — 3 days
- Jun: 135 L/day — 2 days
- Jul: 144 L/day — 2 days
- Aug: 122 L/day — 2 days
- Sep: 82 L/day — 3 days
- Oct: 42 L/day — 6 days
- Nov: 18 L/day — 15 days
- Dec: 9 L/day — 30 days
- Jan: 7 L/day — 30 days
- Feb: 14 L/day — 19 days
- Bud break
- Growth and fruit set
- Ripening and harvest
- Dormancy
- Peak demand
Bud break
The soil still holds winter moisture and the roots have only just started work. A heavy early irrigation here suffocates roots in cold, saturated soil rather than helping them.
Growth and fruit set
The most sensitive window of the year. Any drought stress in these months lands directly on fruit size and on next year’s flower initiation. A short, steady interval matters more than a large volume.
Ripening and harvest
A gradual, controlled reduction — not a sudden cut. Sharp swings in soil moisture at this stage split fruit and shed it.
Dormancy
Irrigation is reduced, not stopped. One or two heavy winter irrigations protect the roots from winter drought and, on saline ground, push accumulated salt below the root zone.
Chapter five
Where on the ground does the water go?
The four layouts actually built in orchards, seen from above. They differ in two things: how much of the soil under the canopy gets wet, and whether the trunk is left standing in it.
Full basin (flood)
The whole area under the canopy, collar included, goes under water. Maximum wetting and the simplest thing to build — and the only layout that stands the trunk in water by design.
- Ground wetted
- 100 %
- Outlets per tree
- none
collar sits in water
Ring basin
The same basin with a dry middle. A bund around the collar holds the water in a ring under the canopy edge. With no equipment whatsoever, it fixes the basin’s one real fault.
- Ground wetted
- 55 %
- Outlets per tree
- none
collar stays dry
Drip, two laterals
Two lines either side of the row, with emitter spacing taken from the soil texture. The lowest water use and the finest control — given correct filtration and periodic flushing.
- Ground wetted
- 35 %
- Outlets per tree
- 8
collar stays dry
Bubblers
Four high-flow outlets in the four quarters of the canopy, each in its own small basin. On large trees and heavy soils it fills faster than drip and clogs less.
- Ground wetted
- 45 %
- Outlets per tree
- 4
collar stays dry
Turning a traditional basin into a ring is the cheapest correction available in an orchard: no equipment at all, just moved soil, and the collar comes out of the water.
Chapter six
The Farkesht tree irrigation course
What you have read so far is the map. The course walks the same route with a camera in the orchard: real measurements, the calculation on paper, and the layout built on a living tree.
Growers with a bearing orchard
You know the tree; what is missing is the number. This course turns that experience into a schedule you can set on a timer.
Newcomers and young orchards
An orchard’s most delicate years are its first three. The course starts at the whip: where to put the water, how much, and when to grow the wetted zone with the roots.
Installers and system designers
Flow rates, emitter spacing, block division and run times — the things that separate a system that was installed from one that works.
What the course covers
Every module ends in something you can do, not something you can define. If you finish a module unable to do the thing written beside it, that module has not done its job.
- 01
Diagnosis: reading the tree and the soil
The symptoms of too much and too little water, telling them apart from nutrient deficiency and disease, and the spade test — where chapter one of this page left off.
Diagnose your own orchard’s moisture state with certainty
- 02
Soil: texture, storage and infiltration
Determining texture by hand without a laboratory, measuring infiltration rate with a simple ring, and estimating readily available water in the root zone.
Estimate your orchard’s soil water storage in litres
- 03
Calculation: from ET₀ to litres
Finding local ET₀, choosing the right crop coefficient for the species and growth stage, and arriving at a daily volume per tree.
Build a monthly water requirement table for your orchard
- 04
Scheduling: interval and run time
Turning volume into an interval and a run time, adjusting the schedule month by month, and correcting it for rainfall and heatwaves.
Write a twelve-month irrigation calendar you can follow
- 05
Execution: emitters, filters and blocks
Choosing outlet type and flow rate, spacing by texture, dividing the orchard into simultaneous blocks, and maintaining filters and flushing lines.
Design the layout and the flushing routine for your system
- 06
Seasons: from bud break to dormancy
Managing water through flowering, fruit set, harvest and winter; leaching irrigations on saline soils, and the winter irrigation.
Match the schedule to the tree’s growth stage
- Sectioned curriculumEach course is divided into sections and lessons, so you can go straight to the part you need.
- Pick up where you left offProgress is saved per lesson and the player resumes from the point you stopped.
- Free preview lessonsSome lessons are open before purchase, so you can judge the depth and the tone first.
- Permanent accessA course you buy stays open in your account. There is no time limit on watching it.
- Phone or desktopThe player runs in the browser. Nothing to install.
- Ask an adviserStuck anywhere along the way, post the question in the forum and get an adviser’s answer.
Courses available now
This list is read straight from the Farkesht library — every course published appears here.
- Pistachio
مراقبت فصلی باغ پسته
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- 1 lessons
- 12:00
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- Almond
سرمازدگی و گلدهی بادام
انتخاب رقم دیرگل، تغذیه بور قبل از گل، و کارهایی که بعد از سرمای دیررس بهاره هنوز باغ را نجات میدهد.
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- Pomegranate
ترکیدگی میوه و کرم گلوگاه انار
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ثبت آبیاری، تغذیه و سمپاشی طوری که فصل بعد قابل مقایسه باشد. این درس به گونهٔ خاصی وابسته نیست.
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Chapter seven
Plans and how to get in
There are two routes to these lessons: buy the single course you need, or take a plan that opens the whole library at once.
Buy one course
You buy a course and it stays open in your account permanently. Right when you know exactly which subject you need.
See courses and pricesFarkesht plan
Opens every video course, the technical knowledge base and the species files together — and any course published while the plan runs is included too.
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Basic
Register your orchard and keep its record
150,000 Toman90 days
Includes
- Ask questions in the forum
- Orchard records and care sheets for your species
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The expert knowledge base, and every species
350,000 Toman180 days
Includes
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- Orchard records and care sheets for your species
- Care sheets for every species
- Expert knowledge base
- Recorded video courses
Complete
Everything, for a year
600,000 Toman365 days
Includes
- Ask questions in the forum
- Priority placement for your questions
- Orchard records and care sheets for your species
- Care sheets for every species
- Expert knowledge base
- Recorded video courses
- Private consultation with an agronomist
Questions
Common questions about watering trees
The eight asked most often in the forum.
How many days between irrigations?
There is no fixed number, and any answer given without knowing your soil and climate is a guess. The interval comes from dividing readily available soil water by the tree’s daily use; the same tree may want water every second day at the summer peak and every twenty days in autumn. The chart in chapter four shows exactly that.
How much water each time?
Enough for the wetting front to reach the effective rooting depth — about sixty centimetres on a mature tree — and no further. The volume comes from V = ET₀ × Kc × A ÷ Ea, and is corrected after the first run with one check hole.
Do trees need irrigating in winter?
Yes, but rarely and heavily. One or two winter irrigations in the rainless months protect the roots from winter drought and, on saline soils, carry accumulated salt below the root zone. Cutting water entirely through a dry winter is one reason shoots die back in spring.
How does watering a young tree differ?
Smaller volumes, more often, and a much smaller wetted area. A young tree’s roots have not left the planting hole, so the water has to stay there — but that area must be grown every year with the roots, or a mature tree ends up with a sapling’s root system.
The leaves are yellowing — too much water or too little?
The canopy cannot settle it, because both states yellow. The pattern is a clue — over-watering usually starts on the lower, inner leaves and drought at the leaf margin — but the answer comes from the soil: two days after irrigating, dig to sixty centimetres at the edge of the wetted area.
Do I have to convert a traditional basin to drip?
Not necessarily. If budget or water does not allow it, turning the basin into a ring with a bund around the collar fixes its biggest fault at no equipment cost at all. Drip earns its price when water is limited or when you want to fertigate.
Can I write a schedule from this page alone?
The framework is here and it is enough to start. What a page cannot give you is practice at measuring: judging soil texture by hand, running an infiltration test, choosing the right crop coefficient for the species and stage. That is precisely what the video course shows, in the orchard.
How do I get access to the courses?
Buy a course individually and it stays open in your account permanently, or take a plan and open every course plus the knowledge base and species files for as long as the plan runs. Some lessons are also open as free previews before you buy.
Take the guesswork out of your orchard’s irrigation
Start with the video course — or, if you want an adviser looking at your own orchard, request a consultation.