Different questions
pH describes acidity at sampling; alkalinity describes acid-neutralizing capacity and often drives pH drift and treatment demand. Do not select acid or dose from pH alone. Use qualified design and safe handling.
Guide 04 / Irrigation & nutritionMeasure delivery.
Measure delivery.
Protect the roots.
Water and nutrients work through the root zone. Confirm drainage, source-water quality, system uniformity, and crop demand before changing a runtime or fertilizer dose.
No universal scheduleCrop stage, weather, rainfall, soil or substrate, canopy, salinity, emitter layout, and local water quality change every program.
01 / Water and roots
Interpret the whole sampleAir first.
Air first.
Then chemistry.
A lab result is useful only when matched to source, season, method, soil/substrate, drainage and crop response. Sample each source correctly and retain method and units.
Track the salt load
Electrical conductivity is a proxy for dissolved salts, not their identity. Compare source, delivered solution, and root-zone or drainage trends using consistent methods; poor drainage concentrates risk.
Look beyond total EC
Specific ions can affect plants, soil structure, or leaf tissue even when a single summary number appears acceptable. Consider sodium adsorption context, chloride, bicarbonate, crop exposure, and leaching feasibility with a local specialist.
Root-zone rule: correct ponding, compaction, blocked drainage, unsuitable media, and chronic saturation before increasing fertilizer. Dragon fruit roots need both moisture and oxygen. Generic thresholds are not a substitute for a laboratory's crop- and soil-specific interpretation.
Control and protect
Document source, pump, backflow protection where required, pressure regulation, flow meter, isolation valves, fertilizer injector safeguards, and sample points. Keep current schematics.
Match the hazard
Choose and maintain filtration for source sediment and biological load plus emitter requirements. Record differential pressure and clean or backwash by validated criteria.
Group similar demand
Separate pressure or elevation differences, soil types, crop stages, and incompatible operating demands. Confirm each zone's design flow before adding emitters.
Measure uniformity
Collect timed output from representative emitters at near, middle, far, high, and low points. Compare pressure and flow, investigate outliers, and repair before extending runtime.
| Frequency / trigger | Check | Record and response |
|---|---|---|
| Each irrigation | Source status, controller, leaks, runoff or ponding, zone pressure and flow against baseline | Date, zone, start/stop, meter volume, rain, anomaly, person |
| Routine field sample | Timed emitter outputs across hydraulic positions; wetting depth and lateral spread | Locations, collection time, volumes, average, low emitters, repairs |
| Filter trigger | Pressure differential or manufacturer/validated criterion | Before/after pressure, cleaning action, waste handling |
| Seasonal / source change | Water analysis and source variability | Laboratory, method, units, interpretation, trend and approved action |
02 / Water & salinity lab
Lab trends · cautious interpretation · drainage firstWater tests.
Water tests.
Trends, not thresholds.
Track trends in pH, EC, alkalinity, Na, Cl and SAR across source, solution and root-zone samples. No single number prescribes action; interpretation needs method, units, soil/substrate, drainage, cultivar and season — confirm with lab or adviser. Fix ponding and blocked drainage before chasing chemistry.
Lab interpretation required: generic thresholds are not a substitute for a laboratory's crop-, soil- and water-specific advice. Retain method, units, sampling point, date, and prior trend. Do not dose acid, gypsum or leaching volume from an online table alone — confirm with the reporting lab and a local specialist.
pH — snapshot, not capacity
pH describes acidity at sampling. It shifts with CO2, temperature, time and alkalinity. Track pH together with alkalinity and lab method; a target pH is meaningless without the water's buffering load and the soil or substrate response.
EC — total salt proxy
EC estimates total dissolved salts, not which salts. Compare source EC, delivered fertigation EC and root-zone or drainage EC using consistent units (dS/m) and meters. Rising root-zone EC with limited drainage concentrates risk even if source EC looks modest.
Alkalinity — drift driver
Alkalinity (often bicarbonate) measures acid-neutralizing capacity and usually drives medium pH upward and acid demand. High alkalinity may push pH drift despite a “normal” pH reading; design of acid injection, handling and safety needs qualified engineering.
Na & Cl — ion-specific stress
Specific ions can injure roots, stems or leaves and degrade structure even when EC alone appears acceptable. Track Na, Cl, Ca, Mg and bicarbonate together; note sampling position (emitter, drainage, leaf) and crop exposure history rather than judging from total EC.
SAR — infiltration context
SAR relates Na to Ca+Mg to flag sodium hazard to soil permeability. It is conceptual: unchanged water may behave differently in sand vs clay, with organic matter, rainfall or gypsum history. Use the lab's SAR class plus infiltration observations, not a single ratio, to discuss risk.
Compare the series
Plot source, input and drainage EC, pH, Na and Cl by date and season using one lab's method. Seasonal shifts, lab change, dilution by rain or concentration by poor drainage explain jumps better than any one result.
Do not pick acid from pH alone
Two waters at pH 7.8 can need very different acid volumes if alkalinity differs tenfold. Request bicarbonate/alkalinity and discuss safe injection design; acid is a handling and crop hazard.
Layer ECs together
Keep four EC traces: source at bore/tap, delivered solution at injector discharge, drainage or suction lysimeter, and substrate/soil extract where a validated method exists. Divergence points to accumulation, dilution or emitter error.
Watch the ions
Cl may accumulate in leaf margins; Na affects structure and uptake. If Na or Cl trend upward, check source variability, fertilizer salt load and leaching feasibility before adding more product.
Water ≠ rooting method
Resources 88–92 contrast water-rooting cuttings vs true air layering for multiplication. Holding cuttings in water for roots risks rot and labeling chaos and does not replace substrate callus and air-layer hygiene. Keep nursery water quality separate from field irrigation chemistry; also align with soil preparation & drainage and clean cutting QA.
Prep before chemistry
Drainage, structure, organic matter and emitter uniformity set how salts move. Without air in the root zone, even good water becomes a salt trap. Confirm drainage, ponding and uniformity first, as emphasized in field planning and the foundations medium sections.
Sensitivity varies
Dragon fruit cultivar and rootstock sensitivity to salinity, Na and Cl are not uniform in published guides. Treat any listed tolerance as hypothesis; compare block response under the same water and drainage rather than assuming one threshold fits all.
Chain the sample
Label every sample with source, tap vs tank vs drainage, date-time, sampler, lab, method, units and prior irrigation. Without chain, two labs' numbers are not comparable and trend is lost.
02A / Salinity mitigation — drainage before dose
Leaching is a fraction, not a prescription
Leaching moves salts below the root zone when water extra to crop need drains freely. The leaching fraction — drainage ÷ applied — is an observed ratio, not a product dose. Without free drainage it becomes ponding.
No drain, no leach
Verify profile drainage, outlet function, slope and substrate permeability first. Correct compaction, blocked outlets, fine-textured pockets and perched layers before calculating any extra water. In containers or heavy ground, excess water without exit worsens anoxia.
Uniformity is salinity control
Poor distribution concentrates salts in under-watered spots while leaching elsewhere. Collect timed outputs from near, middle, far, high and low points; compare pressure and flow, repair outliers and confirm uniformity before adjusting runtime for salts.
Where salts hide
Salts accumulate at wetting fronts, pot edges, ridge tops and beneath drip lines without adequate spread. Inspect cores and crusts at those positions; a single composite can hide the hot spot.
Use rain, plan for dry
Seasonal rain can dilute and move salts seasonally; dry, hot, windy periods concentrate them. Log rainfall with irrigation meter totals to separate concentration from source change.
Exposure windows
Young, newly rooted plants, flowering and fruit-fill stages may show stress earlier under the same EC/Na/Cl exposure. Track stage, canopy cover and response history rather than applying one flat allowance.
No field prescription here
This lab is educational. Any leaching program needs lab interpretation, soil, drainage and environmental compliance checks specific to your site. Do not set a leaching routine from a calculator alone.
02B / Practical checks — sample, meter, filter
Take the sample correctly
- Sample each source separately after stable pumping; flush taps/tanks first
- Use clean, lab-specified containers; fill, cap, label and chill per method
- Record collection point, time since fertilizer injection, and rain
- Include delivered solution and drainage where a validated method exists
- Keep method and units; do not compare mg/L to meq/L without conversion
Calibrate, rinse, verify
- Calibrate EC and pH meters with dated standards at field temperature
- Rinse probe between samples; check cell fouling and cable integrity
- Cross-check field meter against lab periodically; log drift and replacement
- Clamp negatives; a negative EC or pH outside 0–14 signals error not water
- Treat continuous sensor traces as guidance, not a certified lab result
Protect emitters
- Size filtration to source sediment/biological load plus emitter requirement
- Log differential pressure; clean/backwash by validated trigger, not calendar
- Handle incompatible fertilizer mixes that precipitate and blind filters
- Retain schematics and sample points for diagnosis after failures
- Link filter maintenance to uniformity checks — fouling shows as flow loss
Advisory helper — no prescription
Salinity helper: ECw & leaching context
Enter your source water EC (dS/m) and either a target leaching fraction or a drainage EC threshold you are monitoring with your lab. Output is advisory context only — it does not prescribe water, acid, gypsum or fertilizer. Drainage, uniformity and compliance must be verified on site.
Advisory output
Enter ECw and either LF% or a threshold you monitor with your lab, then calculate for an advisory leaching context and next checks.
Educational illustration only. Leaching need depends on source variability, soil or substrate, drainage, cultivar, stage, rainfall and local rules. Confirm with your lab and adviser before changing water or inputs.
Filter by issue — accessiblePick the symptom.
Pick the symptom.
Find the next check.
Eight decision cards organize next checks by water-quality issue. Buttons use aria-pressed and a live status; cards carry data-issue and hide with .hidden. Advisory only — confirm with lab.
Showing 8 decision cards — filter: All issues.
Rising EC in drainage
Drainage EC trending up while source is stable suggests salts accumulating. Check drainage outlet, uniformity, rainfall vs meter totals, and salt load from fertilizer before adjusting water.
- Next check
- Compare source, delivered, drainage ECs; inspect wetting front and crust positions
- Risk if ignored
- Root-zone concentration, tip burn, reduced uptake
- Consult
- Lab trend + drainage feasibility
Source EC variable
Source EC swings with season, tide, pumping depth or source switch. Log source separately from delivered solution; do not average away a spike.
- Next check
- Date source samples; plot EC vs rainfall/pumping log
- Action cue
- Discuss blending feasibility only if lab and supply allow
- Watch
- Fertilizer EC adds on top — delivered EC is higher
pH high, alkalinity high
Medium pH drifting up despite “normal” input pH often tracks alkalinity load. Do not dose acid from pH alone; request bicarbonate and discuss qualified injection design and safety.
- Next check
- Alkalinity/bicarbonate, lab method, injection point safeguards
- Watch
- Acid + incompatible fertilizers precipitate and block emitters
- Consult
- Engineer + lab — handling risk
pH high, alkalinity low
Low alkalinity water has little buffer; pH may swing with CO2 or fertilizer. Calibrate meter, verify time-to-read, and compare to lab pH at same temperature.
- Next check
- Repeat with calibrated meter; compare field vs lab pH
- Watch
- Sensor fouling mimics drift — rinse and standard-check first
- Consult
- Lab on method and timing
Na high, structure declining
Infiltration slowing, crusting or ponding with elevated Na hints sodium hazard. Review SAR discussion, Ca/Mg levels, rainfall history and physical drainage before any amendment.
- Next check
- SAR context, texture, crust observation, drainage outlets
- Watch
- Amendment without drainage is wasted
- Consult
- Lab + soil adviser — no online gypsum rate here
Cl high, tip injury
Tip burn, marginal necrosis or leaf Cl rise may reflect Cl exposure from source or product. Track Cl by source, tissue method and stage; check fertilizer chloride contribution.
- Next check
- Source Cl, product label Cl, tissue trend vs stage
- Watch
- Cultivar stage sensitivity varies — compare same block history
- Consult
- Lab tissue interpretation
Very low EC — low buffer
Very low EC water (e.g., rain-fed or RO) has little buffering and can swing pH with injection. It is not “pure is always good” — media nutrition and pH stability depend on balanced supply, not near-zero salts.
- Next check
- Fertigation EC at dripper, media EC trend, pH swing log
- Watch
- Over-injection risk when background EC is tiny — verify arithmetic twice
- Consult
- Nutrition plan review
Trends diverge — diagnose
Source stable but root-zone variable? Or uniformity collapse hiding extremes? Map spatial EC: near vs far emitters, wetting front vs pot center, drainage vs input. Composite sampling hides hot spots.
- Next check
- Spatial EC grid + uniformity catch-can test
- Watch
- Meter vs lab divergence — cross-check standards
- Consult
- Trend table with method and units retained
| Sample point | When & method | Record |
|---|---|---|
| Source (bore/tap/reservoir) | After stable pump; lab container; date-time | EC, pH, alkalinity, Na, Cl, Ca, Mg, SAR remark, lab, units |
| Delivered solution at injector | Mid-injection; note product and rate | Delivered EC/pH vs calculation; compatibility note |
| Drainage / lysimeter | Representative outlet; time since irrigation | Drainage EC, LF observed (drained ÷ applied), trend vs source |
| Field meter check | Daily/weekly with standards | Meter EC/pH vs standard, rinses, fouling, operator |
Link checks: confirm drainage and uniformity per field planning — soil prep & drainage, hygiene per propagation QA (callus vs water hold 88–92 caution), and stage response per crop care. No single EC, pH or SAR value here is a prescription.
03 / Scheduling
A feedback loop, not a timerObserve demand.
Observe demand.
Verify the result.
Choose a starting volume from local experience and measured wetted root volume, then adjust with evidence. Fixed daily or weekly schedules can overwater after rain and under-supply during hot, windy crop-fill periods.
Read stage and weather
Note establishment, vegetative growth, flowering, fruit load, canopy size, temperature, radiation, wind, humidity, rainfall, and forecast. Crop coefficients or evapotranspiration estimates require local calibration.
Inspect moisture and air
Use soil feel, cores, tensiometers or suitable sensors at representative depths and positions. In substrate, track input, drainage fraction and EC only under a locally validated approach.
Convert need to runtime
Use measured emitter flow, operating emitter count, and target volume. Account for rainfall and shut down where water ponds, bypasses roots, or drains excessively.
Close the loop
Recheck wetting pattern, drainage, pressure, plant status and meter totals. Change one documented factor at a time so block response remains interpretable.
Runtime calculator
Volume into operating time
Assumes every entered emitter operates simultaneously at its stated liters-per-hour flow. “Plant/post” is the management unit receiving the target volume. Area is recorded for context and does not alter the arithmetic.
Total target volume800 L
Zone flow400 L/h
Calculated runtime2 h
Calculation only; verify measured zone flow and wetting response.
Product mass converter
Nutrient mass into fertilizer mass
This arithmetic converter is not a nutrient recommendation. It assumes the guaranteed analysis percentage represents the desired nutrient on the same mass basis and the product is otherwise suitable and lawful.
Calculated product mass5 kg
Product mass per hectare5 kg/ha
Check whether the label expresses elemental nutrient or an oxide form before using this conversion.
04 / Nutrition
Feed objectives, not symptomsSample first.
Sample first.
Split and verify.
Build a locally calibrated plan from soil or substrate tests, irrigation water, consistently sampled leaf or stem tissue where a valid interpretation exists, crop removal, growth, crop load, and response history.
Roots and controlled growth
Avoid concentrated salts near a small root system. Establish drainage and uniform water first; confirm new growth before increasing inputs.
Build sound canopy
Support steady stems without excess succulent growth, shading, delayed maturity, or imbalance. Review nitrogen alongside all other nutrients and water.
Maintain balance
Use analysis and crop history rather than a “bloom booster” assumption. Avoid abrupt salinity or water shifts during sensitive reproductive stages.
Support crop load
Match supply to measured demand and expected removal while protecting roots. Track fruit quality, vegetative response and residual salts.
Reassess and replenish
Review yield, removed biomass, leaf or soil trends, drainage and next-cycle objectives before replacing nutrients by formula.
Reduce peaks and losses
Smaller, monitored applications can better match uptake than large infrequent doses, but frequency must fit soil retention, rainfall, irrigation design, labor and environmental rules.
Protect people and water
Use required backflow prevention, compatible equipment, agitation where appropriate, calibrated injection, clean-water flushing, secure storage, and records. Never mix products without compatibility confirmation.
Watch the combined solution
Source water plus fertilizer determines delivered EC and chemistry. Concentrated calcium with phosphate or sulfate sources, pH shifts, and incompatible products can precipitate, clog emitters, or create hazards.
Symptom caution: yellowing, reddening, weak growth, necrosis, corking, tip injury, or poor fruit set are not unique deficiency or toxicity diagnoses. Root damage, saturation, drought, heat, cold, salinity, pH, pests, disease, spray injury, crop load, and nutrient interactions can look alike. Confirm roots, distribution, records, and appropriate analyses before correcting.
Block monitoring checklist
- ContextDate, block, cultivar, stage, canopy or crop load, weather and rainfall.
- IrrigationZone, runtime, meter volume, pressures, representative emitter outputs and wetting observations.
- Root zoneMethod, sampling position and depth, moisture, drainage, ponding and root condition.
- InputsProduct label, lot, guaranteed analysis, actual mass, tank volume, injection start/stop and flush.
- AnalysesSample ID, method, units, laboratory, interpretation source and comparable prior results.
- ResponseGrowth, symptoms, yield or quality, corrective action, person and recheck date.
05 / Selected sources
Wikifarmer / WaterWater requirement and irrigation systemsProduction context to adapt and verify locally.Wikifarmer / FertilizationDragon fruit fertilizationStage and nutrient-management context, not a universal formula.Cal Poly PomonaDragon fruit plant careSoil, water and fertilizer overview.Peer reviewedOptimization of fertilizer dosesSite-specific experimental evidence; treatments are not universal rates.Peer reviewedIntegrated nutrient managementResearch on combined nutrient strategies and crop response.