Read the instructions at the bottom of the page to help you use and interpret brix levels:

Brix Tracker

Brix Tracker

Date Time Block/Field GPS No of Trees Brix (%) EC (mS/cm) Weather Treatments Notes

Complete each field, then click Add Entry to record the Brix % in the table. When you are done recording the Brix you can export a CSV to your computer. The table will be available as long as you use the same browser and don't clear your browser history. 

Using Brix to Monitor Macadamia Tree Health

 

 1. Why Monitor Brix?

 

Monitoring Brix gives real-time feedback on the tree’s health and metabolic strength.

  • Brix measures sugar concentration in sap, which is directly linked to:

  • Photosynthesis efficiency (the tree’s energy production).

  • Nutrient density in the plant tissue.

  • Soil microbial health (good soil = better sugar flow).

  • Resilience to stresses (both pests/diseases and environmental challenges).

 

✅ Higher Brix = Stronger plant defences against pests and diseases (biotic stress).

 

✅ Higher Brix = Better drought resistance, salinity tolerance, and cold/heat resilience (abiotic stress).

 

✅ Tracking Brix trends helps you spot problems before you see symptoms.

 

 2. How to Use Brix to Monitor Tree Health

 

What You Need

  • Handheld refractometer (optical or digital) 
  • High-pressure sap press
  • Distilled water and a soft cloth (for cleaning)
  • Notebook or mobile app for recording results 

 

Using Brix to Monitor Macadamia Tree Health

 

 2. How to Use Brix to Monitor Tree Health

 

  • What You Need
    • Handheld refractometer (optical or digital) 
    • High-pressure sap press
    • Distilled water and a soft cloth (for cleaning)
    • Notebook or mobile app for recording results 

 

  • When to Measure
    • Time: 11:00 am to 4:00 pm (sunny weather is best)
    • How often:
    • Every 2 weeks during active growth
    • Weekly during flowering, nut filling, and stress periods

 

  • How to Take a Brix Reading
    • Choose 3–5 healthy, fully expanded leaves from mid-canopy.
    • Avoid stressed, diseased, or shaded areas unless you’re troubleshooting.
    • Crush the leaf with a sap press to extract sap.
    • Place a drop of sap on the refractometer lens.
    • Read the Brix value (in %).
    • Clean the lens with distilled water after each sample.
    • Record each reading, and average the readings per block or field.

 

Using the same method, you can also check Brix on nut sap and EC during the nut development stages.

 

 3. Interpreting Leaf Brix and EC Readings

 

Optimum Leaf Brix Levels

Brix Level

Meaning

Action

< 6 ºBx

Poor energy, weak immune system

Improve nutrition, soil biology, reduce stress

6-9 ºBx

Average health

 Boost photosynthesis with foliars, monitor closely

10–12 ºBx

 Good health

Maintain soil/foliar program

>12 ºBx

 Excellent health

High resistance to pests and stress

 

Optimum Leaf and Nut Brix Levels for Each Growth Stage

Growth Stage

Optimum Leaf Brix

Optimum Nut Brix

Notes

Early Vegetative

8-10

-

Focus on strong canopy growth

Flower Bud Initiation 

 9–11

- 

Support high energy demand

 Full Flowering

 10–12

 -

Critical for pollination success

 Nut Set

 10–12

 7–8

Ensures strong initial nut fill

 Early Nut Fill

 11–13

 8–9

Maximise carbohydrate movement

 Full Nut Fill

 12–14

 9–10

Indicates good oil accumulation

 Nut Maturity

 12–14

 10–11

Best quality and storability

 Pre-Harvest

 12–14

 11–12

Highest nut quality achieved

Pro Tips:

  • Always monitor Brix trends over time, not just single readings.
  • A rising trend means your regenerative practices are working.
  • A falling trend signals a need for immediate action (nutrition, biology, or stress management).

 

 

Optimum leaf sap EC (mS/cm) for macadamias at different phenological growth stages:

Growth Stage

Target Leaf Sap EC

Primary Focus

Key Nutrients Driving EC

Notes

1. Early Vegetative (0–2 yrs)

3.0 – 4.5 mS/cm

Root & shoot establishment

Ca²⁺, Mg²⁺

Avoid overfeeding; ensure good root development.

2. Pre-Flowering (2–4 yrs)

4.5 – 5.5 mS/cm

Canopy growth, bud differentiation

K⁺, Ca²⁺, Mg²⁺

Start ramping up mineral supply for the upcoming reproductive demand.

3. Flowering

5.5 – 6.5 mS/cm

Pollen quality, flower retention

K⁺, B, Ca²⁺

High EC helps support pollination and flower vigor.

4. Nut Set & Early Nut Growth

6.0 – 7.0 mS/cm

Cell division, rapid nut development

K⁺, Ca²⁺, Mg²⁺

Critical phase—Nut abortion is often linked to low EC or K/Ca imbalance.

5. Nut Fill & Oil Accumulation

6.5 – 7.5 mS/cm

Oil synthesis, sugar loading

K⁺, B, Ca²⁺, Mg²⁺

Highest nutrient demand. Maintain consistent moisture & sap flow.

6. Post-Harvest Recovery

4.0 – 5.0 mS/cm

Root flush, energy reserve replenishment

Ca²⁺, Mg²⁺, moderate K⁺

Reduce inputs but support root cycling and canopy retention.

Pro Tips:

  • Sudden EC drops (≥1.0 mS/cm within days) can signal pest attack, water stress, or root dysfunction.

  • EC above 8.0 mS/cm may indicate salt buildup or over-fertilisation, often accompanied by leaf edge burn or tip dieback.

  • Track alongside sap pH: Ideal is 6.2–6.5 at most stages for balanced nutrient uptake.

  • Sap EC is a snapshot of nutrient availability, not total nutrient status like dry leaf analysis.