What's wrong with my plant? - Iron Deficiencies

What's wrong with my plant? - Iron Deficiencies

With winter in full swing, our phone has been going crazy with gardeners experiencing gardening issues.

In short, the most common problem this time of year is the temperature once corrected most issues will solve themselves. Always double check your lights on temperature and humidity and the same thing goes for lights off.

Lights ON Temperature 24c - 29.5c Degrees

Lights OFF Temperature 19.5c – 22c Degrees 

Once lights go off humidity generally rises, employing the use of heaters and/or dehumidifiers will negate this. High humidity can also antagonise Iron, always check your numbers.

  • An Insufficient amount a food, low EC
  • pH instability, impacting nutrient availability
  • Excess food causing a lock out of nutrients, high EC
  • Temperature, humidity & Environmental factors (HVAC)


Iron deficiencies are most commonly witnessed in colder weather, the cause of this is when the temperature of the root-zone goes below 15c degrees this has a major effect on plant metabolism and, in most cases, will inhibit nutrient absorption and cause nutrient deficiencies.

Iron deficiencies lack the green pigment in between leaf segments, veins remain green and the leaf will start to look chlorotic, chlorotic growth lacks the green pigment (chlorophyll) that makes the leaf tissue look green.

Seedlings can present an Iron & Nitrogen deficiency early on if feeding is introduced too late.

Iron Information: 

  • Nitrogen is reliant on iron as its role in Nitrogen fixation.
  • Most commonly used as a Chelating agent in Hydroponic Cal/Mag Solutions.
  • Iron is a mobile micronutrient.
  • Ideal pH range for Iron in Hydroponics or Coco (Fe) 5.6-6.5
  • Ideal EC recommendation 0.2-0.7 (Relative to growth)
  • Best Temperature for Iron availability 18.5c – 22c degrees
  • Low RH% (Humidity) Increases micro-nutrient availability, uptake & translocation.
  • Micro-nutrient used in the largest quantity.


The most abundant form of Iron in soils is ferric oxide (Fe2O3) or hematite, which is an extremely insoluble form of iron and imparts a reddish colour to the soil.


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