3 min read

Cannabis Nutrient Testing in Leaves. How to Track Your Grow Cycle Nutrient Levels.

ByTrichome Team

March 16, 2023

Reading Time: 3 minutes

Routine testing of cannabis leaves to track nutrient levels is an important component of monitoring cannabis grows. It eliminates any guessing about the health of your plants and provides the opportunity to properly manage fertilizer and nutrient levels and enjoy the largest and strongest possible yield. Testing cannabis tissue can tell you if your nutrient program is working and diagnose any nutrient-related disorders.

Knowing the Right Cannabis Nutrient Levels

All of us at Trichome are proud and excited to announce that we are ready to unveil a validated nutrient analysis method on leaf tissue material to monitor nutrient levels. Growers want a healthy plant, and we want to make sure they get it. Several factors related to nutrient levels can contribute to less than ideal plant health. There can be a “hidden hunger” that develops when a crop needs more of a given nutrient but has shown no deficiency symptoms. Conversely, elevated nutrient levels can also be problematic. Cells dehydrate and leaf burn becomes evident. In addition, the amount of nutrients added does not necessarily correspond directly to what actually goes into the plant.

Cannabis plants like to select and control what to take in, how much to take in, and when. For example: A hydroponics solution might have a certain amount of calcium, but without regular nutrient analysis, it is impossible to know how much calcium the plant needs to flourish. Since cannabis actively takes in what it needs, the uptake and nutrient levels inside the plant are not exactly proportional to the levels a grower adds. Sending plant material to a lab for testing is the only way to be sure that nutrient levels rest within the ideal levels.

Trichome Analytical’s Elemental Testing

At Trichome Analytical, we split all elemental analysis into two panels on our COA—nutrients vs. heavy metals—so our clients are clear on which elements are a concern for human health & safety, and which can be monitored for plant health and subsequent yield.

Results from nutrient testing can be used to monitor plant health and essential nutrient uptake at various point throughout the cultivation cycle. This can help dial in your nutrient programs for each cultivar.

  • Boron. This helps with the development and growth of root tips. It also encourages plants to absorb calcium and transports sugars within the plant.
  • Manganese. This is a vital component of chlorophyll production and the photosynthesis process. It also aids with enzyme interactions.
  • Zinc. Zinc promotes the development of stems, leaves and branches. The more mature a plant is, typically the more zinc is present and required.
  • Copper. This assists the development of plant proteins and helps with the strengthening of stems and branches.
  • Iron. Iron is important for chlorophyll production. Iron deficiencies often present themselves as a yellowing of the leaves between the leaf’s veins.
  • Molybdenum. This supports nitrogen processing.

Several studies have determined target ranges for levels of nutrients in cannabis leaf tissue as follows:

Bryson and Mills (2014)
Range (ug/g)
Kalinowski et al. (2020)
Range (ug/g)
Landis et al. (2019)
Range (ug/g)
Phosphorus2,400 – 4,9002,600 – 4,3003,100 – 4,400
Potassium18,000 – 24,00021,000 – 34,00015,000 – 30,000
Calcium15,000 – 44,00015,000 – 53,0005,000 – 21,000
Magnesium4,000 – 8,1003,500 – 7,0002,500 – 4,600
Sulfur1,700 – 2,6002,500 – 3,7001,900 – 2,900
Boron56 – 10526 – 9123 – 57
Copper5 – 7.11.6 – 71.8 – 11.4
Iron100 – 15083 – 16959 – 132
Manganese41 – 9367 – 26424 – 72
Zinc24 – 5226 – 5523 – 46

How to Submit Samples for Cannabis Nutrient Testing

In order for a cannabis plant to thrive, it needs several different nutrients and metals. A lab like Trichome Analytical that offers cannabis nutrient testing gives growers clear science-based insights into plant health that can be priceless in the drive to grow the strongest and healthiest crop. Here are the four steps for submitting samples for testing cannabis nutrient levels:

  • Collect the most recently mature leaf (MRML), which is typically three to five leaves down from the growing tip.
  • For a representative sample, take 25 to 30 leaves from five to 10 plants.
  • For diagnostic analysis of problem situations, sample plants individually, taking leaves from the affected portion of the plant, such as a yellowing leaf, for example.
  • Send samples in a paper bag or manila envelope to our lab along with a chain of custody analysis request.

The interval for collecting samples is determined by how quickly the cannabis or hemp plants will complete their growing cycles. Sampling the same group of plants two to three times during their growing cycle is the best practice. You should collect a representative sample of the most recently matured leaves (MRML) at the correct growth stage to compare with survey ranges that correspond to nutrient concentrations found within MRMLs. This is a good reference for how many leaves are necessary for a sample, as well as nutrient survey ranges that indicate where nutrient levels should land for ideal plant health.

If you are interested in getting your cannabis nutrient levels tested or have any questions concerning cannabis testing in general, please reach out to Trichome Analytical for advice or support.