As a farmer/grower of sick cannabis plants, the ultimate objective is to grow healthy and productive plants. Having a great product producing a higher yield translates to increased finances. The trick to growing healthy cannabis is just by providing adequate light, proper watering, the right climate conditions needed by that certain strain, and lastly, providing proper nutrients.

For all growers, nothing is more disastrous than having sick cannabis plants. Monthly and Annual production targets are usually derailed once your plants get sick. The most common of these is nutrient deficiency. This lack of nutrients would make the plant more prone to insect infestation, mold, and stunted growth. In extreme deficiencies, the plant or plants may eventually die.

There are various nutrient deficiencies and there are also ways to identify this ahead of time so you may arrest the spread of the problem and continue to grow healthy plants. 

ph Levels in Both Soil and Water

Before you start identifying nutrient deficiencies in your plants, it is best to start by checking on the pH level of both your soil and water used to hydrate them. Plants get their nutrition mainly through their roots of sick cannabis plants. If the soil or water is too acidic or alkaline, this leads to improper root absorption, thus nutrients present in both soil and water are not sufficiently taken in by the plant through their roots. Over-fertilizing is one common cause of increasing the pH levels of your plants.

The ideal pH level for your soil and water should range between 5.8 to 6.8.

Signs Of Nutrient Deficiencies in Sick Cannabis Plants

Deficiencies in your pants to tell whether you have a sick cannabis plant or not is easily observable. The three common nutrient deficiency symptoms are as follows:

  • Discoloration – this is the lightening of the color of the leaves. green is healthy in most cases, yellow-green to yellow is not.
  • Drooping – the curling or sagging or leaves which eventually falls off.
  • Low Yield – although this is a late symptom indicating a sick cannabis plant, this could still be remedied, or better, prevented. Early detection is the key.


NITROGEN – the most common deficiency in cannabis. symptoms show a lightening of the leaves, these eventually turn into yellow then it falls off.

PHOSPHORUS – although quite uncommon, its effects lead to shorter, stunted plants and poor yield. Once the petioles of the older leaves turn purple, and leaves turn dark bluish-green, this is most likely a sign of this deficiency.

POTASSIUM – this nutrient is very important in root growth, production of sugars and carbohydrates, and water absorption. without this nutrient, the plant will not grow. Indicators are the browning of leaf tips and the presence of brown spots on the older leaves.

CALCIUM – Calcium helps in the flow of sugars and nitrogen all throughout the plant. once new leaves curl up and are distorted, this is most likely an indication of calcium deficiency

MAGNESIUM – plants use magnesium all the time. It is crucial in absorbing energy given by light. Yellowing of whole leaves and yellowing in other tips and margins are signs of this deficiency. the overall appearance of the plant looks weak and droopy, this is caused by the inappropriate supply of energy.

SULPHUR – sulphur is responsible for the plant’s respiration. It also helps in the breakdown of fatty acids and the production of terpenes and oil. Although uncommon in cannabis plants, it is helpful in knowing the symptoms nevertheless. The yellowing of leaf veins is an indication that sulphur deficiency is at the onset.  Once it is too late, other indicators are the slow growth of the plant and flowers are sparse.

IRON – Iron is used as a catalyst for chlorophyll production. deficiencies are caused by high levels of zinc, copper and manganese in the soil. Chlorosis {yellowing) of leaf veins) of new leaves is an initial indicator, then this spreads out to all other leaves of the plant resulting in poor production of flowers.

MANGANESE – this nutrient aids in the use of nitrogen and chlorophyll production and reduces excess oxygen in the plant. As with sulphur and iron, Chlorosis starts with the new leaves and slowly spreads to the older leaves.

ZINC – Zinc promotes healthy stem growth and assists in the retention and formation of chlorophyll for the plant. Alkaline soils are usually the cause of this deficiency. Leaf distortion and leaves turning 90 degrees sideways are indicators of this deficiency.


Prevention is the best solution to avert the plant’s nutritional deficiency. By providing optimal lighting and top quality potting medium from the start, one can expect a healthy growing, productive cannabis plant.