How to solve the phosphorus deficiency
Phosphorus is an essential nutrient for marijuana plants. It’s known that much of the energy that the plant receives from the sunlight is later stored mostly as phosphorus. Afterwards it’ll be used to perform the different metabolic processes – such as photosynthesis – being at the same time a component of the DNA.
- Improved root development
- Better use of the water in the substrate
- Stimulates the resistance and overall health of cannabis plants
- Stronger stems
- Better resistance to frosts, diseases and pests
- The duration of the vegetative period is significantly reduced given the explosive growth produced by a fast root growth. The grower can start the bloom stage of plants much earlier, thus reducing the total time required to harvest the cannabis crop.
- Improved yields and quality of buds and seeds
- It has a direct role in the production of carbohydrates, improving the production of sugars, starches, etc, and thus producing best quality fruits.
Before the phosphorus can be used as nutrient for plants, we must wait for Mother Nature to perform its vital functions in order to take advantage of the raw materials that it offers. Phosphorus is an element classified as macro-nutrient since it directly participates – in large amounts – in the metabolism of all plants and especially in cannabis crops.
The phosphorus cycle is known as biogeochemical cycle, and is a closed cycle which is repeated constantly in a given ecosystem.
Furthermore, a large part of these phosphates present in the substrate are carried away towards the oceans, so all marine flora and fauna is coated in this mineral. Phosphorus returns to the terrestrial environment by two systems; the first one is through seabird or fish droppings, which have previously fed on algae, which have in turn absorbed phosphorus in their organism. The second way is through both the earth-movings that emerge from the sea or shifting of tectonic plates, although this processes take thousands of years.
The phosphorus cycle
When this element moves from older to younger leaves, the former show chlorosis, turning yellow. The oldest and lowest leaves of the plant perform the function of nutrient reserve which will be used by the plant if necessary.
In this post we show you how phosphorus excesses and deficiencies affect to cannabis plants. We explain you how to act in case of over-fertilisation
Sources of phosphorus:
An excess of Fe and Zn may cause the symptoms of a phosphorus deficiency by preventing the plant from being able to absorb phosphorus properly. If you believe there may be a buildup of nutrient salts in your growing medium (or if you are growing in hydro and have not recently flushed or changed your reservoir) you should make sure it’s not an excess of other nutrients that is actually causing the phosphorus deficiency to appear. Flush your plant thoroughly with properly pH’ed water containing a regular dose of cannabis nutrients including phosphorus, or completely change your reservoir if you believe that an excess of nutrient salts may be causing the phosphorus deficiency.
When you notice that stems are turning red or purple starting from underneath, it may be a sign of a phosphorus deficiency only if accompanied by other symptoms. If the only symptom shown by your plant is red or purple stems, and you are not seeing any other signs of splotches or unhealthy leaves, the red or purple stems are likely caused by the genetics of your plant. If that’s the case, you have nothing to worry about.
Cooler temperatures lower than 60°F (15°C), as well as large temperature swings, can make it harder for the plant to absorb phosphorus. Cannabis plants are therefore more likely to show signs of a phosphorus deficiency when the temperature drops too low, or if they go through a cold spell.
It’s important to remember that some cannabis strains naturally grow with red or purple stems even when all their nutrient needs are being fulfilled, so red or purple stems is not a symptom to worry about on its own.
The progression of a cannabis phosphorus deficiency
A common symptom of a cannabis phosphorus deficiency is bright red or purple stems, though it doesn’t appear on all affected plants. Red stems can also be caused by direct light exposure (like a “tan”)
If you suspect your growing cannabis plant has a phosphorus deficiency, flush your system with clean, pH’d water that contains a regular dose of cannabis-friendly nutrients that includes phosphorus. This will remove any nutrient salts that may be affected the uptake of phosphorus and help restore pH to the proper levels.
When there is a phosphorus deficiency, the lower (oldest) leaves turn dark green. Leaves occasionally get a bluish or bronze tinge, and may thicken or curl downward before exhibiting dark gray, bronze or purplish splotches. Sometimes the stems of the affected leaves will turn bright red or purplish, usually starting from underneath.
Phosphorus deficiencies cause dark splotches on leaves and can appear at the bottom of the plant on some of the oldest leaves. Learn to spot & fix the issue.