Like all living things, cannabis requires food to survive. Along with other supplementary nutrients, nitrogen, potassium, and phosphorus are three primary components. If untreated, a phosphorus deficiency in weed can be fatal.

Cannabis plants that have not received enough phosphorus can become unhealthy, whether the grower is a beginner or an expert. We will discuss how to recognise the problem, its causes, its symptoms, how to resolve it, and what a phosphorus burn is. Let’s get going!

Phosphorus deficiency: What is it?

Weed plants suffer from phosphorus deficiencies when their roots don’t take in enough nutrients. The plant gradually runs out of the excess supply and exhibits degeneration.

Cannabis plants that lack phosphorus usually exhibit stiff leaves, discoloured leaves, red or purple stems, or abnormal growth.

There are numerous causes for weed plants to lack phosphorus. There is an excess of zinc or iron, the pH becomes unbalanced, or your grow room is too cold.

What benefits does phosphorus give plants?

What makes phosphorous so important? For all varieties of marijuana plants, it is a crucial nutrient.

Phosphorus is essential for the growth of cannabis plants’ DNA and RNA, which use the genetic code to build proteins and produce a high-yielding crop. Weed plants that lack phosphorus are unable to harvest marijuana.

This nute supports the growth and sturdiness of the roots and stems during the vegetative stage. Cannabis plants that lack phosphorus develop weak roots incapable of taking up nutrients.

Phosphorus aids in the growth of big leaves, flowers, and potent buds in the marijuana plant’s flowering period. Your harvest won’t be robust or high-yielding without the nutrient.

What causes weed plants to lack phosphorus?

Phosphorus does not take a holiday now and again. You have a phosphate deficiency in your cannabis plants for a reason.

A few things may cause the problem. Let’s examine some potential causes.

Unbalanced pH

For any growing environment, a pH metre is an essential piece of equipment. You want the range to be somewhat acidic, between 5.5 and 6.5. The pH range enables appropriate nutrition and water absorption by cannabis roots.

Weed plants may become phosphorus deficient when the pH is wrong. You should monitor the pH levels of your cannabis plants as soon as you see any symptoms.

The water or nutrients you’re using can have an impact on pH. If you use tap water, additional minerals or elements might affect the levels. When nutrients are overly concentrated, the growing medium may become excessively acidic.

Before adding your water and nutrient mixture to your growing medium, test the mix’s pH. Doing this can prevent your weed plants from lacking phosphorus.

Extra iron and zinc

An abundance of another element frequently causes a nutrient deficiency. There is often too much iron or zinc in cannabis plants when there is a phosphorus deficiency.

A surplus of iron causes bronze or brown specks on leaves, which causes the blades to wither. As a weed grower, you must regularly inspect your plants’ stems and foliage for symptoms.

Cooler temperatures in the grow room

Firstly, depending on their growth stage, marijuana plants prefer a warm environment between 20°C and 24°C. Your weed plants are more likely to have a phosphorus deficiency when the temperature falls below 20°C.

Because the roots are too cold to absorb additional nutrients, the marijuana plant grows stunted and eventually dies.

Keep the temperature constant throughout the grow room by keeping a thermometer. Sometimes, a room’s lower walls or an area near a window are noticeably cooler than other areas. Cannabis may become phosphorus-deficient as a result of this chill.

Symptoms of a phosphorus deficiency in cannabis

You might be wondering what the signs of a marijuana phosphorus deficiency are now that you are aware of the causes.

There are some critical signs of a phosphorus deficiency in weed plants, even though many nutrient deficiencies present similarly. For example:

• Discolouration of leaves
• Dry or stiff leaves
• Red or purple stems
• Stunted growth

How to Treat Cannabis Plant Phosphorus Deficiency

How do you correct your cannabis plants’ phosphorus deficiency now that you know they likely have one? We have the answers.

Let’s examine the best methods for treating a phosphorus deficiency in marijuana.

Flush out your marijuana plant.

Flushing out your marijuana plant is the first thing you should do if you have a cannabis phosphorus deficiency. Make sure the drainage is adequate. It would be best if you used distilled or purified water for this.

Run water through the growing medium for a few minutes to flush the nutrients.

Restore nutrients with fertiliser

Once your growing material is flushed and free of a marijuana phosphorus deficiency, you need to add a balanced fertiliser. 

For best results, use a fertiliser meant for cannabis to prevent a future phosphorus deficiency in your weed plants. These nutes have the correct blend of nitrogen, potassium, phosphorus, and other essential elements. 

Restore pH levels

Firstly, you must increase the pH level if that is the source of your issue. Make sure to restore the phosphorus level to a range of 5.5 to 6.5 to prevent a phosphorus deficiency in your weed plants.

Before putting the nutrients in the growing medium, test them. Add more pure water to the mixture if it is too acidic to balance.

Increase the grow room temperature

For the roots to properly absorb nutrients and avoid a phosphorus deficiency in your cannabis plants, your grow room shouldn’t be any colder than 20°C.

See if there are any window cracks or if your air ventilation system needs to be repaired if heat is escaping from your grow room. You must address these issues to avoid future problems.

To help prevent a future phosphorus deficiency in your weed plants, you might need to buy central heating or a space heater if you live in a colder climate where the nights regularly drop below 20°C.

What does cannabis plant phosphorus burn mean?

Cannabis plants experience a phosphorus burn when there is an excess of nutrients in the growing medium. It is the exact opposite of a weed deficiency in phosphorus.

When phosphorus is burned in cannabis, other vital nutrients like zinc, iron, magnesium, copper, and calcium are entirely locked out. Zinc is usually the first element to be locked out.

For example, these signs of phosphorus burn in cannabis plants can be used to diagnose it:

• The upper leaves have yellow veins.
• The leaf tips appear burned.
• Young leaves have thin fingers.
• The bottom leaves are spotty and curled.

Final points on weed lacking in phosphorus

In summary, phosphorus is one of the three essential nutrients for cannabis plants. Phosphorus deficiency in weed plants should be taken seriously because it can be fatal. An excess of other elements, a pH imbalance, or cold temperatures can all contribute to a deficiency.

Examine your plants now that you are fully informed regarding the phosphorus deficiency in marijuana. Buy high-quality marijuana seeds from Mediseed Man now if you haven’t already!