Excess fertiliser and cannabis: how to detect the problem (and how to solve it)?

How to tell if you've given your cannabis too much fertilizer and how to fix it.

Modified on: 27/04/2022

Think you have given too much fertiliser to your cannabis? Find out from the plant’s symptoms if this is the case and how to repair the damage

Growing cannabis plants can bring a lot of satisfaction, but things don’t always go as planned.

From the moment that marijuana seeds are planted until the plant matures, there are often mistakes in the dosage of water, nutrients and other inputs, especially if you are not yet an expert.

Too much fertiliser for your cannabis plant can cause several problems that must be noted quickly to be corrected and remedied right away.

Suppose you are in doubt about the amount of fertiliser you should give your cannabis plants; in case you are wondering if the burning of the plants’ leaves is due to over-fertilisation and how to correct this phenomenon, here you will find all the answers you have been looking for.

Excess fertilisation in cannabis cultivation: what may it be due to?

Overfertilisation, or overfeeding your cannabis plants, is a phenomenon that is often overlooked, but it can cause considerable damage to cannabis plants.

Many believe that after planting cannabis seeds, adding numerous nutrients to the soil can accelerate growth and yield, but this is not always the case.

Excess fertilizer in hemp

This practice can lead to burns, growth disorders and even death of the plant.

And that’s not all…

In addition to the burnt leaves you will have to remove – due to too much fertiliser, you will notice after the harvest that the aroma of the over-fertilised plant is of poor quality. It can be that too much potassium in the hemp plant causes combustion with sparking and that too much nitrogen in the plants causes a scratching sensation in the throat – when the products are consumed.

However, we remind you that cultivation and consumption of cannabis are not allowed. Besides, the online weed seeds you can buy on SensorySeeds can only be purchased for collection purposes.

To avoid problems, it is essential to stick to the rules made available by the growers and adapt them to the cannabis plants concerning the phenomenon of overfeeding cannabis plants.

For example, those who have chosen to use auto flower seeds BSF, dwarf auto-flowering plants, or any other variety, should consider that each type of plant has particular needs. Like animals in the growing phase, marijuana plants should receive small amounts of nutrients. Then, the dose should be increased (cautiously) after the plant grows.

In general, it is a good idea to fertilise cannabis plants with lower doses than those indicated by the manufacturer and, if necessary, to increase the quantities later, only when the plant seems to need more nutrients.

Read also: The flowering stage for outdoor plants: the best practices!

How to detect that cannabis plants are over-fertilised?

Cannabis plants are born from two self-flowering seeds that react more or less the same way to feminized seeds when exposed to excessive doses of nutrients.

Cannabis plants generally do not have a system capable of regulating excess nutrients, but they show these signs to signal their state of discomfort:

  • Yellowing or bronzing of the leaves;
  • Folding and drying of the tips;
  • Twisting of the tips.

All these symptoms can be due to “nutrient burn”.

Cannabis plant burn can occur mainly in two phases: during the vegetative phase and the flowering.

If it happens in the first phase, it is easier to solve. But in the second phase, all the efforts made for the crop and the work done to cultivate the plant would be wasted .

What to do if you have given too much fertiliser to the cannabis plants?

As you have read, excess fertiliser in hemp can cause various damage to the plant, which can be severe or moderate.

If you wonder how you can remedy this situation, first check with a TDS meter that detects precisely how much nutrient is in a solution (PPM) to see if the problems are related to over-fertilisation. Then, examine the condition of your plants.

If the situation is not irreparable, the following precautions should be taken into account:

Plant-healthy not overfertilized.
  • Remove burnt leaves.
    If your cannabis plants have leaves that are starting to tan and are looking to turn themselves in, it is essential to remove them as soon as possible. This is because the leaves can rot after death, which encourages moulds that can cause rot near the flowers, even affecting the whole plant.
  • Plant’s washing.
    To limit the damage caused by excess fertiliser in cannabis, excess nutrients that may have settled in the roots and middle should be removed. One method is to wash with water (check for the most compatible pH). This method involves watering the plants until the water runs out of the pot and repeating the process twice in a row and twice a day. The ENEE measuring device also enables an accurate measurement of the number of nutrients that have been eliminated.
  • Check the fertilisation plan.
    Once you understand when the cannabis plants have been over-fertilised, it is essential to review your complete feeding plan. The wisest choice is to continue step by step, based on reliable data collected by the TDS meter.
  • Strengthen the roots.
    If cannabis plants are weakened by excess fertiliser, it may be helpful to use root stimulators to make them stronger and help the plant recover.

In case the cannabis plant has only suffered a minor damage from excess fertilizer, it may be enough to immediately reduce nutrient doses and water more heavily, while plant washing, which can be very stressful, should be carried out only if the plant is in a condition where recover by other means is difficult. It is true that too much water in cannabis plants is also a mistake to avoid.

Read also: When to harvest hemp buds? All useful signs for growers


As you just read, excess fertiliser in cannabis whenever the issue is not detected and corrected in time, tit can cause severe damage to cannabis farmers.

However, there are remedies, and with a bit of patience and precision, it is possible to save even the most fatigued plants.

We want to remind you that it is not allowed to grow cannabis in the UK – even for personal use – and that it is an actual crime.

Nevertheless, you can buy the best BSF cannabis seeds in our SensorySeeds shop to collect them.

We are waiting for you!