Fertilise cannabis properly: How often you should feed your plants - tips for every stage of growth"

Anyone who wants to grow cannabis successfully is inevitably faced with the question: How often should cannabis be fertilised? The answer depends on several factors - the growth phase of the plant, the fertiliser used for cannabis plants and the balance between nutrients such as nitrogen, phosphorus and potassium. An incorrectly chosen fertilisation scheme can lead to growth disorders, while correct fertilisation promotes vigorous plants and a high-yielding harvest.

During the growth phase (vegetation phase), cannabis plants have a high nutrient requirement, especially for nitrogen. Weekly fertilisation is recommended here. In the flowering phase, on the other hand, the plants need less nitrogen but more phosphorus and potassium. In this phase, it is sufficient to fertilise every 10 to 14 days. It is also important to stop fertilising in good time before the harvest and only rinse the plants with clear water to avoid residues.

The choice between organic and mineral fertilisers depends on your growing style. Organic fertilisers work more slowly, but are gentler on the soil. Mineral fertilisers work quickly and precisely, but require regular flushing of the substrate to prevent salt build-up.

In this blog, you will find all the important information you need to master fertilising correctly - from frequency and choice of fertiliser to the best tips for beginners. This will ensure that your plants are optimally nourished and end up with a rich harvest.

How often should you fertilise cannabis?

The frequency of fertilisation depends heavily on the growth phase of your cannabis plant. In the Wachstumsphase (also known as the vegetation phase), plants have a high nutrient requirement, especially for nitrogen, which is crucial for leaf growth. It is advisable to fertilise about once a week here, depending on which fertiliser you use. Some fertiliser manufacturers give precise dosage recommendations that you should follow.

In the Blütephase the plant's nutrient requirements change. It needs less nitrogen and more phosphorus and potassium to support the formation of large and resinous Flowers. It is often sufficient to fertilise every 10 to 14 days, but here too it depends on the exact composition of the fertiliser.

A simple rule of thumb is: Better to fertilise less, but regularly . Fertilising too frequently can quickly lead to over-fertilisation, which stresses and damages the plant. If you are using mineral fertiliser, you should also make sure to flush the soil regularly to prevent salt build-up.

It is best to keep a close eye on your plants - they will show you whether they are getting enough nutrients through their growth and the colour of their leaves. If the leaves turn yellow or discolour, this can be a sign of a nutrient deficiency or excess.

Fertilising cannabis in the different growth phases

Cannabis plants go through two main phases: the Wachstumsphase and the Blütephase . Both require different nutrients and care, which is why you should adjust your fertilisation scheme accordingly.

Growth phase: Nutrient boost for vigorous growth

In the growth phase, the focus is on building strong roots, stable stems and large leaves. Here, the plant primarily needs nitrogen, which ensures leaf growth and general vitality. In this phase, it is advisable to fertilise weekly. Use a fertiliser that is rich in nitrogen. You can adjust the amount depending on the fertiliser and substrate, but in general, it is better to use a little less to avoid over-fertilisation.

If your plants are growing healthily and have a lush green colour, you are on the right track. However, yellowing or weak leaves can indicate a lack of nutrients, while dark, burnt edges are often a sign of over-fertilisation.

Flowering phase: The right mix for strong Flowers

As soon as your plants go into Flower, their needs change. Now less nitrogen and more Phosphorus and potassium as these nutrients promote the growth of Flowers and prepare the plant for a strong harvest. In this phase, it is sufficient to fertilise every 10 to 14 days, as the plants no longer grow as quickly as in the vegetation phase.

Some growers also use special flowering fertilisers during the flowering phase, which are precisely tailored to the needs of the plant during this time. Make sure to apply the fertiliser in good time before the harvest (usually two weeks before) so that no residues remain in the Flowers.

Which fertilisers are suitable for cannabis plants?

Choosing the right fertiliser plays a crucial role when it comes to the growth and health of your cannabis plants. You can choose between two main types of fertiliser: organische and mineralische fertiliser. Both have their advantages and disadvantages, and the choice often depends on your own preferences and the desired cultivation approach.

Organic fertilisers: natural and sustainable

Organic fertilisers come from natural sources such as compost, manure or plant waste. They offer the advantage that they improve soil health in the long term and release nutrients more slowly, which reduces the risk of over-fertilisation. A popular example is Brennnesseljauche which is rich in nitrogen and can be used well in the growth phase. Another example is Wurmhumus which enriches the soil with important microorganisms and nutrients.

The disadvantage of organic fertilisers is that they take a little longer for the nutrients to be released. They are therefore ideal for growers who want to take their time and care for their plants sustainably.

Mineral fertilisers: Precise and fast-acting

Mineral fertilisers, also known as chemical fertilisers, are synthetically produced nutrients that are absorbed directly and quickly by the plants. These fertilisers are particularly helpful when your plants need a quick nutrient boost, as the nutrients are in an immediately available form. One example is the popular Biobizz fertiliser which contains many mineral components and is tailored to the special needs of cannabis plants.

The disadvantage of mineral fertilisers is that they can quickly lead to over-fertilisation if used incorrectly. In addition, salt can build up in the soil, which is harmful to plants in the long term. It is therefore important to flush the soil regularly.

Which fertiliser is the right one?

Choosing the right fertiliser depends on your goals. If you want to grow organically and in harmony with nature and are in no hurry, organic fertilisers are the best choice. However, if you want to respond precisely and quickly to the needs of your plants, mineral fertilisers are a good choice.

Organic vs. mineral fertilisers: Which is better?

One of the most frequently asked questions among cannabis growers is: Should I use organic fertilisers or mineral fertilisers? Both options have their advantages, and the decision often depends on your priorities.

Organic fertiliser: For environmentally conscious cultivation

Organic fertilisers rely on natural ingredients and promote long-term soil health. If you value sustainable, environmentally friendly cultivation, organic fertilisers are the better choice. They improve the soil structure and promote the growth of beneficial microorganisms, which in turn improve the plant's nutrient uptake. With Bio-Düngern you are less likely to risk over-fertilisation, as the nutrients are released more slowly and continuously.

An example of a proven organic fertiliser is Wurmhumus which provides your plants with a good supply of nitrogen, especially during the growth phase. Also Kompost and Brennnesseljauche are among the classics among organic fertilisers and offer your plants a gentle but effective supply.

Mineral fertilisers: precise and efficient

Mineral fertilisers consist of synthetically produced nutrients that are quickly and directly absorbed by the plants. Especially if your plants have an acute nutrient deficiency or you want to see results quickly, Mineral fertilisers on. They give you precise control over the nutrient supply and respond quickly to the needs of your plants.

A major advantage of mineral fertilisers is that they are immediately available and therefore take effect in a very short time. Especially in the Blütephase If the plant has an increased need for phosphorus and potassium, you can control this with a mineral fertiliser.

Which is better?

The decision depends on your growing style. If you want to keep your plants natural and healthy in the long term, organic fertiliser is an excellent choice. If, on the other hand, you have little time or want to see quick results, mineral fertiliser is a good choice. There are also growers who combine both methods and use organic substances with mineral fertiliser supplements to combine the best of both worlds.

Fertilising cannabis in the flowering phase

The flowering phase is the most important stage in the life cycle of your cannabis plant, as this is when it produces the much-anticipated Flowers. It is precisely in this phase that your plant needs a different nutrient composition than in the growth phase in order to develop the largest and most resinous Flowers possible. But how often should you fertilise during this time and what should you pay attention to?

Nutrients in the flowering phase

While the cannabis plant primarily needs nitrogen during the growth phase in order to develop strong leaves and roots, the nutrient requirements change considerably during the flowering phase. Now Phosphor and Kalium are particularly important as they support the formation and growth of Flowers. Phosphorus promotes the development of the flower structures, while potassium improves the quality and firmness of the Flowers.

During the flowering phase, it is often sufficient to fertilise every 10 to 14 days. You should use special Blütedünger that are precisely tailored to this phase and are low in nitrogen but high in phosphorus and potassium. Be careful not to overdo the nutrient supply - less is often more, especially in this sensitive phase.

When should you stop fertilising?

A common mistake when fertilising in the flowering phase is that many growers fertilise for too long. To get a clean and high-quality end product, you should stop fertilising about two weeks before harvest and flush the plants with clear water instead. This so-called "flushing" helps to remove excess nutrients from the substrate and the plant so that the Flowers are free of residues and taste better.

Tip: Observe the plants closely

You should also keep a close eye on your plants during the flowering phase. Yellowish leaves or sluggish flower development can indicate nutrient deficiencies, while brown tips indicate over-fertilisation. Adjust your fertiliser regimen accordingly and follow the recommendations of your fertiliser manufacturer.

Common mistakes when fertilising cannabis

When fertilising cannabis plants, it's easy to make mistakes that can affect the growth and yield of your plants. Here are some of the most common problems you should avoid at all costs.

1. over-fertilisation

One of the most common mistakes is over-fertilisation. Many growers think that "more fertiliser" automatically means "better plants", but the opposite is often the case. Too much fertiliser can burn the roots and stress the plant, which inhibits growth and, in the worst case, can destroy the plant completely. Signs of over-fertilisation are brown or burnt leaf edges and stressed plants that only grow slowly.

Tip: Always follow the manufacturer's dosage recommendations and start with a lower dosage to be on the safe side.

2. rinsing the substrate too rarely

It is particularly important to rinse the substrate regularly when using mineral fertilisers. Mineral fertilisers leave salts in the soil, which can accumulate over time and block the plant's nutrient uptake. This leads to a so-called "nutrient lockout", in which the plant can no longer absorb nutrients despite fertilisation.

Tipp: Rinse your substrate with clear water every few weeks to wash out excess salts and relieve the roots.

3. incorrect pH value

The pH value of the soil or nutrient solution is crucial for the nutrient uptake of your plant. If the pH value is not in the right range (between 6.0 and 7.0), important nutrients can be blocked, even if they are present in the substrate. Soil that is too acidic or too alkaline often leads to deficiency symptoms.

Tipp: Check the pH value of your water and soil regularly. Use pH meters or pH strips to ensure that your plants are always in the optimum range.

4. fertilising in the last two weeks

Many beginners make the mistake of continuing to fertilise until shortly before harvest. This can lead to residues of nutrients remaining in the Flowers, which can impair the flavour and even be harmful to health.

Tipp: Stop fertilising about two weeks before the planned harvest and only rinse the plants with clear water. This will ensure that no fertiliser residue remains in the Flowers.

Tips for beginners: How to fertilise your cannabis plants properly

When you're just starting out growing cannabis plants, the topic of fertilising can seem overwhelming. However, with a few basic tips, you can keep your plants healthy and avoid over-fertilising.

1. less is more

Especially as a beginner, there is a tendency to want to do too much good for the plants. But when it comes to fertilising, less is often more. Too much fertiliser can harm your plants more than help them. It's better to start with a lower dosage and increase it slowly if necessary. Observe how your plants react before adding more fertiliser.

2. stick to the fertilisation plan

Most fertiliser manufacturers provide clear instructions and fertilisation plans for their products. These plans give you good guidance on how often and in what quantity you should fertilise. It is particularly important for beginners to stick to these guidelines and not experiment. Make sure to adapt the plan to the growth and flowering phases of your plants.

3. choose the right fertiliser

It is often difficult for beginners to find the right fertiliser. Organic fertilisers tend to be easier to use as they work more slowly and the risk of over-fertilisation is lower. Mineral fertilisers work faster, but require more attention to find the right balance. If you are unsure, start with an organic fertiliser as it is easier for beginners to control.

4. do not forget to rinse regularly

Especially if you use mineral fertilisers, you should regularly rinse your plants with clear water to prevent the accumulation of nutrient salts in the substrate. This prevents nutrient blockages and ensures that your plants can continue to absorb the nutrients they need.

5. have patience

The most important tip for beginners: Be patient! Cannabis is a plant that needs time to develop. You will quickly learn how your plants react to different amounts of nutrients. Over time, you will get a feel for how often and how much fertiliser your plants really need.