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Cannabis nutrients guide: Grow healthy, high-yield plants
Nutrients can make or break your cannabis grow
Get it wrong, and you’ll end up with weak plants, small buds, or worse, no harvest at all.
If you’re struggling to get the healthy, high-yield plants you’re after, this guide has the answers you need.
Neglecting your plant’s nutrient needs or using the wrong types can lead to deficiencies, nutrient burn, or poor growth, wasting time, effort, and money.
In this post, you’ll learn about essential cannabis nutrients, the best options for soil, coco and hydroponics, and how to avoid common mistakes like nutrient lockout.
Disclaimer: Any information given on this site is for educational purposes only. Please ensure if you’re growing cannabis, you’re doing so by the law and subject to appropriate permissions and licenses of the applicable country.
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What nutrients do cannabis plants need?
Cannabis plants need three primary macronutrients - Nitrogen (N), Phosphorus (P), and Potassium (K) - known as the NPK ratio.
Nitrogen (N)
Essential for vegetative growth. It helps produce chlorophyll for photosynthesis and promotes leafy, robust growth.
Phosphorus (P)
Critical for strong root development and flower production. It’s especially important during the flowering stage.
Potassium (K)
Supports overall plant health, helping regulate water and nutrient uptake while boosting resistance to stress.
In addition to NPK, cannabis plants require other nutrients:
- Secondary nutrients: Calcium, Magnesium, and Sulphur.
- Micronutrients: Zinc, Iron, Copper, and Boron.
Balanced nutrients at every stage of growth, from seedlings to flowering plants, are key to healthy development.
Choosing between organic and synthetic cannabis nutrients
When selecting the best nutrients for cannabis plants, you’ll come across two main options:
- Organic nutrients for cannabis.
- Synthetic (salt-based) nutrients.
Both offer unique benefits, but they also have drawbacks.
The best choice ultimately depends on your growing style, budget, and goals.
Organic nutrients
Organic cannabis nutrients are derived from organic ingredients and natural sources such as fish blood, bone meal, bat guano, earthworm castings, or homemade compost teas.
They work by slowly releasing essential nutrients while supporting the soil’s ecosystem.
Pros of organic nutrients:
- Many cannabis cultivators claim they produce better taste and aroma in the final product, thanks to the presence of natural compounds.
- They promote beneficial microorganisms, which improve soil health and the uptake of nutrients.
- They’re ideal for growers using organic soil amendments or striving for entirely natural, veganic methods.
Cons of organic nutrients:
- They can be messy to work with and often have a shorter shelf life.
- Organic options can be expensive, especially when sourced from quality materials.
- Certain types, like veganic nutrients (made from rotting plant matter), are time-consuming, hard to balance, and can produce strong odours.
- Liquid organic solutions can smell unpleasant and lack the precision of salt-based alternatives.
Synthetic nutrients
Synthetic cannabis nutrients, often referred to as salt-based nutrients, are specifically engineered for precise and efficient feeding.
These cannabis growing nutrients are formulated to deliver the ideal NPK ratio and are highly soluble, ensuring fast absorption.
Pros of synthetic nutrients:
- They are cost-effective, highly concentrated, and deliver excellent results with smaller amounts.
- Synthetic nutrients have a longer shelf life compared to organic options, making them easier to store.
- They are less messy, odour-free, and more convenient for indoors or hydroponics.
Cons of synthetic nutrients:
- Some growers argue that synthetic nutrients can affect the final product’s flavour and aroma, although this is widely debated.
- Overfeeding can easily lead to nutrient burn or lockout if you’re not careful.
Liquid vs. powdered nutrients
When choosing between liquid or powdered options, consider your budget, grow setup, and level of experience.
Liquid nutrients
These are premixed, ready to use, and easier to mix, making them ideal for beginners.
However, they are diluted, bulky, and expensive to transport, as you’re essentially paying for water.
Powdered nutrients
These are more cost-effective, concentrated, and have a longer shelf life.
A small amount goes a long way, offering more value for your money.
However, you’ll need to measure carefully when you prepare cannabis nutrients.
Cannabis nutrients for different growth stages
To achieve healthy, high-yield cannabis plants, you must match your feeding strategy to the plant’s life cycle.
Nutrient needs change as your cannabis grows from seedlings to full-flowering plants, and understanding these stages will help you provide the correct nutrients at the right time.
Seedling stage
The seedling stage is all about careful management.
At this stage, cannabis seedlings are delicate and have minimal nutrient requirements.
- Start with a mild nutrient solution or diluted organic teas. If you’re growing in rich soil, seedlings can often survive on the nutrients already present in the soil.
- Overfeeding is a major risk. Applying too many nutrients early on can cause nutrient burn, manifesting as scorched leaf tips and stunted growth.
- Use a light NPK ratio (e.g., 1-1-1) to gently support root development and initial growth.
Tip: In hydroponics or coco coir, start with very low-strength nutrients (about 25% of the recommended dosage) to avoid shocking your seedlings and poor seed development.
Vegetative stage
Once your cannabis plants enter the vegetative stage, their growth rate explodes.
This phase focuses on vigorous growth, so your plants will demand high levels of nitrogen (N).
Nitrogen is crucial for producing chlorophyll, promoting leafy growth, and building strong branches capable of supporting future buds.
- Look for cannabis nutrients with an NPK ratio high in nitrogen, such as 3-1-2 or similar.
- Incorporate amino acids or microorganisms to improve nutrient usage, boost the health of your plants, and strengthen the root zone.
- Monitor your pH levels regularly to ensure proper nutrient absorption. Aim for a pH of around 6.0 - 6.5 in soil or 5.8 - 6.2 in hydroponics.
A consistent feed schedule during this phase is critical. Adjust the frequency and strength of feeding based on your growing medium:
- Soil growers: Feed every 1–2 waterings.
- Hydroponics/coco: Feed daily with a properly balanced solution.
Tip: Avoid adding too much nitrogen, as excessive levels can cause nitrogen toxicity, leading to dark, drooping leaves and nutrient imbalances.
Flowering stage
As your plants transition into the flowering stage, their nutrient demands shift dramatically.
The focus now moves away from leafy growth to bud production.
- Reduce nitrogen and increase phosphorus (P) and potassium (K), which are essential for:some text
- Developing large, dense flowers.
- Strengthening the plant’s roots to absorb more nutrients.
- Look for cannabis flowering nutrients with a higher P-K ratio (e.g., 1-3-3 or 0-5-4).
Stages of flowering and feeding adjustments
Early flowering (Weeks 1–3):
- Gradually reduce nitrogen and introduce flowering nutrients.
- Switch to a bloom fertilliser.
Mid-flowering (Weeks 4–6):
- Focus on high levels of phosphorus and potassium.
- Ensure consistent watering to avoid lockout or buildup in the root zone.
Late flowering (Weeks 7–9):
- Gradually taper off nutrients and reduce nitrogen to improve bud flavour.
Supplements and additives during flowering
While the basics, base nutrients with a flowering-specific NPK ratio, are essential, some growers use supplements to maximise results:
- Bloom boosters: Enhance flower production with extra phosphorus and potassium.
- Sugars/carbohydrates: Boost energy levels in plants, supporting resin and bud development.
Warning: Overloading supplements can burn your plants or affect the flavour of your final product. Simplicity often works best.
By aligning your feeding strategy with each growth stage, you’ll set your plants up for healthy development and abundant yields.
Nutrients for different growing methods
The cannabis nutrients you use will depend heavily on your chosen growing medium.
Whether you grow in soil, a hydroponic setup, or coco coir, each method has specific requirements for feeding your plants effectively.
Understanding these needs ensures your cannabis receives the right balance of nutrients without risking nutrient deficiencies, nutrient lockout, or poor growth.
Growing in soil
Soil remains the most traditional and beginner-friendly medium for cannabis cultivation.
It naturally contains some nutrients, providing your plants with essential macronutrients and secondary nutrients to get started.
However, most soils require supplementation for optimal growth and robust yields.
- Soil growers often prefer slow-release options like soil amendments or homemade compost teas. These solutions feed both your plants and the microorganisms in the soil, enhancing the overall health of your plants.
- Popular organic materials include worm castings, bat guano, and bone meal, which gradually release essential nutrients.
- Growers can use premixed, synthetic liquid or powdered solutions of cannabis nutrients for soil to supplement nutrient levels and ensure a balanced NPK ratio.
Tip: Monitor pH levels (6.0 - 6.5) closely to prevent nutrients from being locked out and optimise their uptake.
Hydroponics
In hydroponics cannabis cultivation, plants grow without soil and rely entirely on water-based nutrients.
This setup requires you to precisely feed hydroponic nutrients for cannabis because your plants have no access to nutrients otherwise.
- Choose the best hydro nutrients for cannabis with a balanced NPK ratio. These are usually salt-based nutrients that dissolve quickly and deliver precise feeding.
- Check and adjust pH regularly (5.8 - 6.2) to avoid pH imbalances and lockout and ensure maximum absorption.
- Avoid nutrient buildup in the root zone by maintaining a proper feed schedule and flushing your system periodically.
Hydroponics is ideal for growers looking for control and precision but requires careful monitoring to avoid imbalances.
Coco coir
Coco coir is a versatile, soilless medium that combines aspects of soil and hydroponics.
It retains moisture well while providing hydroponic-like control.
- Coco coir is inert, meaning it contains no natural nutrients. You’ll need to feed your plants with a balanced solution of nutrients tailored for coco coir to avoid nutrient deficiencies.
- Choose cannabis grower-friendly nutrients specifically designed for coco coir’s unique properties, often with added calcium and magnesium to compensate for nutrient retention.
- Monitor pH (5.8 - 6.2) regularly to ensure proper absorption and prevent lockout.
Tip: Coco works well with salt-based nutrients and delivers results similar to hydroponic systems but with added forgiveness for beginner growers.
By understanding the needs of your medium, soil, hydroponics, or coco coir, you can choose the proper cannabis nutrients and maintain a balanced feeding plan.
Each method has advantages, and selecting the best nutrients for your setup will ensure healthy cannabis growth and impressive yields.
Avoiding nutrient problems with your cannabis plants
Even the most experienced cannabis growers face nutrient issues from time to time.
Problems like deficiencies, nutrient burn, and nutrient lockout can hinder cannabis growth, reduce yields, and leave you frustrated.
However, identifying these problems early and knowing how to fix them will ensure your plants stay healthy throughout their life.
Nutrient deficiencies
Nutrient deficiencies occur when your plants don’t receive enough of one or more essential nutrients.
This can happen due to an imbalanced nutrient solution or incorrect pH.
Signs:
- Nitrogen deficiency: Yellowing lower leaves in the lower half of the plant, stunted vegetative growth, and weak stems.
- Phosphorus deficiency: Dark green or purplish leaves, poor root system development, and slow or delayed flowering.
- Potassium deficiency: Yellowing leaf edges, brown spots, and poor stress resistance.
Other signs include slow growth, poor bud development, and weak-looking plants.
Solution:
- Identify which nutrients are lacking (e.g., nitrogen, phosphorus, potassium) and adjust your feed schedule.
- Use a balanced nutrient mix that meets the nutrient requirements for your plant’s stage of growth.
- Check pH to ensure your plants can absorb all the nutrients they need.
Nutrient burn
This happens when you feed your plants too much or your dry back is too extreme, overwhelming their ability to absorb nutrients.
This is common when using synthetic nutrients or when feeding is not adjusted for the plant’s growth stage.
Signs:
- Brown or scorched leaf tips (often referred to as “burnt tips”).
- Curled, crispy edges on leaves.
- Overall, poor uptake of nutrients leading to slow growth.
Solution:
- Flush your soil medium with plain water to remove excess salts or a buildup of nutrients at the root zone. If you grow hydroponically, use a half strength solution to flush buildup.
- Reduce feeding strength and follow a proper cannabis nutrient schedule. Start slow and increase gradually based on plant response.
Nutrient lockout
This occurs when improper pH or excess salts in the root zone prevent your plants from absorbing available nutrients.
Your plants can have all the nutrients they need, but they can’t take them up due to this imbalance.
Causes:
- pH levels are out of range (too high or too low).
- Overfeeding causes salt buildup, which blocks nutrient absorption.
Signs:
- Deficiency-like symptoms: Yellowing leaves, stunted growth, or poor flowering.
- Sudden decline in overall plant health, even with regular feeding.
Solution:
- Check and correct the pH in your soil or hydroponic setup. Aim for:some text
- Soil: 6.0 - 6.5
- Hydroponics/Coco Coir: 5.8 - 6.2
- Flush your growing medium with pH-balanced water to clear excess salts and restore proper nutrient uptake.
Tips for avoiding nutrient problems
- Use high-quality nutrients tailored for cannabis plants to avoid imbalances.
- Monitor your plant’s health regularly and adjust your solution of nutrients as needed.
- Follow a consistent schedule for feeding that’s appropriate for the plant’s stages of growth.
- Check and maintain the correct pH to ensure proper uptake of nutrients.
- Avoid overfeeding - more isn’t always better, and excess nutrients can burn your plants or cause lockout.
A note on overfeeding:
If you don’t want to burn your plants, it’s essentil that you measure your EC.
EC pens are cheap and easy to use and accurate.
You mix the nutrients, regularly check with your pen and you’re good to go.
Cannabis likes a range of ECs, depending on your level of experience and growing style.
A good rule of thumb is to stick with an EC below 1.8. But some growers push their EC to 3.5 even 4.
As a beginner, the main takeaway is, the less regularly you feed, the larger the dry back in between waterings.
This means the higher the EC spike in the substrate which means you’ll need to feed at a lower EC.
The reverse is true if you're watering very regularly with coco, you can get away with a higher EC becasue the drybacks are a lot less.
By monitoring your plants closely and maintaining balanced nutrient ratios, you can easily avoid these common pitfalls.
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Simple nutrient plan for success
You don’t need to overcomplicate feeding. A few high-quality base nutrients can go a long way.
- Start with balanced nutrients specific to cannabis plants.
- Follow a simple feed schedule for each growth stage.
- Avoid spending on unnecessary supplements until you master your environment.
Focusing on consistent feeding and maintaining your growing environment (light, airflow, and humidity) will often deliver better results than adding more nutrients.
Organic vs. salt-based?
Many growers debate whether organic or salt-based nutrients produce the best cannabis.
- The best organic nutrients for cannabis are often linked to improved flavour and aroma, thanks to natural compounds and microorganisms.
- Salt-based nutrients, however, are precisely engineered to maximise yields and are cost-effective.
At the end of the day, the “best nutrients” depend on your preferences, budget, and growing style.
Supplements: Are they worth it?
Nutrient manufacturers offer countless supplements promising to enhance specific aspects of cannabis growth.
These products are designed to target particular needs, often for growers looking to fine-tune their results:
- Amino acids: Support root and shoot development, improving overall plant strength and resilience during the vegetative stage.
- Bloom boosters: Provide extra phosphorus and potassium to increase the production of flowers and improve bud density during the flowering stage.
While these supplements can offer benefits when used correctly, they’re not essential for growing great cannabis.
Many growers achieve excellent results with just a few high-quality base nutrients and a well-managed feed schedule.
Overloading your plants with unnecessary supplements adds complexity, increases costs, and can lead to issues like a buildup of nutrients or nutrient burn.
Keep it straightforward: Focus on providing balanced essential nutrients, maintaining proper pH, and ensuring a healthy growing environment.
Cannabis plants thrive when their basic needs are met, so start simple and avoid overcomplicating your grow.
Final tips for cannabis growers
1. Always choose nutrients specifically designed for cannabis.
Generic fertilisers may lack the proper nutrient ratios for optimal growth and yields.
2. Adjust your nutrient solution as your plants move through their life.
Match nutrients to each growth stage: seedling, vegetative, and flowering for the best results.
3. Monitor your pH regularly to avoid lockout.
Proper pH ensures your plants can absorb nutrients efficiently, preventing deficiencies.
4. Start simple: Don’t overwhelm yourself with multiple supplements.
A few quality base nutrients are enough to grow excellent cannabis.
5. Observe your plants daily for signs of nutrient issues.
Look for early symptoms of nutrient deficiencies, nutrient toxicity, or imbalances, like yellowing leaves or brown tips.
Catching problems early helps you adjust your feed schedule or pH before they affect your plants negatively.
Takeaways
In cannabis cultivation, feeding your plants the proper nutrients is the foundation of growing healthy, high-yield cannabis.
Every successful growing cycle starts with understanding what your plants need and when they need it.
Choosing the correct nutrients, whether organic or synthetic, can make all the difference in achieving intense, vigorous growth and maximising your harvest.
Organic nutrients offer a natural approach, often enhancing the taste and aroma of your final product while supporting microorganisms in the soil. However, they can be messy, expensive, and slower to release nutrients.
On the other hand, synthetic nutrients provide precision and affordability, delivering fast, targeted feeding, which is ideal for growers looking to maximise control over their results.
The key to success lies in balance and consistency.
Stick to a simple nutrient plan that aligns with your plant’s cycle - feed lightly in the seedling stage, increase during vegetative growth, and adjust for the flowering stage.
Monitor your plants closely for any signs of nutrient deficiencies or nutrient burn, and always keep an eye on your pH to avoid issues like nutrient lockout.
Combine a smart feeding strategy with a stable growing environment - proper lighting, airflow, and temperature, and you’ll set your plants up for success.
With the right approach, you’ll achieve strong growth, healthier plants, and a harvest to be proud of.
Happy growing!
FAQs
What nutrients should I feed cannabis?
To grow healthy, high-yield cannabis, you need to provide the correct nutrients at each stage of growth.
Cannabis plants require three nutrients most: nitrogen (N), phosphorus (P), and potassium (K), which is known as the NPK ratio.
- Seedlings: Use mild nutrients for cannabis seedlings or light organic teas. Avoid overfeeding to prevent nutrient burn.
- Vegetative stage: Focus on high nitrogen levels to encourage strong growth and leafy development. Supplement with secondary nutrients like calcium and magnesium for strong stems and roots.
- Flowering stage: Reduce nitrogen and increase phosphorus and potassium for improved flowering and bud development. Look for best nutrients for flowering cannabis, such as bloom boosters with a higher P-K ratio.
Choose between organic nutrients (like compost teas or amendments) or synthetic nutrients for precision feeding.
Powdered nutrients are more cost-effective, while liquid options are easier to mix.
If growing hydroponically, use hydro nutrients tailored to your setup.
For coco coir, add extra calcium and magnesium to prevent nutrient deficiencies.
Finally, always monitor your plant’s pH to ensure proper nutrient uptake and avoid lockout.
Matching the right nutrient ratios to your plant’s needs will keep your cannabis plants thriving at every stage.
Can you give cannabis too much nutrients?
Yes, you can absolutely give cannabis plants too many nutrients, and it can cause more harm than good.
Overfeeding leads to nutrient burn, one of the most common problems growers face.
This occurs when your plants receive excessive essential nutrients, particularly in synthetic or concentrated feeds, which overwhelms the root zone.
Signs of nutrient burn:
- Brown or scorched leaf tips.
- Curled, crispy edges.
- Slow growth and poor overall plant vigour and health.
Excess nutrients can also result in nutrient buildup, especially in hydroponics or coco, which causes lockout.
This means your plants can’t absorb the nutrients they need, leading to deficiencies despite overfeeding.
To prevent overfeeding:
- Start with a low-strength solution and increase gradually.
- Follow a proper feed schedule tailored to the plant’s stages of growth.
- Monitor pH levels and flush your growing medium periodically to clear excess salts.
More nutrients do not equal better growth. Cannabis thrives when provided with the correct nutrients in balanced ratios.
By keeping it simple and avoiding overfeeding, you’ll prevent issues and ensure your plants remain healthy, strong, and high-yielding.
How many times a week should I feed my cannabis?
How often you feed your cannabis depends on the growing medium, plant stage, and nutrient choice, but consistency is key to healthy growth.
- Soil: For soil-grown plants, feed 1- 2 times per week, alternating with plain water. High-quality organic nutrients or slow-release amendments can reduce the need for frequent feeding. Overfeeding can cause nutrient buildup and nutrient lockout, so always monitor your plants closely.
- Hydroponic systems: In hydroponics, plants rely entirely on a nutrient solution. Feed daily with balanced hydro nutrients while regularly checking pH and adjusting to avoid imbalances. Flushing the root zone periodically prevents salt buildup.
- Coco coir: Feed 3–5 times a week in coco coir, as this medium retains moisture but lacks natural cannabis soil nutrients. Use coco-specific nutrients with added calcium and magnesium to prevent nutrient deficiencies.
For all methods, follow a proper feeding schedule tailored to the plant’s life cycle - less for seedlings, more during vegetative growth, and targeted nutrients during the flowering stage.
Always observe your plants: yellowing leaves or burnt tips are signs to adjust feeding frequency.
Feeding the right amount of cannabis nutrients keeps your plants thriving without overwhelming them.
Should I add nutrients every time I water?
No, you shouldn’t add marijuana nutrients every time you water your cannabis plants - doing so can lead to nutrient buildup, nutrient burn, or even nutrient lockout.
Whether to feed nutrients with every watering depends on your growing medium, plant stage, and nutrient choice.
- In soil: Adding nutrients every time you water can overload the medium. Soil-grown plants benefit from a balanced approach: alternate between feeding with nutrients and plain water. This allows the root zone to flush out excess salts while preventing overfeeding.
- In coco coir: Coco coir has no natural soil nutrients, so you’ll need to provide nutrients more often—typically at every watering. Include additional calcium and magnesium to prevent nutrient deficiencies.
- In hydroponics, Plants rely entirely on nutrients, so feeding with every watering is essential. Always monitor your pH and adjust to avoid pH imbalances.
Tip: Observe your plants for signs of overfeeding, such as yellowing leaves or burnt tips, and flush periodically with plain water to clear excess nutrients.
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