The best fertilizers, nutrients, or soil for your cannabis plants will provide important nutrients and an optimal growing environment to maximize yields. Below I list several great options for organic and non-organic grows that will help you maximize yields and keep your cannabis plants happy!

I also answer other common questions related to nutrients and cannabis growth. Happy growing!

Types of Cannabis Nutrients or Fertilizers:

• Macronutrients – Nitrogen (N), Phosphorus (P), and Potassium (K).
• Secondary Nutrients – Magnesium (Mg), Calcium (Ca), Sulfur (S).
• Micronutrients – Zinc (Zn), Manganese (Mn), Iron (Fe), Boron (B), Chlorine (Cl), Cobalt (Co), Copper (Cu), Molybdenum (Mb), Silicon (Si), Nickel (Ni), Sodium (Na), and Fluoride (F)
• Organic nutrients containing a wide range of compounds like bone meal, bat guano, worm castings, etc. These can be sold individually or come mixed into organic potting blends.
• Soil Microbes (Rhizobacteria) – added to soil to produce beneficial byproducts, often resulting in increased yields.

Which Weed Nutrient Kit Do I Recommend?

I personally recommend going with a basic three part weed nutrient kit. The kits from General Hydroponics and Fox Farm are good to consider if you only want the basics and nothing fancy. Follow the guidelines above as well as the directions on the bottle, and you’ll be fine.

If you want to consider using additional secondary nutrients like the Bud Juice Trace Micronutrients described below, feel free. But secondary nutrients are optional.

Cannabis Fertilizer – Nature’s Living Soil: Super Soil Concentrate

Super Soil Concentrate – The Easiest Marijuana Growing Medium:

Nature’s Living Soil is a fully organic living soil concentrate formulated specially for marijuana growers. Concentrate means you should mix this nutrient rich soil with regular soil. It’s also known as “soilless,” a term used to describe a soil-free growing medium.

If you feel growing cannabis is enough work already, Nature’s Living Soil may be the best option for you. It doesn’t require much work aside from initial mixing then watering until you harvest your huge marijuana plants.

The best part about living soil is you never need to add nutrients. You can re-use the living soil over and over again. It makes cannabis growing incredibly easy.

Read more about the benefits of growing with living soil

This five pound bag mixes into 25 gallons worth of super soil treated planters.

Super Soil Concentrate’s Quality Marijuana Nutrients:

Super soil marijuana fertilizer contains a long list of organic ingredients based on the recipe developed by well known marijuana cultivator SubCool. The ingredients are as follows:

Organic Earthworm Castings, High Quality Bat Guano, Blood Meal, Bone Meal, Fish Bone Meal, Alfalfa Meal, Kelp Meal, Dolomite Lime, Azomite, Epsom Salt, Coconut Water Powder, and Aloe Vera.

Super soil organic marijuana fertilizer also contains a long list of beneficial microorganisms.

The manufacturer recommends using Super Soil cannabis fertilizer within two weeks of opening the bag. If you don’t use the whole bag at once, you can store it in a cool dry place indefinitely. Re-moisten the soil before re-use and you’re ready to go.

Some users report Super Soil smells similar to manure. The smell is normal and dissipates once mixed with regular soil.

Super Soil Concentrate Marijuana Fertilizer – Directions for Use:

Nature’s Living Soil recommends not planting seedlings directly into the living soil. They recommend planting your seedlings into a small buffer zone of regular soil, and allowing the roots to grow into the mixed super soil. Water normally once done.

You do not need to add any other nutrients to your cannabis plants once you’ve potted with Nature’s Living Soil. The soil will bring your PH to a safe range, and provide all necessary nutrients for your cannabis plants.

Nature’s Living Soil Super Soil marijuana fertilizer is one of the best – and laziest fertilizers available for your use. Look no further than the stellar reviews the soil has received from cannabis growers.

Growers report being very happy, adding that their plants grow vigorously. One grower added that after they transplanted their seedlings, the increased daily growth was blatantly obvious.

Can you use regular soil to grow cannabis?

Yes, you can use regular soil to grow your cannabis, but it’s recommended to use fresh potting soil so you don’t risk any contaminants that may be present in your backyard soil.

No matter which you choose, make sure you maintain the proper pH levels so nutrients can be absorbed. Also make sure any NPK levels from the combined super soil (if it has any) plus any other added nutrients does not exceed the necessary levels.

Click Here to view Super Soil Organic Concentrate on Amazon.com

Bud Juice Organic Trace Micro Nutrients for Cannabis

Bud Juice is Organic Ocean Minerals for Your Marijuana:

Bud Juice has formulated organic cannabis nutrients meant to help your buds grow abnormally large. Bud Juice Micro Organic Nutrients for marijuana contains ocean based nutrients PLUS chelates and phytoplankton to supercharge your yield!

These minerals are derived from ocean water, but don’t worry, there’s no salt in this organic marijuana fertilizer. Approximately 95% is filtered out with the other 5% remaining present as essential chloride nutrients for your plant.

Bud Juice nutrients should not be combined with other NPK nutrients, since it already contains nitrogen, phosphorus and potassium nutrients.

Another great part about this product is it comes with easy dosing instructions for each stage of plant growth, and it only needs to be used once weekly, not with every single watering!

When you compare the price of Bud Juice to other popular brands like Bud Candy, Bud Juice is a great value considering it’s organic and has ingredients to create living soil!

Click Here To Check Out Bud Juice on Amazon

Bloom City Complete NPK 16 Week Cannabis Nutrient Kit

The folks at Bloom City know you’re stressing about growing your seedlings into tall luscious cannabis plants. Why bother with the measuring, mixing, and feeding-frequency guesswork if you don’t have to?

Bloom City developed a complete NPK veg and bloom cycle nutrient kit sufficient for bringing 4 to 8 marijuana plants through a full 16 week grow cycle. Note this is not an organic kit.

Quality Cannabis Nutrients for Any Environment:

This Bloom City marijuana nutrient kit will work in soil or soil-less mediums, indoors or outdoors. It contains high quality, organic marijuana nutrients like alfalfa meal, poultry meal, feather meal, kelp meal, crustacean meal, fish meal and ascophyllum nodosum.

This kit is not intended for purely hydroponic setups. So if you have a hydroponic setup, you may want to consider these hydroponic safe nutrients.

The Bloom City grow kit was formulated by botanists and and plant chemists in Seattle, Washington, so by following the simple steps you know your plants have good science behind them.

Bloom City Nutrient Kit Contents:

The Bloom City cannabis nutrient kit comes with easy to follow directions, and seperated nutrients for different cycles of plant growth. The kit contains one 5lb bag of 5-3-2 nutrients for the grow phase, a bottle of soil conditioner, one 5lb bag of 4-5-4 nutrients for bloom phase, instructions and a measuring cup.

This kit makes home growing easy, safe and stress free. It doesn’t come with soil, and yes, it will work for autoflowers as well!

Bloom City Cannabis Nutrients – What people are saying:

I’ve researched what people who purchased this marijuana nutrient kit are saying post-purchase. Buyers seem to be pleased with their results overall. They appreciate the simple instructions and ease of use.

The fertilizer reportedly mixes into the soil quite easily. One user reported that no additional care was needed for their plants beyond this cannabis nutrient kit, and they were very pleased with the plant yield.

If you don’t want to worry about whether you’re overfeeding or underfeeding, and like having all the steps laid out for you, then this kit is definitely for you.

Mammoth P Soil Microbes – Scientifically Proven Increased Cannabis Yields By 16%

Mammoth P is professionally developed soil microbes. These microbes, also known as rhizobacteria, act as a beneficial addition to your plant’s ecosystem. Certain genus of bacteria have been found to increase yield and accelerate time to flowering in certain crops.

If you’re not growing your cannabis outdoors or even in a specific outdoor geographic region, you’ll be missing out on these beneficial microbes that exist naturally in those environments. Mammoth P is the answer to that.

Mammoth P was tested specifically on cannabis, and proven to increase yields by 16% over industry-standard fertilizers.¹ This means Mammoth P is one of the best cannabis nutrients on the market.

It has several other benefits to your cannabis plant as well. The first is that the microbes produce nutrients in the soil that benefit bud production. Second is the increased phosporus levels that help keep your plants’ internodes short.

Plants treated with Mammoth P in the study cited at the end of this review grew 8.9% taller on average.

In addition, other studies have found that endophytes (bacteria or fungus living on plants) have demonstrated protective activity against pathogens dangerous to cannabis plants (and other plants), and even the much dreaded white powdery mildew.²

Watch my video on the benefit of soil microbes like Mammoth P:

Less Expensive Alternative:

Mammoth P is pretty expensive. Fortunately there are other tried and true alternatives that cost a fraction of the price. One very popular soil microbe brand for cannabis growers is…

Real Growers Recharge

Although it’s a different blend of microbes than Mammoth P, growers are getting incredible results and word of mouth has spread quickly among the home growing community. You can find out more details about Real Growers Recharge by clicking here.

If you go with any type of soil microbes, you should consider supercharging them with Unsulphured Blackstrap Molasses (read my article here). The microbes eat the sugary molasses and create CO2 as a byproduct, which supercharges your plant growth.

How long will a 500ml Mammoth P bottle last?

Mammoth P suggests 1-4ml per gallon of water. Assuming you use between 2 and 4ml per gallon, a 500ml bottle will make you 125-250 gallons of water.

Tips for use:

• Mammoth P reduces the need for a separate enzyme additive. That said, growers have used this safely with other supplements and in cloners.
• It’s safe to use in soil, super soil, and soilless applications.
• Try to finish Mammoth P within 6 months of opening. Unopened these will stay fresh for at least 2 years.
• The microbes are designed to bounce back from a frozen state, so no need to worry if you’re shipping these through a cold climate.
• What if Amazon runs out of stock? LED Grow Lights Depot also carries Mammoth P if Amazon runs out.

Click Here To Check Out Mammoth P Soil Microbes On Amazon

Video:

What’s the proper NPK level for Cannabis Nutrients?

Believe it or not, there is no exact ratio of N-P-K that’s perfect for cannabis growing. If you’re looking for a good NPK ratio starting point, 7-4-6 would be good for the vegetative phase and 2-9-9 for flowering.

It’s generally understood that cannabis plants need more Nitrogen, less Potassium and Phosphorous during the vegetative phase, and less Nitrogen/more Potassium and Phosphorous during the flowering phase.

Cannabis growers tend to follow those guidelines, and sometimes experiment with their own individual ratios of N-P-K.

Most nutrients are designed to benefit one stage of plant growth over the other due to the fact that each growth phase demands different ratios of nutrients.

For example, vegetative phase focused NPK products are high in nitrogen needed for vegetative stage growth, while Flowering focused NPK products have a high phosphorus content for flower development.

Not all of the fertilizers mentioned below are NPK fertilizers. You can use organic cannabis nutrients and soil microbes in addition to the NPK fertilizers or use them alone.

Do Cannabis Seedlings Require Nutrients?

No, cannabis seedlings do not require nutrients during the seedling stage, which is the first 2-3 weeks of growth, or until you have 2-3 fully formed leaves showing.

Giving nutrients to your seedlings will do more harm than good. Focus on the proper amount of light and water to walk your seedlings through to the vegetative phase of growth.

If you insist on giving your cannabis seedlings nutrients, you may try a water diluted 1/5 dose of vegetative phase nutrients.

How Much Nutrients Do I Feed Cannabis Plants?

Nutrient products generally recommend too high of a dose for cannabis plants. This could be because they want you to use as much as possible, or it could be that the nutrient dose was calculated for a different type of plant.

A safe approach to finding the right cannabis nutrient dosage is to start with 1/3 or 1/2 of the dose recommended on the nutrient bottle. If you feel think the plant appears to need more, you can slightly increase the dose.

The phrase “less is more” really holds true with nutrients.

Should You Use Nutrients Every Time You Water Cannabis Plants?

You don’t need to use nutrients every time you water cannabis plants. You can feed nutrients to your cannabis plants every other time you give them water. People have indeed fed their plants nutrients with every watering and the harvest turned out fine. But your cannabis plants likely won’t utilize all the nutrients if you do feed them with every watering.

One great tip for deciding if and when you should give your plants more or less nutrients is to pay close attention to the way your plants look each day. If you notice the leaves are a bit too lime green looking, the plants may need more nitrogen. But if the leaves are too dark and shiny, the plant probably needs less nitrogen.

If the plant looks normal, you’re probably on the right track. Being able to tell what’s normal and what’s not comes with having some growing experience. You can use those observation skills to guide you through your grow as needed.

Where Does Cal-Mag (Calcium & Magnesium) Come Into The Picture For Growing Cannabis Plants?

Cal-Mag, short for calcium and magnesium, is a secondary nutrient mix you may end up needing while growing your cannabis plants. Knowing when and if your plants need cal-mag can be a little tricky.

It can be tricky because concentrations of calcium and magnesium vary in tap water from different regions, as well as in different grow mediums. So some people’s plants may need it and others may not.

Living soil can have good levels of cal-mag from lime and epsom salt, among other items. But even that doesn’t mean living soil won’t become depleted before your grow is finished.

The best way to determine if your plants need cal-mag is by looking for the obvious rust spots on your leaves. Take a look at the image below.

Another use for cal-mag when growing cannabis is to increase the PPM of your water once you’ve run your water through a reverse osmosis filter. While reverse osmosis filtration removes contaminants from your water, it leaves the PPM too low for watering, so calmag is perfect for bringing the PPM back into normal range.

Signs Your Cannabis Plant Needs Cal-Mag:

Signs of needing cal-mag can include rust spots on the middle of the leaves, as well as similarly colored leaf edges. Lower leaves may be curled or sick looking. There may be yellowing between the veins on the leaves. The flowering process can be taking a longer time than normal.

Add 5ml of calmag per gallon of water and feed. Once the problem resolves you can decrease calmag to 1ml per gallon, or stop altogether.

Feed Too Much Cannabis Nutrients? How to Fix it:

There’s a symptom called nutrient burn where your cannabis leaves turn yellow or look “burnt” a considerable amount of time prior to harvest. This is due to overfeeding with marijuana nutrients.

How to Fix Cannabis Nutrient Burn:

Although the leaves may not recover, you can fix cannabis nutrient burn and save your plant by flushing your soil with a regular amount of plain water.

Nitrogen toxicity causes leaves to turn dark green and shiny. If your leaves look like that – lighten up on the nitrogen!

Yellowing leaves near the plant’s base prior to harvest is normal, so it’s important to distinguish if yellow cannabis leaves are natural or not. You should know based on how much nutrients you’ve been feeding.

If you’re unsure, using a little bit less nutrients is better than risking your plant. If you’ve accidentally overfed one of your marijuana plants, you can flush them with pH neutral water, but don’t flush them the week before flowering.

If you feel uncomfortable measuring out nutrients on your own, it’s best to purchase a predefined kit like the Bloom City nutrient kit mentioned above.

Do nutrients affect the taste of marijuana?

Nutrients will only affect the taste of your cannabis if they’re used improperly. Why does weed taste like nutrients in the first place?

Marijuana nutrients get absorbed through roots or through the leaves if you’re using a foliar spray. A bad taste from any particular nutrient is at risk of remaining in the plant if you keep feeding nutrients too soon before harvest.

You can avoid growing marijuana with nutrient taste by cutting nutrient use completely as you approach harvest time.

You can also “flush” the plant with plain, clean water to help clear any remaining nutrients from the system. That doesn’t mean over-water. It simply means using a normal amount of pH nuetral, nutrient-free water.

Some cannabis growers have even reported larger buds and better taste when they stopped using nutrients as harvest time approached compared to using nutrients right until harvest.

You may notice the cannabis plant leaves turn yellow and die prior to harvest.

That phenomenon may accelerate when you pull the nutrients. That’s due to nutrient deficiency, but that’s exactly what you want as long as you’re close to harvesting the bud.

Why are nutrients important to cannabis plants?

Nutrients and fertilizer are important to your marijuana plants if you want to increase flower quantity and quality at harvest. Nutrients are essential whether you’re growing in plain soil or with hydroponics.

Maintaining your soil’s PH level between 6.5 and 7.0 is another critical factor. This will allow your plants to absorb critical nutrients like nitrogen, phosphorus, potassium (referred to as NPK), calcium, magnesium, boron, copper, iron, manganese and zinc. Before I get to the best nutrients let’s briefly review the types of marijuana nutrients and fertilizers on the market.

Watering Your Cannabis Plants:

Watering is a big part of the cannabis growing and feeding process. While the topic is too big for this post, you should definitely check out my Cannabis Watering Guide to make sure you understand important factors like PPM, pH, and how cannabis nutrients affect the watering process.

Check Out Our Other Growing Tips:

Want more growing tips? Check out my Guide to Maximizing Your Indoor Cannabis Yields. Also check out my guide on Grow Light Hang Height, and Learning about Proper Grow Light Strength (PPFD levels).

FAQ:

References:

Show References