Best Autoflower Nutrients (For All Growth Stages)

cannabis autoflower seedling growing in soil with nutrient chemical symbols displayed

What’s the worst nightmare of a rookie cannabis grower? Getting free seeds and killing them. Been there, done that! In my defense, I’ll say it was a long time ago…

Fortunately, these days the Internet holds the door open for you to access a ton of helpful information and steer clear of rookie mistakes.

On the other hand, autoflowering seeds have made the cannabis grow-at-home experience a lot easier both for beginners and seasoned growers.

In this article, I’ll share everything you need to know about the best autoflower nutrients and how to get the most from your cannabis growing journey.

What are Autoflowering Cannabis Seeds?

Also known as day-neutral cannabis, autoflowering cannabis seeds are varieties that automatically switch from the vegetative stage to the flowering stage based on their maturity and not on the light or dark hours ratio the plant receives.

Photoperiodic cannabis plants need to have a delicate balance of light and dark exposure to reach the flowering stage successfully. This would imply having proper lighting conditions and/or equipment at home, which can be time-consuming and intimidating for beginners.

And that’s one of the main reasons that make autoflowers so great. They can reach flowering in as little as 8 weeks, they’re smaller and will fit in your tiny apartment, and you can produce a solid autoflower yield with these tips.

That said, let’s cut to the chase.

What are the Best Autoflower Nutrients?

best autoflower nutrients

Like photoperiodic cannabis, or any other plant, autoflowers need nutrients to stay alive and grow. You don’t say! Well, this is where things can get trickier. Cannabis plants don’t like to be overfed. Do so, and you can end up with a nutrient burn and your cannabis leaves dying and falling off the plant.

In general terms, we need to feed autoflowers the same nutrients we would provide to photoperiodics, only in smaller amounts. These nutrients are divided into two main groups: macronutrients and micronutrients.


Other than water and air, you’ll need to ensure your plant is getting the right amount of the main macronutrients, which are nitrogen (N), phosphorous (P), and potassium (K). You may think of them as the protein, carbs and fat amounts we need in our human diet.

Nitrogen (N) is vital in all growth stages in the cannabis plant lifecycle, particularly in the vegetative stage. It plays a major role in chlorophyll production (crucial for photosynthesis), amino acids and protein production, and other important biological compounds.

Phosphorous (P) comes quickly into play in the early stages of root development. It also contributes to disease resistance, bud formation, and stem stability.

The third in the essential macronutrient triad is potassium (K). This macronutrient is in charge of osmoregulation and triggers Adenosine Triphosphate (ATP) production.


Your autoflower will also need micronutrients to rise and shine. Although these are required in a much lower amount, it doesn’t mean they’re less important. Think of them like vitamins and minerals in our human diet; we don’t require much of that, but vitamin deficiency can seriously hit our health.

Among these micronutrients, we find:

  • Boron (B), which works on the division of cells.
  • Chlorine (CL), helps the leaves stay firm and strong.
  • Copper (CU), enzyme activator, and photosynthesis booster.
  • Iron (FE), responsible for energy production.
  • Manganese (MN), which protects the roots against pathogens and helps with nitrogen absorption.
  • Molybdenum (MO), an extra hand in the formation of proteins. Zinc (ZN), much needed in the building of growth hormones.

As we have seen, macro and micronutrients play an equally important role in cannabis plant growth. Then, among so many options out there, how to choose the best autoflower nutrient? It will entirely depend on the cultivation you have chosen and the growing medium you are using.

Different Types of Autoflower Nutrients

As the decriminalization movement around marijuana gains ground bit by bit, the market for cannabis enthusiasts also expands. Therefore, there is a wide range of autoflower nutrients to choose from out there.

Some will work better in a compost-based medium, and others will perform their best in hydroponics cultivation. In terms of performance, nutrients can be divided into two categories: organic and inorganic.

Going for organic nutrients is always a wise choice. You won’t be feeding your plant directly when using this type of cannabis fertilizer. Instead, organic nutrients enrich the growing medium with microorganisms.

These microorganisms will feed on the nutrients and break them down for easier absorption. The plant will decide when to feed and which nutrients to absorb. So it’s really difficult to go wrong here.

On the other side, with inorganic nutrients, you feed the plant’s roots the exact amount of nutrients needed. The only problem here is their nutrient needs may vary from one strain to another.

We advise starting with small amounts, experimenting, and finding the best balance for your type of cultivation. You can always add a bit more if your plant shows growth deficiency. However, if you overfeed, taking away nutrients to avoid burning them is definitely more difficult. It’s best to stay on the safe side.

Now, nutrients can also come in solid form or liquid form.

Solid Nutrients

Solid nutrients are usually presented in the form of pellets or powder. These are slow-release nutrients you will mix with your growing medium or use as a top dressing.

This makes the feeding so much easier because you will slowly release nutrients into the medium when watering. So, unless you notice your plant is showing deficiency signs, you don’t really have to put much effort into your autoflower until it’s harvest time.

Liquid Nutrients

Bottled nutrients are probably the most popular type among beginners and seasoned growers. These nutrients come in liquid form; they’re usually synthetic and less expensive, making them a popular choice.

There’s a wide variety of this type of fertilizer, with different brands and qualities. Whichever you choose, it most likely will have the proper NPK ratio recommended for healthy growth.

Slow-release, solid nutrients are more suited for soil grows. On the other hand, liquid fertilizers are best for hydroponics and other soilless growing mediums, as the nutrients will become directly available for plants.

Autoflower Nutrients for Each Growth Stage

Although breeding autoflowers is great because they tend to be resistant and demand less attention and nutrients, it’s always a good idea to know their nutrition needs in each growth stage.

cannabis plant growth sequence from seed to seedling with multiple branches and leaves

Seedling Stage

During the first two weeks, your autoflower will be in a very fragile state. It’s developing its root system to grow. Overfeeding in this stage may come with disastrous consequences.

We advise just watering during this initial period. However, if you are feeding, you can start with 1/8 of the recommended amount of nutrients. The recommended NPK ratio would be 2:1:2.

cannabis autoflower seedling in soil with its first 4 leaves

Vegetative Stage

Actually, there really isn’t an autoflower vegetative stage, as they won’t need a change in the light cycle to flower. Instead, autos basically jump from seedling to flowering.

However, from the first set of true leaves until the flowering, you’ll need to start feeding more nutrients to your plant. Make sure you’re adding more nitrogen in this stage, as this will help the plant develop strong branches and leaves.

The recommended NPK ratio would be 10:5:5.

Pre-flowering Stage

When your plant experiments an explosive growth, that means it’s getting ready to flower, also known as the pre-flowering stage.

Most autoflowers can live well through the first pre-flowering weeks with vegetative nutrients. It’s not a great idea to increase even further the nitrogen amount, as it can cause the plant to grow too many leaves.

However, increasing the phosphorous amount will help the plant move on to flower production. The recommended NPK ratio would be 10:10:5.

Flowering Stage

close-up of autoflower plant with leaves and pistils

Once your autoflower has developed into full bloom, you can start reducing nitrogen and increasing phosphorous and potassium until late flowering. This will help with the bud production. If you’ve been heavily feeding your auto, now it’s a good time to start reducing the nutrient amounts.

Finally, we advise giving only water to the plant for the last couple of days or the last week before harvest. The recommended NPK ratio during flowering would be 5:15:10.

Optimal pH Levels for Autoflowers

And you’re probably thinking you’re good to go and start growing your autos. And you are, just don’t forget about pH! (Seriously, now what?) Easy, it’s not rocket science.

pH stands for potential hydrogen and is basically a balance between hydrogen and hydroxide ions. The pH scale ranges from 1 to 14, with 7 being the neutral pH. Values ranging from 1 to 7 are considered acidic, while values from 7 to 14 are considered alkaline.

pH level scale from 0 to 14

And why do you care about this? Because the optimal pH level for cannabis cultivation should be between 6.0-7.0 for soil mediums and 5.5-6.5 for hydroponics.

Thus, you need to get yourself a pH test kit or invest in a professional pH pen that will give you accurate readings every time you dip it into your water or nutrient solution. Class dismissed!

Wrapping Up

As we have seen, feeding the proper nutrients to your autoflower will likely vary according to your growing medium, cannabis strain, genetics, and other factors.

Autos tend to be resistant, one of the main reasons they have become so popular. However, always keep in mind the secret formula to perfect growth, and a decent yield lies in spending quality daily time with your plant.

Find out what their needs are, see how well it’s reacting to the nutrient solution, and figure out if you need to increase or reduce the NPK ratio you’re using for your particular strain.

Hopefully, you found this article helpful. Happy growing!

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