If there’s a single thing that sounds the scariest when starting out growing your own weed – it’s nutrients. But don’t worry. The Canna Dogg is here to make sure it’ll all make sense to you, even if you’re a complete beginner to cannabis nutrients, so we’ll be covering the easiest and simplest approach to cannabis nutrients, but won’t be covering things like hydroponics nutrients, supplements, or micronutrients.

There are affiliate links in here. But, as always, The Canna Dogg only recommends products based on personal experience, the science behind it, as well as the level of customer service provided by the vendor, and affiliate links are clearly marked as such.

Why does cannabis need nutrients?

Let’s start with a tiny, tiny, bit of theory, for good measure. In essence, your plant needs Nitrogen (N), Phospherus (P), Potassium (K), Calcium, Magnesium, and Sulfur. Now, those letters in the brackets are what’s referred to as N-P-K, and will be the most important thing to keep in mind. The actual values are less relevant than the ratio between them is. There are also a bunch of micronutrients your plant needs, but absolutely no point in diving too deep into them right now. In nature, this NPK is naturally obtained through organic material breaking down, in the soil. In our indoor grows, however, we’ll need to provide it ourselves.

The Canna Dogg will assume that you’re growing in soil. Hydroponics nutrients are a whole other ballgame, and we won’t be covering that in this article. 

What type of nutrients does cannabis need?

If you’ve read the Ultimate Beginner’s Guide, you’ll note that The Canna Dogg recommends using slow-release fertilizer for your first grow. It’s a set-and-forget approach to growing, that doesn’t really leave you with a whole lot to do, other than keeping your plant happy and watered. 

That being said, The Canna Dogg knows that slow-release has a bad rep in the marijuana growing community, and will of course provide an alternative. Do note, that there are a million different ways of doing this, though. We’ll be focusing on the easiest, and breaking down exactly what you need. 

For the first two weeks of your grow, you don’t need any nutrients. Your little plant comes with its own inbuilt two-week supply of nutrients, so don’t start applying anything yet.

For the rest of the grow, though, you have a few different options. The Canna Dogg can personally vouch for these brands. Buy a package deal, and go with their recommended feeding schedule. 

  • Reefertilizer. Get their Combo Pack (affiliate link), and follow their recommended schedule. It’s super simple to use, it’s affordable, and it works.
  • I Love Growing Marijuana. Go for the Complete Fertilizer Set (affiliate link), and follow the recommended schedule. 
  • But, probably the best, go down to your local hydroponics store or gardening center if you’re somewhere legal, and ask them! They could probably use your business in these times! Cannabis has shown time and again to grow just fine with general-purpose 20-10-20 fertilizer, and as long as you have your NPK covered, and you’re optimizing your growing environment, you’ll be just fine! You don’t need to stress.

How much should you feed your plant?

As you can see, the above options are all package deals. While still learning how to grow your own weed, always gor for package options. There’s no point in getting down to all the tiny details when it comes to nutrition, just yet, as you’re still in beginning phases of your growing journey. 

Similarly, follow the feeding schedules from whichever of the brands you went with. Remember, that even though the brand gives you instructions for how much fertilizer to mix in with your water per, say 5 liters of water, does not mean that you actually need to give your plant 5 liters of water! In the Beginner’s Guide, The Canna Dogg talks you through how to figure out your watering baseline, and how much water your plants need. So be smart here, and use some simple maths to figure out how much fertilizer to mix in with your water. 

It should be noted, that you should always err on the side of caution, and if in doubt, less is more. It’s far easier to add more nutrients down the line, than it is to reverse a nutrient burn.


This is important. Adding fertilizer to water, changes the pH-levels of the water. Therefore, you must always measure your pH AFTER putting in the fertilizer. Otherwise, your readings will be off. So, mix in your nutrients, give everything a good mixing, and then measure your pH, and adjust accordingly. If you don’t know how to measure/adjust pH, it’s covered here.


Nutrients can build up down in your soil, leading to what’s known as nutrient burn. The Canna Dogg often sees a lot of beginners thinking that more is more, when it comes to nutrients. This is wrong, and may kill your plant. If you suspect that your plant is suffering from a nutrient burn, you’ll want to flush your soil. Flushing means that you’ll be flushing out excess nutrients by literally flushing your soil with clean pH-adjusted water, with no added nutrients. When you progress to growing in things like Coco, or other soilless setups, mastering the art of flushing is essential. For now, though, you just need to be vaguely familiar with the term. 

Final Notes

There are a lot of different “best cannabis nutrients” sites on the interwebs. The vast majority of them are well-written and have good intentions, but some might be trying to sell you stuff you don’t actually need. For your first couple of grows, when growing in soil, you don’t need all those fancy extra supplements. They’re difficult to master, and just not needed yet. So start with the basics, and once you have a few grows under your belt, you can start supplementing with all kinds of things. 

It’s also worth mentioning, that you actually don’t need to buy premade nutrients. You can make your own. That’s not the easiest way to do it though, although it’s probably the cheapest and most organic. The Canna Dogg might do an article on it at a later stage, as making your own fertilizer can actually be quite fun and rewarding!

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