The full guide to the best cannabis nutrients

The full guide to the best cannabis nutrients
Miguel Antonio Ordoñez

Check out our guide to the most important macro and micro nutrients, that healthy marijuana plants need to reach full potential.

Cannabis plants actually use the process of photosynthesis to convert light into energy. The marijuana grower must be aware of this key factor, as ignorance of this fact leads many to the phoney conclusion, that massive doses of chemical fertilisers are the only way to secure a heavy weed harvest.

Many variables must be considered in order to select the right cannabis nutrients and administer them at the right time. Your choice of cannabis strain to crop and cultivation method are the two most significant elements.

The goal is to integrate the appropriate fertilisers for the cultivation medium and apply in doses suitable for the specific cannabis strains.


Cannabis base nutrients

The three letters you will see prominently displayed on every brand of cannabis nutrients and supplements are the N, P, and K values. This represents the ratio of nitrogen, phosphorus, and potassium respectively.

Base nutrients are the primary fertiliser feeds, that the grower will add to water to enrich it with the macronutrients and, provided it’s a quality product, most of the necessary trace elements like calcium, magnesium and a host of other required micronutrients.

In simple terms more N is desirable during vegetative growth, with low levels of P and K. As cannabis plants transition into the flowering stage, P and K must steadily be increased, while N is gradually depleted, swinging the ratios in the opposite direction. That’s why base nutrients come in separate blends for specific use during vegetative growth and bloom.

Soil growers can usually stick with plain water for the first 2-3 weeks, as even light mix soils have sufficient quantities of both macro- and micronutrients to nurse an infant cannabis plant at least through the seedling stage and into vegetative growth.

However, hydroponic and coco cultivators will need to add base nutrients at approximately 25% strength from early on in the grow, as the medium is not pre-fertilised and inert.

To avoid overfertilisation of cannabis seedlings, many such growers will start their beans off in pre-fertilised rooting cubes, that only require plain water until roots begin to protrude from the cube, indicating it’s time for a transplant.


Cannabis nutrient supplements are of value to incorporate in every growers feeding schedule. Unless you’re an outdoor organic purist, that mixes their own super soil to grandmaster grower standard, then you need to take supplements seriously.

Supplements can play a role in the entire cannabis life cycle. Beneficial fungi and microorganisms like mycorrhizae can be inexpensively added to rooting medium to promote the development of a healthy root zone.

From the very beginning, once the cannabis seed germinates, it will be encouraged to root well, as the mycorrhizae will form a symbiotic relationship with the root zone.

Enzymes are perhaps the most important supplement to include throughout vegetative growth and the bloom phase. These catalysts effectively serve to unlock the full potential of your cannabis plants.

Furthermore, enzymes help the root zone to thrive and facilitate the absorption of the macro- and micronutrients. Often overlooked and omitted from feeding schedules, but enzymes really are vital.

Liquid silica is yet another crucial cannabis supplement, especially for hydro growers. Adding a light weekly dose of silica throughout your plant’s lifecycle is a great preventative measure to ward off a host of nasty pests and pathogens.

Silica strengthens the cell walls and is the best way to toughen up a cannabis plant. Vigorous healthy plants are less susceptible to disease and the dreaded bud rot is less likely to strike cannabis plants pumped up on liquid silica.

Organic molasses can be found cheaply in most supermarkets and it’s actually a cannabis super-supplement rich in trace elements. Nothing keeps the microorganisms in soil happier. Not really an option for hydro growers, as it’s sure to clog up something.

But for the organic grower, we recommend you make molasses your new best friend. Fantastically effective in the later bloom stages to assist resin production and virtually guarantees full flavour buds.


Cannabis bloom boosters are where the grower must be discerning. Some strains respond very well to a particular brand of bloom booster and not so well to a rival company’s product. Other strains don’t really need these products at all.

As you become more familiar with various cannabis strains and gain more growing experience through experimentation, you will decide which product best suits your grow op. Too much of anything can be a bad thing and too much P and K will burn buds rather than boost production.


Foliar feeding

Marijuana can also drink up nutrients through its leaves and foliar feeding is a real option until the plant starts to grow buds. The best time to apply a foliar feeding is within the first two hours of the light cycle to prevent the wet leaves getting light burn blotches.

In fact, it’s best to spray down the underside of leaves as much as possible and don’t get carried away soaking the plants or mold could be a problem.

During vegetative growth and up to about week 3 of flowering you can foliar feed and if excess heat is an issue a foliar feed can be just the tonic. It’s best to discontinue foliar feeding in mid-flowering at the latest, as moisture and flowers are a recipe for bud rot.


Don't forget to flush your plants with pure water or a light dose of flushing solution for one week at a minimum, otherwise your stash might taste like a bottle of cannabis nutrients rather than chronic.

Miguel Antonio Ordoñez
Miguel Antonio Ordoñez

Miguel Ordoñez is a long-time writer by trade. Utilizing his AB Mass Media and Communications degree, he has 13 years of experience and counting. He’s covered a wide array of topics, with passion lying in combat sports, mental health, and of course, cannabis.