NPK, nutrients for cannabis

Indoor Growing: The Basics of N-P-K and Ca-Mg-Fe

What are the best nutrients for cannabis? Beyond the essential N-P-K ratio, what other nutrients do your plants need to sprout, veg, and bloom?

It turns out, the best hydroponics nutrients for cannabis contain more than just these fundamental building blocks of nitrogen (N), phosphorus (P), and potassium (K). You’ll also need to ensure your plants have access to calcium, magnesium, and iron. 

Delivered in the right ratio, at the right time, and under the right conditions, these macro and micronutrients work together to build cells, facilitate photosynthesis, and enhance plant well-being. 

N-P-K: Macronutrients for Cannabis

The foundation of plant life revolves around three specific nutrients: nitrogen (N), phosphorus (P), and potassium (K). You’ll find these listed in the label of almost all basic nutrient formulas, whether you are growing cannabis, veggies, or flowers. 

Typically, these macronutrients are expressed in a ratio. You’ll see on the labels numbers like 1:1:1 or 0:3:3 indicating how much N-P-K the product contains. 

This ratio is a crucial indicator for the best bloom nutrients for cannabis or veg. Why? Because all plants require slightly different nutrient recipes, depending on where they are at in their growth cycle. 

Nitrogen (N)

Nitrogen is the primary pillar of all plant life. According to one study, nitrogen plays many roles for plant growth, including for “protein, chlorophyll, and nucleic acid synthesis.” Thus, without an ongoing supply of nitrogen, plant function and production are severely stunted.

During the vegetative stage of development, you’ll want to use nutrients with a higher N value, like you’ll find in the Biocanna Bio Vega 3:1:5 formula.

Because nitrogen plays a critical role in building the structure of the plant, it’s essential for achieving that bushy growth you want to see during veg. During the flowering stage, the best bloom nutrients for cannabis contain a lower nitrogen level.

Phosphorus (P)

Phosphorus, another foundational macronutrient, facilitates healthy plant metabolism, photosynthesis, and better overall uptake of other nutrients. An adequate supply of P in the early stages of growth help promote root development, which is so important for the plant’s overall health. 

Generally speaking, your plants will need a mid-range supply of phosphorus in the vegetative stage and slightly more during flower. 

Potassium (K)

The final macronutrient is potassium or K. Although it benefits many areas of plant health, the most notable are its benefits for pest and disease resistance, improvements to water usage. In flower, it also boosts bud size. 

Interestingly, potassium can help make your plants more cold-hardy. So much so that some growers use this macronutrient to winterize their plants.

Unlike nitrogen and phosphorus, it’s critical no matter what stage of growth you are in. Cannabis requires relatively high levels of K in both the veg to stimulate early growth and flower stages to increase bud size. Once again, Bio Canna Bio Vega 3:1:5 is an ideal option for higher K values required in bloom.

Ca, Mg, Fe: Micronutrients

hands digging into a bag of fertilizer, NPK
Sometimes, all the nutrients are available, but the environment is locking them out.

While most nutrient labels loudly display the N-P-K values, you’ll also want to ensure your plants are getting the necessary supply of micronutrients, including calcium (Ca), Magnesium (Mg), and Iron (Fe).

Micronutrients pose more of a challenge for hydroponic growers, who use reverse osmosis. These secondary nutrients often exist in soil and substrate. Still, they are not always immediately available (absorbable) until broken down by the beneficial microbes, bacteria, and fungi) living in symbiosis with your plants. 

Calcium (Ca)

Your plants might not need a lot of calcium during their life cycle, but you’ll still need to consider calcium, as it supplies the building blocks for some of the most critical components of plant life. 

Calcium is required for plant cellular signaling, hormone and enzyme regulation, photosynthesis, and even gene expression. As such, plants use it in both veg and flower. 

Hydroponic growers can struggle with calcium deficiencies more than soil-based growers. An excess of other nutrients or issues with pH can make it difficult for plants to uptake Calcium.

Magnesium (Mg)

Another essential secondary nutrient is magnesium. Plants use magnesium for the photosynthetic process, as well as as a component for creating chlorophyll molecules. Although cannabis plants require magnesium throughout their life cycle, magnesium lockout is most common during flower because of an excess of phosphorus and potassium (supplied in higher levels during this time).

Alongside calcium, it is more of a concern for hydroponic growers than soil-based ones, especially for reverse-osmosis systems. 

Iron (Fe)

Like magnesium, your plants need iron to create chlorophyll. It’s a building block required for photosynthesis. If there isn’t enough trace iron in your system, plants will also struggle to absorb enough nitrogen.

Iron deficiency is one of the most common issues hydroponic growers face and one of the most challenging to diagnose. Usually, it all boils down to nutrient lockout and an elevated pH level.

Why CalMag?

You’ll often find calcium, magnesium, and iron supplied together in a CalMag additive because these components work together on the same processes. If you are suffering from a nutrient deficiency for any of these three compounds, chances are you’ll see a deficiency for all of them, which is why they are sold together as a beneficial additive.

The Building Blocks to Life Micro and Macronutrients 

As many cultivators have discovered, it’s not always about sourcing the best nutrients for cannabis. It’s about getting the recipes right. Too much or too little of any of the nutrients can influence the absorption of the others. 

On top of this, pH creates an additional layer of complication to nutrient uptake. If your growth is outside the optimal pH level, your plants will suffer from nutrient toxicity or, alternatively, deficiency. 

HydroGuide aims to make indoor growing easy. No steep learning curve, no guessing, HydroGuide delivers detailed nutrient recipes, nutrient schedules, and tips that anyone can follow. With a helpful Grow App, Community Forum, and Shop, we are demystifying indoor growing.

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