Optimal NPK Ratio: Growing Cannabis at Home

One of the most important things that you need to do if you plan on growing cannabis plants at home is to provide them with the proper NPK ratio within your nutrient solution. If the nutrient solution you are providing your plants with does not have the appropriate ratio of nutrients, especially in terms of the specific growth stage of the cannabis plant, it may cause some problems.

Tap water itself does not contain a nearly enough nutrients to provide marijuana plants with the fuel they need to grow properly, especially not when it comes to the plants roots. In terms of overall nutrient uptake, you need to remember that the pH level for your nutrient solution is very important as well.

Even if you have the optimal NPK ratio in your nutrient solution, if the pH level is wrong, it will lead to what is known as nutrient lockout, or a complete lack of nutrient uptake.

Therefore, not only do you need to ensure that the nutrient levels are ideal, but the pH level as well. Something else we will take a look at today is what can happen when your cannabis plants get too many nutrients or too few nutrients.

Growing marijuana and cannabis cultivation in general can be quite difficult, but growing cannabis can be fun if you do it properly, and the big part of this is the NPK ratio and the nutrients that you provide your plants with.

What is the NPK Ratio?

The NPK ratio for cannabis plants is in regard to the three main nutrients that your marijuana plants need to survive. NPK stands for nitrogen, phosphorus, and potassium, by far the three most important nutrients that cannabis plants need to grow. Each of these three main nutrients provides different benefits and functions for your weed plants.

If the nutrient levels of all three are not appropriate for the growth stage in question, then your cannabis plant may run into nutrient deficiencies, or you may be giving them too many nutrients. As you can tell, the amount of nutrients that you provide your plants with is very important.

Importance of the NPK Ratio

All three of the nutrients mentioned above, nitrogen, potassium, and phosphorus, are extremely important for your cannabis plants in one way or another. Let’s take a quick look at why these nutrients are so important for your cannabis plants.

Nitrogen for Cannabis Plants

Nitrogen is by far one of the most important nutrients for your cannabis plants, particularly during the seedling and vegetative stages. During the seedling stages and vegetative growth stage of your marijuana plant, nitrogen is very important, because it allows for the fast and vigorous growth of foliage, including branches and leaves.

Then, if we are talking about the flowering stage of your weed plant, nitrogen is quite important as well, because some foliage will continue to grow. However, during the flowering stage, nitrogen levels do need to be reduced significantly in order to allow for proper bud formation and to prevent excessive leaf growth from occurring.

Phosphorus for Weed Plants

We then have phosphorus, which is another very important element that is needed in your nutrient solution. Phosphorus is an important element for your cannabis during the seedling and vegetative stages because it supports great plant’s vitality, early growth, and fantastic root development. Then, during the flowering stage, phosphorus becomes even more important, as it is important for developing dense buds as well as overall potency.

Potassium for Marijuana Plants

Finally, the third most important element for your cannabis plants is potassium. If we are talking about the vegetative stage of growth of your weed plant, potassium helps with water intake, stress tolerance, and photosynthesis. Your plant needs it in order to convert fuel into the energy it needs to grow. Then, during the flowering stage, potassium is also very important, as it helps with resin production, but development, and nutrient uptake.

Optimal NPK Ratios for the Cannabis Plant

The main point of today is of course to discuss what the optimal NPK ratios for your weed plants are during various stages of growth, so let’s do that right now.

NPK Ratio for Cannabis in the Vegetative Stage

When your plant is in the seedling stage, as well as in the vegetative stage of growth, an optimal NPK ratio is either 3:1:2 pr 2:1:2, depending on the growing medium you are using and the exact plant you have. Some strains as well as some growing mediums, particularly if you are using water as opposed to soil, will require slightly more nitrogen to allow for good foliage development.

NPK Ratio for Cannabis in the Flowering Stage

If your plant is in a flowering stage of growth, you need to cut back the nitrogen levels, while also increasing both potassium and phosphorus levels. The ideal NPK ratio for weed plants in their flowering stage is either 1:2:3 or 1:3:3. Once again, if you are growing in a medium that does not contain many nutrients, you’ll want to go with the second of those ideal nutrient ratios, to provide your plants with the maximum amount of nutrients that they need to survive and thrive.

Other Important Nutrients for Cannabis Growth

What many people don’t realize is that although those three macro nutrients the NPK nutrients, are very important, cannabis also needs various other micronutrients. These include the following:

• Magnesium
• Calcium
• Iron

More often than not, people provide their cannabis plants with plenty of the NPK nutrients, but forget to other important ones, magnesium and calcium, which can often lead to either a magnesium deficiency or a calcium deficiency. This brings us to our next point, being able to identify various nutrient deficiencies.

Cannabis Nutrient Deficiencies

When it comes to the proper NPK ratio, if you aren’t giving your plants enough of these nutrients, there are various deficiencies or nutrient deficiencies that may occur. Therefore, in order to continuously provide your plants with the best nutrient solution possible, you need to be able to identify the various signs of different nutrient deficiencies.

Nitrogen Deficiency

With a nitrogen deficiency, you’ll notice that old leaves turn yellow or pale green and starts to tip inward, with lower leaves dropping quite early. You’ll also notice stunted plant growth, along with spin and spend the leaves.

Phosphorus Deficiency

A phosphorus deficiency is characterized by leaves turning very dark green along with a purple tint, particularly on the underside of the leaves. The leaves may also have a bluish tint, and may look very shiny. You should also notice that the plant is experiencing stunted growth, along with fewer than normal flowers.

Potassium Deficiency

If your plant has a potassium deficiency, you may notice that the margins of the leaves start to curl or look like they are burned, with older leaves developing brown spots or turning yellow, which start from the edges. You will also notice stunted plant growth.

Magnesium Deficiency

If your weed plants are suffering from magnesium deficiencies, you’ll start to notice a yellowing between the veins on the older leaves, with leaves also becoming brittle and curling. You will notice that The symptoms start at the edges of the leaves.

Calcium Deficiency

If your cannabis plant is suffering from a calcium deficiency, you may notice that the new leaves start becoming to start distorted or dying off. You may also see that leaves start twisting or clawing.

Iron Deficiency

If your cannabis plant is suffering from an iron deficiency, you’ll notice that the veins between the leaves start to turn yellow. You may also notice that the leaves start to develop very pale network patterns.

Zinc Deficiency

If your marijuana plants are suffering from zinc deficiencies, you may see the younger leaves suffering from interveinal chlorosis, along with distorted leaves and a smaller leaf size. You might also notice that the leaves start to curl or form small rosettes, along with early stunted growth.

Creating a Nutrient Solution

First things first, when creating a nutrient solution, if you are using tap water, you’ll want to use a water conditioner to remove chlorine. You may also just let the water sit out for up to 24 hours. However, if you want the best possible water for your plants, using a reverse osmosis water is recommended. A reverse osmosis water is specially treated to ensure that it does not contain high levels of chlorine, salt, or other such substances.

On that note, always be sure to take the appropriate steps to prevent a salt buildup from occurring, because this can also spell disaster for your plants. Just remember however that reverse osmosis water does not have really any nutrients present at all, which means that you’ll need to add those nutrients into the water.

This is when you need to go out and choose the best possible nutrient solution for you, adhering to the guidelines and principles which we discussed in the above sections. However, once you have added all the nutrients into the water, you still need to take a few more steps before you give it to your plants.

Always Measure PPM and pH

Before you give your nutrient solution to your plants, so that you can ensure that the root system is in optimal health, you need to measure pH levels. pH levels in your nutrient solution it should be between 5.5 and 6.5, particularly if we are talking about growing cannabis in soil.

The root zone of your cannabis plant needs to have a pH level of roughly 6.0, or else they will not be able to take up nutrients as efficiently anymore. If a nutrient lockout occurs due to an ideal pH levels, it will likely cause your marijuana plants to die.

Importance of the Type of Growing Medium

Something else that is important to note here is that the growing medium you use makes a big difference as well, and here we are talking mainly about the differences between growing in soil and growing using a hydroponics of water system.

The issue here is that when it comes to the growing medium, soil usually contains a good deal of nutrients. This can in many cases be beneficial, because it means that you need to purchase less nutrients, particularly for the first month or two of growth.

However, it can also be a challenge, because when creating a nutrient solution for your plants, you have to take into account the current nutrients already present in the soil. Generally speaking, plants using a growing medium of soil will require less nutrients than those growing in water. If you have a hydroponics system, you’ll need to add quite a bit of nutrients into that reservoir water to provide your cannabis plants with the nutrients they need to survive and thrive.

TDS and PPM

You’ll probably want to get a TDS meter so you can measure the TDS levels in your soil or other growing medium. For the record, the TDS levels or total dissolved solids, should be kept between 600 and 800.

The total dissolved solids in your nutrient solution, as well as in the soil in general, is very important to measure.

You’ll also want to get yourself a PPM meter so you can measure PPM or parts per million levels of the mineral content in the soil or water.

A PPM reading of roughly 800 or 900 is ideal during the vegetative stage, whereas a reading of around 1000 PPM is ideal for the flowering stage.

Having either too many or too few total dissolved solids or minerals in your watering solution can spell disaster as far as the nutrient uptake of your plant’s roots. Most TDS Meters are quite affordable, so this shouldn’t be a problem!

Conclusion

keep in mind that if your plants receive the proper NPK ratios, they should do just fine, and if you are planning to grow cannabis at home, adding nutrients is very important, or else they will not thrive.

Remember that besides the NPK nutrients, there are a few other elements that you will need in order to grow marijuana, such as calcium and magnesium, which means that you’ll likely need more fertilizers than you first thought.

That said, as long as you keep track of the ratios, you measure the pH, measure the PPM, and provide your plans with plenty of fresh water, they should grow just fine.