Ever read something about NPK fertilizer ratio & have no clue what it meant? That changes after reading this article.
Understanding how plant nutrition works is extremely important for hydroponics growers because when you work with a soil-less system, you are not just supplementing the plants with extra fertilizer: you are providing everything that the plants need.
Soil naturally contains minerals and decaying organic matter, so the application of fertilizers only provides additional nutrition to the crops. In a hydroponics system, all you really have is water until you begin adding the nutrient solution to the system.
Plants consume two types of nutrients that differ mainly in the amounts they are needed to sustain plant life. The nutrients that plants consume in higher quantities are called macronutrients, while nutrients that are absorbed in far lower quantities but remain essential to plant life are called micronutrients.
NPK is actually an acronym that refers to three important plant nutrients: nitrogen, phosphorous, and the third one being potassium. These three represent the top three macronutrients that plants consume in heightened quantities throughout the growing season.
The focus getting the NPK fertilizer ratio right is to provide a suitable amount of nutrients to plants, and while micronutrients are equally important, they are not the focus.
When you go out to buy fertilizer for your plants you will see that each brand of fertilizer will have its own NPK ratio. The NPK ratio represents the amount or percentage of nitrogen, phosphorous, and potassium in that particular fertilizer.
Fertilizes are definitely not made equal, and some fertilizers are more ideal than others. Understanding the different NPK ratios will definitely give your hydroponics efforts a boost as providing the right nutrition to plants will produce a better harvest and healthier plants overall.
Reading the NPK ratio is easy. Let’s say that a fertilizer states that its NPK ratio is 7-9-5. What this simply means is that your plants will be getting seven percent nitrogen, nine percent phosphorous, and five percent potassium.
This figure is in relation to the bigger mix of nutrients contained in the fertilizers.
A single fertilizer can have more than twenty different plant nutrients within, so a fertilizer ratio corresponding to 9% of the mixture is a big deal because you have to look at the proportion of the nutrient vis a vis the rest of the nutrients.
The common 7-9-5 ratio is considered the best NPK ratio for the vegetative state of plants. Fertilizers that utilize this ratio are generally called “grow” fertilizers as they help develop lush and plentiful foliage, dark, green leaves, etc.
The increased amount of nitrogen in this ratio is responsible for boosting the vegetative state of crops. Additional nitrogen can also help improve the overall growth of the plant until harvest. If you want to speed up the healthy maturation of your crops, use hydroponics fertilizers or nutrient solutions that are marked “grow” or “vegetative.”
The flowering stage is the time when crops begin to produce their flowers, fruits, and vegetable components. Depending on what plants you are actually taking care of in your system, flowering/fruiting may mean different things for each cultivar.
It is during this phase in the growth of plants that hydroponics growers ready themselves for the impending harvest. Agriculture has gone a long, long way since the sixties, and growers now have access to a wide range of fertilizers and compounds that help control when the different growth phases of plants actually occur.
During the flowering/fruit stage, plants generally need more phosphorous than nitrogen.
Phosphorous is also needed for the growth of healthy root structures, which are also essential when the plants are beginning to grow fruits and flowers. In addition to phosphorous, the more important nutrient to watch out for would be potassium.
It would be helpful at this stage to scope out a fertilizer that has 0-0-3 NPK ratio that is geared specifically for producing abundant amounts of fruits in most plants. One-part formulations designed for fruit or bloom can also be used as these have been customized to improve fruit production.
You can also try to find a general use fertilizer with an NPK ratio of 5-15-14. As you may have noticed, the amount of nitrogen has been drastically reduced to just five percent, while phosphorous and potassium are increased to fifteen percent and fourteen percent.
Why don’t plants need as much nitrogen during the flowering/fruiting phase? The reason for this is that plants during the vegetative stage tend to absorb and store sufficient nitrogen for the long haul. So giving your plants more nitrogen will not benefit your crops – but potassium and phosphorous will.
The chemistry behind NPK ratio is so varied that it is impossible to list down all the ratios that are in use right now in hydroponics setups around the world. However, we can discuss some of the more popular ones so you will have an idea when you start shopping for some more liquid fertilizers.
There is a general purpose ratio that can be used for the vegetative state of crops and can be substituted for the bloom formula if there isn’t enough of it/it isn’t available.
The NPK ratio of general purpose fertilizers is 10-10-10. General purpose fertilizers should only be used when there is an established system already and you only want to supplement the system with equal portions of nitrogen, phosphorous, and potassium.
Using Bloom Boosters?
Now you may have heard of “bloom boosters” or hyper-chargers that can be used during the fruiting stage of plants. Bloom boosters are actually risky when you are not fully familiar with how they affect different cultivars, as the NPK ratio of bloom boosters is 0-50-30.
The amount of phosphorous and potassium in these mixtures are huge and when used improperly, can likely change the pH level of a hydroponics system and can even cause nutrient lock. Experts warn that misusing bloom boosters can actually create the opposite of what you may have been thinking of.
If your plants end up being given too much and you are not able to balance the system, you may end up with a significantly reduced harvest, with smaller fruits and stunted growths.
Again, this can be directly caused by nutrient lock, which occurs when there is just too many nutrients in the system. The plants shut down and ironically, malnutrition occurs. Being so close to harvest, this can be a huge disaster because all season long, you have been waiting for harvest and this is the worst time for such a condition to occur.
Crops don’t jump from the vegetative (or vertical growth stage) to the blooming/fruiting stage instantly. There is actually a middle phase that many websites tend to omit: the transition phase.
The transition phase is the gradual middle stage that eases the plants from the vegetative stage to the blooming/fruiting stage. During this stage, we recommend that you combine your vegetative formula with your bloom formula. Take fifty percent from each batch and combine to help speed up the transition to blooming/fruiting.
How would you know that the vegetative stage of your plants is over? That’s easy: simply check if your plants are still growing in height. When the height building ceases, that means your plants are plenty ready to start growing fruits or flowers.
Be excited! Because this is what we have been waiting for the whole season: your crops are finally getting ready to bear fruit. When you are sure that the vegetative stage is finally over, what you can do is shift completely to your chose fruiting/blooming formula to encourage maximum yield in your system.