NPK Beginners Guide
NPK stands for nitrogen, phosphorus, and potassium. These three numbers represent the ratio of N, P, and K in your fertilizer. Every main mix (complete balance) fertilizer will have these numbers clearly displayed, always in the same order.
Not all fertilizers are complete balanced fertilizers, however. Different ratios of NPK serve different needs. For instance, a blooming mix might have low to no nitrogen in the mix.
So what do each of these nutrients do?
- Nitrogen is what makes your plants green, big, and strong. It is the absolute most important nutrient in the solution.
- Phosphorus is important for blooming; it plays a role in all of the reproductive roles of your plant.
- Potassium is important to plant photosynthesis, CO2 uptake, activation of plant enzymes, and water uptake. It is important for building strong stems and seeds.
N, P, and K are not the only nutrient that your plant needs. Micronutrients are required in much smaller quantities. A complete and balanced fertilizer will almost always include the micronutrients.
The NPK in your fertilizer is not present in their pure elemental form. Plants can only take up certain compounds with these nutrients in them. Fertilizers also sometimes have multiple forms in the fertilizers. These are listed on the label of the formula.
A Word on Organic Fertilizers
Many sources of fertilizers are synthetically derived. You might be wondering if there’s an organic option. The answer is yes, but realize that more is needed to use an organic solution. To use organic fertilizers in a hydroponic setup, you need a very strong microbial community in your system. The microbes are what drives organic growing. They cycle the nutrients and turn them into a form that the plants can use. So if you don’t have a strong community, this won’t work.
Another drawback is that it takes time (6-18 weeks) to culture the microbial community.
A final drawback of organic hydroponics is that some solutions do stink. When you put a lot of organic compounds into water, you can end up with lots of anaerobic microbes that produce horrible smells.
If you’re using a solution with low nutrient, but not for a blooming crop, you should supplement nitrogen in another part of the solution. CaNO3, calcium nitrate can be used, to bring up the nitrogen ratios for our lettuce crops.
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Finding the right balance of nutrients for your plants is extremely important however buying pre-made mixes and following the very explicit instructions they come with will make the job a whole lot easier. All of the products listed below come highly recommended.
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