For whom is this tool?
- You are hobby grower and you’re using a fertilizer multipart setup for your plants?
- You’re sticking to the manufactors feeding plan and dosage suggestions but your plant does not develop well?
- It is not unlikely that your plant does not get the proper nutrient-composition.
- The N-P-K Nutrient Calculator calculates a proper nutrient solution, based on your plants N-P-K need and your fertilizers ingridiences.
The idea about the Nutrient Calculator
Many hobby growers are using multipart nutrient fertilizers such as GHE-3-Part or Advanced-Nutrients-3-Part. Those multipart fertilizers are providing your plant with a great composition of all the nutrients it needs to develop properly. The supply with macro-nutrients is very well covered by those fertilizers and you usually don’t have to worry about any excess or deficiency caused by makro-nutrients. Thus the Nutrient Calculator focusses on the micro-nutrients N-P-K as it is very likely that damage by over- and underfeeding is caused by those elements.
The discussion about dosing fertilizers especially in a hydroponical environment is being lead actively on the internet. Most writers do agree that using a smaller dosage than recommended by the manufactor is a good idea. And of course there are other people reporting something completly different. But why is that? One of the main reasons why manufactors are not even able to suggest a proper dosage instruction or even a feeding plan is: They don’t know what you are growing!
Lifecycle
Each plant has a unique nutrient requirement profile depending on many factors Even plants sharing the same kind can have different requirements. Factors such as location, height, media, climate, and the plants lifecycle phases are determing its nutrient requirements.
Most flowering plants are roughly going through the same phases of a common life- or season cycle. Very roughly those phases are:
- Vegetative phase
- Flowering phase
- Ripening phase
It is important to know how the specific lifecycle profile looks like. Which phases are important and how long does any phase last? As the plants requirements are changing once it is changing the phase, the composition of the nutrient solution must be adjusted. Once you understand the plant’s life cycle profile, you can calculate when a change needs to be made to offer the new nutrient composition as soon as it is needed.
[A sample 12 week – lifecycle showing the distribution and length of relevant phases and transitional phases.]
Requirements profile
During each stage of its lifecycle very specific processes do happen within the plant. The requirements for nutrients is depending on what the plant is actueally doing. In the vegetative phase e.a. the plant tends building up foilage and streches out. Wherein the flowering phase the plant might excessively build flowers for reproduction. Building leaves needs more nitrogen (N) and building flowers might take more phosphorus (P).
Once growing a plantit is important to know about three very important key informations:
- How does the lifecycle profile look like?
- Which nutrient requirements profile does the plant have at each specific phase of its lifecycle?
- How much of required nutrients (EC) will the plant consume?
Once you know about those three informational patterns you can derive what exactly has do be given to the plant at any point of its lifecycle. Using this specific data with the Nutrient Calculator allows you to precisely adjust the ratio and dosage of your fertilizer parts in order to get a perfect nutrient solution.
[A sample 12 week – lifecycle showing the real requirements for N-P-K resulting in a specific EC]
Importance of a proper nutrient balance
One might think that offering evrything which could be nessesary for a plant just like on a buffet sounds like a good feeding plan. However, ignoring the importance of accurate nutrient balance leads to an imbalance, which is often the start of other problems.
It is important to have the N-P-K ratio in your nutrient solution exactly corrosponing to the plants N-P-K requirements ad this specific point. Unused salts might cause an excess. An ongoing excess can lead to salt deposits which can cause a nutrient lockout that might look like a deficiency. Not unlikely an assumed deficiency is caused by a lockout. This can become a very confusing thing and makes it very hard to diagnose the plants real issue. Overfeeding is what often happens to hobby growers whom are using multipart nutrients. You can avoid this by knowing your plants key data, and setting up a proper feeding plan.
[A sample 12 week – lifecycle showing the required N-P-K ratio at each week]
How does the Nutrient Calculator work?
In order to use the Nutriernt Calculator you need to do some preperations. Knowledge about your plant and your tap water as well as detailed informations about your fertilizers are mandatory.
Phase specific requirements profile of your plant
First of all you want to know about your plants lifecycle and its specific requirements profile. This is propably an information which might not be easy to obtain. Though science provides us with a lot of prescious data. You will find such informations on the internet by doing a little research.
Now you should then know about:
- The phases of the plants lifecycle and how long each pases does last
- The nutrient ratio the plant needs at each specific phase of its lifecycle
Knowing about this data lets you fill out the table for the N-P-K requirements profile.
[The required N-P-K ratio at different phases of the lifecycle]
Facts about your fertilizer parts
N-P-K ratio
Manufactors are indicating the ratio of micro nutrients by the N-P-K Value shown on the label. A label saying 5-1-6 e.a. means that the fetrilizer contains 5 parts nitrogen (N), 1 parts phosphorus (P) and 6 parts potassium (K). Each of the three numbers also represents the percentage of that nutrient in the composition of the fertilizer – 5%(N) – 1%(P) – 6%(K).
[The fertilizers N-P-K ratios]
The fertilizers “potentials”
Except of the indicated micro nutrients N-P-K you will find a bunch of macro nutrients in your fertilizer. Each of those macro nutriens such as Mg, Mn, Ca, S, etc. is actually salt as well and lets the ppm of the nutrient solution rise. Thus you can’t derive your fertilizers effect on the EC just from the given N-P-K values.
The concentration of your nutrient solution is a cruical value and you need to know about the “potentials” of your fertilizer. In other words: How many salt / fertilizer molecules does the fertilizer really add to your water? Unfortunately this value is not being provided by the manufactor. In order to obtain this value you need to have a device which can measure the concentration of nutrients in water.
Water conducts electricity. The electric conductivity of water though depends on how many salt molecules are dissolved in the water. R/o water does not contain any salt, therefore the electric conductivity (EC) lies at almost zero MicroSiemens (µS). The more salt, which is actually nutrients, is dissolved in the water the higher the the EC becomes. The electric conductivity lets you derive how many molekules are dissolved in the solution. This value is known as parts-per-million (ppm). EC and ppm does actually tell you the same.
Take 1 liter of your tap water and measure the EC. R/o water should have something between 0 µS and 50 µS. Tap water might have up to 500 µS. Apply 1 ml of your fertilizer to 1 liter of your water, measure the EC again. Substract the initial EC and you have your fertilizers potential.
Once you know about these values, you can fill out the table for “fertilizer facts”:
[The fertilizers effects on the EC]
Calculating the precise mixing ratio
The sliders can be used to perfectly adapt the mix to the needs of the plant.
Manufactors are usually suggesting a rough mixing ratio for their multipart nutrients. It is a good idea to start having the sliders initially at those positions. Make sure you do not get too far away from those suggested values. You might miss macro nutrients being provided by a part of your fertilizer and you will run into a macro nutrient defiency. A mixing ratio suggest by the manufactor might advice you to use your 3 parts at a raio of [ 2 : 2 : 1 ]. With the Nutrient Calculator though you will find out that a perfect mixing ratio would be [ 2 : 1.7 : 0.85 ].
[Adjust the mixing ratio of the fertilizer parts that they match with the plants requirements]
Setting up the reservoir facts
In addition to the size of your reservoir you need to know about your water quality. One of the most important values is the concentration of salts in solution indicated by the electric conductivity (EC). Your plant “works perfectly” at a specific EC. Is the EC too high or too low the plant won’t work properly.
[Setup reservoir size, initial EC and target EC]
The initial EC
The initial EC describes the Quality of your base water. Unless you are using any auto PH setup such as the PH-Perfect© products by Advaned-Nutrients© or a perfectph© device by TORUS-Hydro you need to think about buffering your nutrient solutions PH by using PH(+) and PH(-) products. Take under consideration that PH modifiers alter the EC!
Either you do your PH adjustment after adding the nutrients. or you prepare a ready buffered solution which is stabelized at the desired PH. Either way – you need to know about the effects of your PH products on the EC.
There are many boosters and supplements on the market and some are containing salt which influences the EC. Cal-Mag products are a good example as they are commonly used in combination with r/o water.
Many growers suggest to adding all non N-P-K components upfront to the water. If you do so it is easy to get the initial EC. The EC of your base solution can be put into the corresponing field in the “reservoir facts” section.
About the desired EC
One of the core values of a successful grow project is to properly hit the right concentration of the nutrient solution. The needed concentartion basically depends on three main factors:
- Which size has the plant?
- Of what kind is this plant?
- What phase of its life cycle is the plant currently in?
[12 week sample EC curve indicating the “strength” of the solution in µS]
Result
In the result table you will finally see the perfect mixing ratio for all of your fertilizer parts for each phase of the lifecycle.
[The Result is showing the “recipe” for mixing the reservoir]