NPK requirements with Organic Growing

ozgirl

Active Member
Hi, I have a question about the NPK requirments for a plant throughout growth, and the best way to achieve it organicly.
I am making my own compost, and have plenty of chicken and horse poo on hand any time,(which im not using on the plant) and have currently been feeding with charlie carp which has a NPK of 9-2-6, and am in the second week of flowering.

Im also confused on how often to add the fertiliser, the instuctions say every 2 to 3 weeks, however I have read so often people saying they feed nutrients every 2nd day or so, am I underfeeding?
 

Gastanker

Well-Known Member
If you top fed the soil then you are probably good to stop feeding that fertilizer and start focusing on something with less nitrogen. kelp meal has a high K value and you can use a high P bone meal or bat guano as well. All three can be top fed (blended into the soil) and the kelp meal and bat guano can also be made into a tea.

When people talk about feeding every other day it is usually with a tea - essentially mixing the kelp meal and bat guano with water and then watering the plant.

With organics you need to keep in mind what is immediately released to the plant and what needs to be ionized beforehand. Bone meals are slow release and thus only need to be administered once ot twice. Most bat guanos are 50% slow release and 50% immediate release and kelps are similar.
 

Mother's Finest

Well-Known Member
It's not every other day, it's every other watering, or at least in the opinion of some it should be. Fertilizations are usually best alternated with plain waterings. It helps prevent the constant buildup of crap from fertilizing every time, washing soon to be degrading nutrients both into the plant and out the bottom.

The primary flowering nutrient for most types of cannabis is Potassium and the secondary flowering nute is Phosphorus. Some strains will use equal amounts of both. The amunt of Nitrogen needed in flowering depends on how leafy the plant & buds are. Since N promotes leaf growth and leaves are harsh to smoke, the plants only get as much N as they need to avoid N def. Different types of plant will have different nutritional requirements, but a good average ratio (arguably) for flowering would be around 4-5-6. Less N is often given to the plants towards the end of flowering.

It's close to backwards for vegging, with a good vegging ratio being about 6-5-4. Vegging plants will also get much less fertilizer and that veg ratio will be used at a lower concentration than the flowering one. To find the best concentration for your strain at a given size, you just increase the solution strength at each feeding and watch the lowest and oldest leaves on the plants. The pod leaves, the first single-bladed leaves and the first three-bladed leaves usually show nutrient burn first, in that order.

The best fertilizer regimen for flowering, when you give the plants all they can handle, will burn off at least the single-bladed leaves. If at least those don't get burnt to a crisp, you could have fed the plants more and subsequently harvested more. How much this takes depends on the strain & how big it gets, as well as on how much light the plants receive. The more light the plants get, the more food they need to go with it.
 

ozgirl

Active Member
Thanks very much for the response both mothers finest and gastanker. Obviously my 9-2-6 is not good for flowering, would adding some kelp and bonemeal now be enough to compensate, or would it be better to find another fertiliser with a more suitable NPK.
I wish my compost was ready to use so I could have some compost tea on the go, but it will be about 6 weeks or so yet.
 

Mother's Finest

Well-Known Member
Well first you should keep in mind that while a 9-2-6 fertilizer isn't perfect for flowering by itself, it can certainly be used in conjunction with other ferts. Between that, the Bone Meal and the Kelp, you should have good sources of N, P, Ca, Mg, Fe and others. You don't seem to have a high-K fertilizer and Potassium is usually the primary flowering nutrient. This is the best source of K we know of http://www.planetnatural.com/site/organic-potash.html
 

ozgirl

Active Member
That potash looks like good stuff, maybe that combined with bonemeal will be a great choice to boost my budding. Also I have found this product would you, or others mind having a look for me, it has a complete analysis on it, and has a npk of 8-8-9 and organic, im thinking it would be a great feed from start to finish, with maybe also a little bonemeal and potash??

http://www.nutri-tech.com.au/downloads/product_information_sheets/Life-Force Home Range/Life-Force Total Cover with Selenium.pdf
 

Mother's Finest

Well-Known Member
We haven't seen that before and since it doesn't list what it's made of, we can't say anything about it. Nothing jumps out as being unhealthy for the plants, though. Even the pH looks kosher.
 
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