Phosphorus Question

Discussion in 'Growing Organic Marijuana' started by Killarado42o, Aug 10, 2011.

  1. I was wondering what would be the best organic source of phosphorus for my girls? They just started flowering 4days ago and already show pistils and everything. Im kinda strapped for cash, so i wanted to use my veg fertilizer which is Bio-Grow 1-0-6 and maybe mix in something with a good amount of phosphorus? I was thinking maybe i could get some bone meal and somehow mix it in with water/veg fert/bone meal?

    Any help would be great :smoke:
  2. What do you have in your soil? Bone meal takes quite a while to break down and makes a better soil amendment than a top dress. If you are using a store bought soil chances are you might have P covered. And as you probably know, you don't need much P. Fish hydroslate is one that could help and would work fairly fast. MIW
  3. In addition to Bone meal, high-P Guanos are also some of the best sources of Phosphorus. Both need to be made into a tea for manual fertilizations and both have extra benefits when mixed into the soil. Bone Meal teas should be made with heat because BM doesn't dissolve well in cold water.
  4. MI Wolverine- Im using FF Ocean Forest, I thought you wanted a higher number of P for flowering? Im sure the soil has enough to sustain plant growth, but if i can somehow help the plant flower better why not? :smoke: Thanks for the advice of the fish hydroslate.

    Jellyman-I think thats what im gonna do, Do you think i should mix in some of my veg fert? I think if i start with a very low dosage and slowy move up i can find a right balance without harming my girls:D

    Thanks guys
  5. Killar, I don't think the FFOF could bring you through flower with what it has in it. That's why Fox Farms sells all their chemicals - they want you to buy that in addition to their amended, top dollar soil. What comes in the soil is weak at best, so if you are going to try to go through flower, be prepared to top dress with amendments/minerals (guanos, EWC, fish hydrolysate, Seaweed Fertilizer, Excellent compost, Sul PoMag, Cal Mag, etc) and pour on some teas and build an AACT to supplement that soil. Just some thoughts. Good luck with your grow and get us some pictures as things progress.

  6. Killorado420 you may want to google the myth of high P It seems current research shows our plants do not need a lot of P.......MIW
  7. Fish Bone Meal is a good source of P. As well as Soft Rock Phosphate
    The thing about P is that it is very difficult for the plant to get. Most of it remains unavailable. That is one of the reasons having a mycorrhizal relationship is so beneficial. The fungus will bring the P to the plant.
  8. However much P the plants need, Phosphorus deficiency is the most common deficiency in the pot growing world, for both vegging and flowering plants. I like to suggest roughly equal amounts of P & K during flowering.

    You can add your vegging fertilizer in early flowering but watch the Nitrogen. It depends how leafy the buds are (e.g. indicas often use more N in flowering), but too much N during flowering can quickly cause N toxicity & Nitrogen claw. You'll want to start flowering using a little less N than you used in veg and that amount is slowly decreased as flowering progresses. Most grows do well cutting out all N from feedings by 2/3 of the way through flowering.
  9. Jellyman, the problems you are describing are why I feel a high quality humus component, and humic acid are important. Add high quality thermo compost and or high end ewc and the odd tea here and there and you won't have to fix anything.....MIW

  10. Case in point is soft rock phosphate widely recommend as a viable source for Phosphorus.

    Reading the label indicates that it's a far better source of Calcium (23%) than Phosphorus: Phosphorus is 23% and Available Phosphorus is 2.3%

    Crab meal has 2.1% Phosphorus. Limestone has 2% Phosphorus and the same with Oyster Shell Powder (from Pacific Pearl in San Francisco)

    Even neem & karanja meal are better sources of Phosphorus than soft rock phosphate.

  11. This is the best advice presented IMO. Soil organic matter (SOM), aka 'humus' is the best available source of P you can add to your soil grow. P is a difficult element for a plant to obtain and its availability is impacted and conflicted by many, many factors; pH, Al, Fe, soil compaction, areation, cold soil temperature, soil tilth or texture (CEC), chemcial reaction with other elements, and a few other factors. It is taken up by the plant root almost entirely in the primary or secondary orthophosphate form, anion (-) charge. This is where the high CEC factor (usually high SOM) comes into play because the cation (+) will help hold the anion thus making in "available" if it is in the correct elemental form (orthophosphate).

    Short answer, more SOM in the soil mix and an active and hungry microherd, good soil tilth, good areation, in the zone of the right temperature.

    P is one of the most studied plant required essentials and like the nitrification cycle it too has it's own - "The Phosphorus Cycle". It has to be in the right elemental form or the plant root can not absorb it.
  12. Great post Possuum, as you point out making P available, is wiser than pouring more P on. Once your soil mix is right, things just roll ......MIW

  13. Once it is right .........

    The problem here is that the OP is in flower and the nutes he's been using are 1-0-6, so no P at all.

    I add my P sources when I make the mix since they take so long to break down and I take that into account. If I do have to do a top dress, I usually figure on a month-6weeks before it's available. I'll put bone meal on my wifes Iris plants in the fall for the following spring.

    I've never used guano, since I can's source it locally. Funny thing is, there are plenty of old 100lb+ guano bags around from tobacco growing.

    I'm just wondering if a high P guano might be his best bet? I just can't see bone meal, even in a tea, being available anywhere near soon enough. Same deal with the rock phosphate.

    Would a high P guano tea be the fastest? IDK, but I am curious.

  14. possuum- Thanks for the scientific break down,lol but since im so far along would just adding a top layer of humus to my soil help? since i cant mix it with my soil?

    wetdog- I think that might be a good idea, i want to make some kind of tea since i already have veg nutrients that i can mix in. This is only gonna be for a few weeks at most, but i still have 8 weeks ahead to get things right.

    So what does everyone think about the guano tea? In addtion to my current veg fertilizer?
  15. if you've just started flowering a balanced npk is OK, like dr earth 4-4-4 or what not.

    If you're using the guano tea, it should get your plants the P they need, but careful not to burn... the guano is absorbed slowly, so you won't see the results you are looking for within a few days (like some liquid nutrients), don't despair and add more guano... if you want to hit your plants with a guano tea 1 tsp per gallon should be a hot dose. top dressing with earthworm castings, humus, or molasses is 1idea at this point. just don't over-do it.
  16. I'm walking out to the edge of the plank and staring into the abyss. I know this. But here goes.

    First, these three are fairly easy reads (“easy” is relative because there is nothing easy when it comes to understanding phosphorus/phosphate).

    Understanding Phosphorus Fertilizers

    The Nature of Phosphorous in Soils

    Soil Management

    Now take that combined information forward with you and read this keeping in mind the way phosphorus reacts with other elements and what it actually does in the soil when it comes in contact with water


    Now you should have a better understanding of what P actually is along with the many potential forms of P available to you.

    This is an interesting study and analysis on several products we are all familiar with. And again, we're still discussing P

    Analysis of Organic Fertilizers

    Keeping in mind that you want an “organic solution” even though we've now got a better understanding that “P” isn't generally considered organic though it is often derived from organic sources (plants, animals, and manures), if you are looking for that “organic shot” a high P guano with no N might be your best solution (you didn't ask about N so I assume you have that covered). I can't say for certain that a P guano is your best bet because when discussing P, it is definitely not a one-step, one size fits all solution. There are too many other individual and collective factors to consider for your particular needs and since you are the closest to your grow you're gonna have to make that call.

    Hope this helps a little bit. Phosphorus inputs are many but each has its rightful place based on a host of other considerations. Good luck and I hope you get what you need out of the above.
  17. id recommend "budswel" it consist of bat n seabird guano with earthworm castings, has an npk of 0-7-0. its all organic and wont burn your plants. i know you said youre strapped for cash but im sure you can come up with 20 30 bucks.

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