Fox Farm Grow Big - To feed or not to feed? [PICS]

Discussion in 'Marijuana Plant Problems' started by Fudgepackers, Jan 10, 2018.


    Fudgepackers New Member

    TL;DR? PICS BELOW. Although I highly recommend you read the background information first.

    Hi guys
    I flushed my soil about 2 days ago as my 2.5week old plant was suffering from nitrogen toxicity. Since then the tip burn has not been getting any worse but the lower leaves still look pretty dark to me.
    There was a potassium lockout due to the toxicity which is shown very clearly on the old leaves.
    The new growth is now coming out with purple spots which is a sign of phosphorus deficiency.

    However, according to this chart, phosphorus deficiency should not be the case.
    Despite the chart, I still believe it's phosphorus deficient considering all other factors (nitrogen toxicity & potassium lockout followed by flush).

    I have with me a bottle of Fox Farm Grow Big. It is all I have currently as I am in the early veg stage of my first grow. Based on my current circumstances explained above, and the pics displayed below, would it be safe for me to feed the plant right now?
    The grow medium is bio bizz all mix which also contains added fertiliser 50L/m3. Maybe I should just water the plant?

    To put it plain and simple, I want to feed the plant with my grow liquid to remedy the very obvious phosphorus and potassium deficiency, but I do not want to cause any more nitrogen toxicity or cause another potassium lockout.

    The pic below features leaf tips that are purple as well as purple discoloration towards the base of the leaf too. Also note that the new growth is coming out pale with green veins - classic sign of nitrogen deficiency. However, refer back to the chart and you'll see nitrogen deficiency should start on old leaves first, and the old leaves are still very much a deep, lush green.
    See what I mean? My head's gonna explode

    Included a side view of the plant so you can judge for yourself whether the lower leaves look too dark for more nitrogen
    Last edited: Jan 10, 2018

    Ablaze Well-Known Member

    If it were me, I'd do two things. The first thing I would do is get them out of that soil completely. You really shouldn't have problems with soil. Just ditch it and replant in new quality soil without adding fertilizer. There will be plenty of nutrients for the plant to fix itself. A month or so later you'll need to replace the nutes it's used.

    Second. They're now also ready for a bigger container. Kill two birds with one stone and transplant out of that soil and into a bigger container.
    dtl420 likes this.

    dtl420 Well-Known Member

    What is the temp in you're grow space? The purple could be caused by cold conditions. I'm not seeing any potassium issues. Typically you'll see a lot of stretching with potassium deficiencies, along with leaf symptoms. Potassium deficiencies are pretty rare.

    You're chart is very vague. It's referring to mobile and nonmobile nutrients. Calcium, for example, is semi mobile. But in you're chart it says it shows on the new leafs when typically it shows on the middle of the plant.

    You're best bet is to do what @Ablaze said, and pot up. Get some decent dirt or learn how to make shitty dirt decent. And don't feed her till she wants it, you'll see those lower leafs start to turn a lighter shade of green when she's ready.

    Fudgepackers New Member

    Temp is 23-25 celsius.

    Fed her with fox farm grow big 1&1/2 tsp to the gallon, purple patches started getting lighter. Will repot soon

Share This Page