Looks like a crisp and efficient grow Boradan, your ladies are stunners. Crazily enough, I’m feeding my girls the minimum 4 gr/gal recommended MC dose and it seems to be more than enough. I’m not brave enough to really drop it, still a bit too green. Also not in a big rush to start Bud Explosion — I just flipped to 12/12 and don’t have buds yet, plus MC is supposed to contain bloom nutes. Running at about 900 ppm which is lower for me. I wonder if the Heisenberg tea possibly lets them make better use of the nutes they have? I wouldn’t be surprised. I’m going with the less is more mantra on this run and see where it takes me...
No need not to 'be brave'.
Remember that guidelines from the Nutrient supplier are exactly that - guidelines.
Different strains, and indeed, different plants from the same strain will have different needs unless they are clones.
Even Greenleaf's own instructions emphasise that.
https://greenleafnutrients.com/feeding-calculator/?v=d2cb7bbc0d23
- Pay close attention to the green coloring of your plants leaves. Nitrogen levels in MEGA CROP are strongly related to how green your plants leaves will appear
- If your plant leaves are light green or yellow, then increase your dosage of MEGA CROP to boost Nitrogen levels and increase green color
- If your plant leaves are too dark green and/or have burned tips, then scale back your MEGA CROP dosage to reduce the nitrogen.
- Your goal is to have the plants coloring to be a strong healthy green without burning, and you control this by increasing or decreasing the MEGA CROP dosage. If you are a new grower and not sure what color your plants should be at, browse the internet for pictures of healthy plants of your same type. You should make dosage changes for the first time in small amounts, for example changes of 10-20% increase or decrease only, and then waiting 2-3 weeks to monitor plant response after each change. Since the plant has to take time to uptake nutrients and process them, it may take 2-3 weeks to notice the results of the changes you made.
**NOTE DWC plants respond to changes a lot quicker than soil-grown plants.
I also agree 100% with the Tea aiding in the nutrient uptake. They increase the efficiency of the roots and make a little go a long way.
My experience is that MC 1.0 @ 500 ppm (~ 4 g/Gal) causes nute burn in DWC when following the VPD chart.
I now believe 400 ppm is closer to optimal, and I've never had a plant for which 400 ppm is too little.
I'd guess that making a chart of grams MC per Gal graphed horizontally vs. amount of healthy growth graphed vertically is a bell shaped curve, with the optimal amount of feed as its peak.
I'd further guess that that optimal peak is passed long before ultra green leaves plus yellow leaf tips happen.
If that's true, then waiting for yellow leaf tips to indicate overfeeding is like shutting the barn door after the horse has escaped.
For example, if yellow leaf tips start at 500 ppm, that doesn't imply that something slightly less than 500 ppm is the optimal amount.
What might have happened is that optimal was 400, growth slows with ppm 400-500, and noticeable harm happens at 500 ppm.
In this extreme, made up example, a plant grown with 400 ppm would likely yield more than a plant grown with slightly less than 500 ppm.
Users of pH Dn should remember that it contains phosphoric acid, which probably supplies all the extra P plants might need during flower.
Greenleaf tells us that only MC is needed.
I believe them.
I am doing this grow following the VPD guidelines.
I agree 100% regarding the nute burn and the bell-curve.
Whilst Greenleaf have stated that only MC is needed, they also offer advice on dialling in Bud Explosion too.
As all plants are different, there is never
really going to be a perfect one-size-fits-all single nutrient. MC will get you damned close, but it can still be modified/boosted with judicious use of a PK booster.
I ran my previous grow using only Megacrop and Calmag (necessary under a COB).
There were issues with some plants being fine and others having N-Tox or calmag problems, showing just how hard it can be to create that perfect all-in-one mix.
(*** In no way is this a slight against MegaCrop, it is just how it is in the real world. I had no way to dial in MC for each plant individually as it was a 4-container RDWC system, so I had to compromise. This was an issue with my system and NOT with Megacrop***)
This current grow is running at 270ppm for the BCN Critical XXL and 320ppm for the Critical+ 2.0 using the ppm500 scale (so 0.54EC and 0.64EC respectively) - there is also 190ppm from the tap water I use in addition to those readings.
