Could be. It may be pH related as well since we are bare root, Mg is generally more available at higher pH
I would suggest picking a mix and running it in your setup. Then working from there. Once you start balancing K, a diffusion ion to Ca and Mg, mass flow ions, your environment becomes a significant factor. For instance Iām in a low desert greenhouse and the PLC picks different feeds based on avg temp, vpd and light intensity. To put it simply, the lower the transpiration, the less K you will need. The one thing you can pretty easily watch is if Ca is in sufficiency range using a refracrometer. The other thing you can do is foliar feeds of individual salts and record if they increase your brix. If a salt increases brix, bump it up in your mix and repeat.
You, I or anyone else canāt make a perfect mix for your distinct environment and style without running something and generating some data, may that be refractometer or tissue analysis or sap analysis. I have a client that has different lead growers in charge of different flower zones in the same building and every single one has slightly different feed.
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Fair enough. I will run the mix I have and take it from there. I will be ordering a refractometer this week. Thanks to everyone for pointing me in the right direction.
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Hello everyone. So Iāve been running a mix now for almost 2 weeks, and am experiencing a Mg deficiency. Iāve been mixing my own salts with the following profile.
N-143
P- 66
K- 238
Ca- 182
Mg- 91
S-178
Si- 18.2
Fe- 3.7
B- 0.68
Mn- 1.05
Mo- 0.03
Zn- 0.2
Cu- 0.05
Anybody see anything wrong with this profile? Iām in coco DTW. Cob L.E.D. Daytime temps at 82. Rh 55.
Night temps 75. Rh 50. 1.3 ec going in. Runoff testing at 1.6 ec. Ph of feed at 6.1. Runoff ph testing at 5.8. Let me also add that the plants are still in veg.
I would like to correct this through adjusting the salt ratio if possible, not a Folier spray. I will go the spray route if all else fails with the salts. I did try raising the ec for a few days, and things looked worse than before. Anyone have any suggestions? Open to all advice and, critiques. I will not stop till I master salts lol!
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That humidity is pretty low if youāre in veg. Gotta make it swampy and get the vpd in order. Are you running co2 with leds? Just my 2 cents
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No co2 at the moment.
How long have they been in that medium? Was another nutrient profile used with that medium before this one? The mix you have is almost all nitrate, should be a rising ph mix, not falling, thatās why I ask.
Thatās not a simple Mg deficiency. See how narrow and light in color your new growth is and that the interveinal chlorosis is starting as the leaflets start to expand? That implies immobile elements and you have to remember that Ca is the trucker of all those immobiles and is the king of transpiration. The more transpiration you achieve the more mass flow immobiles you can absorbā¦ What is the watering schedule like? If they are constantly wet a Ca issue will be exacerbated. In the short term I would drop the SOP to a point that K is roughly equal to Ca to ājump startā transpiration by allowing more Ca to be absorbed. Doing so is going to change your N:K ratio and will probably cause your leafs to go down to 3-5 prong. Once you get healthy colored new growth going you can slowly work the SOP back up.
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Thanks @emdub27. Was hoping you would reply. They are in fresh, charged, and buffered, 70/30 coco/perilite. I water/feed once a day, but might have to increase to twice a day, because they have been slightly wilted come watering time. I initially thought I had lockout due to salt build up from letting the coco dry to much, but run off Ec was not very high when I did water them. They are 1 gallon plastic pots.
Wanted to add that the plants look better a few hours after theyāre dark period, when the lights come back on, and have been on for an hour or two, but are back to looking like shit about an hour or two before lights out. I will get to work on a mix with closer to equal parts K - Ca.
Charged and buffered with what? Something is pulling the ph down, you should be seeing a .3ph rise not fall.
Temporarily dimming the lights can also help them get out of this. Right now there is more light than they can use.
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Not sure what it is buffered with, but I do know it is charged with Ca carbonate. I was told this would fill cations so the coir doesnāt use up the Ca I add to the feed.
It is a new brand of coir I have been using the past few runs, to see if it compares to the CYCO coco coir I usually use. Fox farms Coco Nation 70/30 perilite blend. It is much cheaper than the CYCO.
Hello @emdub27. I wanted to ask you, would you suggest upping the elemental ppm of the Ca, or keeping it at 180 ppm, and just bringing the K down closer to the Ca? I was thinking of upping the elemental ppm of the Mg to 100, and bumping up the Ca to 200, and bringing the K closer to 200 ppm. What are your thoughts?
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Leave the Ca and Mg where they are. Just dropping the K by the roughly 60ppm will profoundly change how the other cations are absorbed.
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Honestly it looks like you may have some root health problems and that can cause all sorts of nutrient issues to manifest. Especially Ca in my experience. Itāll be hard to evaluate the feeding if the roots arenāt happy and based on how the plant is droopy that would be my first guess
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Thanks for the advice.
They seem to start doing that about 2 hours before lights out. When the lights come back on, they are fairly perky. Iāll snap a few pics when Iām home.
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One thing I wanted to ask you was, what Ec would you recommend starting at? I usually start around 1.1, and go by what the runoff tells. Would you suggest starting higher?
Pretty much 2.0-2.4ec all the time for us from clone on.
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