Growing in coco, EC, Canna a & b

[Marmaloid]

Hi all,

What would be your advise.
I'm 4th week of veg, EC output has never risen. I've upped my feed to input ec 2.0 way higher than canna feed chart recommendations. Ec out is consistently 0.6. Feeding once a day. Not had nutrient burn but as I'm feeding higher than what canna recommend I'm unsure what best.
Every few wks from clones I get the start of a calcium deficiency. Different environments so I'm not sure it's that. Had to foliar feed. I'm just concerned when I flip. I can't really foliar feed. Water ec. 3 brought upto. 4 with calmag agent which is what canna recommend. Temps around 25c, relative humidity around 65. Plants look fine, I'm just wondering why the ec isn't following the general concensus of input and output being close. Also stems of leaves and main stalk look pinkish red. Read it could be genetic. What are your thoughts on that. Strain is incredible bulk. Cheers

 

[ArtfulCodger]

Manufacturer feeding charts are a general guideline at best. They're OK for mix ratios, but pretty useless for amount. Canna doesn't know your plant size, plant health, pot size, shot size, light level, or your watering frequency. If your runoff EC is holding steady, you have good growth, and you're not seeing deficiency symptoms, you're in the ballpark of where you want to be.

 

[Marmaloid]

Manufacturer feeding charts are a general guideline at best. They're OK for mix ratios, but pretty useless for amount. Canna doesn't know your plant size, plant health, pot size, shot size, light level, or your watering frequency. If your runoff EC is holding steady, you have good growth, and you're not seeing deficiency symptoms, you're in the ballpark of where you want to be.

So I do have a deficiency. Top of plant. Looks like mag to me but in the wrong place according to the Internet. Cal mag it and goes away. Up feed. Two weeks later it's back. Any thoughts please.

 

[ArtfulCodger]

The first thing I'd do, if that were my plant, is turn down and/or raise the light. Mg is the central atom in a chlorophyll molecule, so demand for it is driven by light level. You can see the edge curl and taco-ing on your tops...they're contorting so they don't have to process so much light. Both the interveinal yellowing and the purple stems and petioles are indications that the light is outrunning the available Mg. You can also increase the amount of Mg in your feeding, but keep an eye on runoff EC/ppms so you don't get locked out.

 

[Marmaloid]

Thank you for that. This light is a beast. I had already took the light up as far as it will go. What do you run your ppf in late veg. Currently at 595 umols as advised by someone else. Thanks.

 

[Marmaloid]

If I'm feeding canna a and b and want to add extra magnesium what would be your recommendation for that. I have a mono magnesium and says on bottle 1ml per litre. Does it all depend on output ec rise. I'm so low on output at minute don't think it matters what I add until run off starts to increase. Thanks.

 

[ArtfulCodger]

Thank you for that. This light is a beast. I had already took the light up as far as it will go. What do you run your ppf in late veg. Currently at 595 umols as advised by someone else. Thanks.

I run my lights at the level that my plants show me that they like. It varies pretty widely by cultivar, and even by pheno among sisters grown from seed. 600 umols is more than I ever run in veg, in coco with ambient CO2. In the last week of veg, I'm usually around half of what I expect my final flowering intensity to be.

Tough to say about Mg supplementation, without knowing more about your feeding and how much is already in the pots. I aim for around 50 ppms of Mg in late veg, but will adjust based on what I see. Like I said, the first thing I'd do with your plants is turn down the light to take my foot off the accelerator.

 

[Marmaloid]

Thank you for the info. Will really help. Your a star.

 

[Marmaloid]

I run my lights at the level that my plants show me that they like. It varies pretty widely by cultivar, and even by pheno among sisters grown from seed. 600 umols is more than I ever run in veg, in coco with ambient CO2. In the last week of veg, I'm usually around half of what I expect my final flowering intensity to be.

Tough to say about Mg supplementation, without knowing more about your feeding and how much is already in the pots. I aim for around 50 ppms of Mg in late veg, but will adjust based on what I see. Like I said, the first thing I'd do with your plants is turn down the light to take my foot off the accelerator.

Hi there. Nearly at 3rd wk of flower. Plants look fantastic after following your advise. So thank you. Just unsure how to turn my light up now. I've tried a few times and get leaf curl. When will I know it's time to turn the light up. At moment it's 425 umols. Thanks.

 

[ArtfulCodger]

Hi there. Nearly at 3rd wk of flower. Plants look fantastic after following your advise. So thank you. Just unsure how to turn my light up now. I've tried a few times and get leaf curl. When will I know it's time to turn the light up. At moment it's 425 umols. Thanks.

I turn my light up when my plants look healthy, and they're still praying an hour before lights-out. How big is your tent/space? How many watts is your light? How high is the light hanging above the tops? Keep in mind that our goal is healthy flowers, not a particular light level.

 

[Marmaloid]

Thank you for your reply. That's the sound advice I was looking for to be honest. So I'll bear all that in mind.