Question regarding Ca uptake in early flower and VPD

[ButterflyEffect]

i like this chart easy to read. obviously 20 percent is very low desert style. but imo the best environment is the one gives you results ya like so do you if its goin well. also important to remember its leaf surface temp not ambient to measure. it does make a difference

https://www.dimluxlighting.com/knowledge/blog/vapor-pressure-deficit-the-ultimate-guide-to-vpd/

That's the chart I've been going by. I've been trying to incorporate the formulas into my controllers' code, but I gave up. I have different 4 different programs that I run during flower and it's close enough that trying to get the numbers tighter would be a diminishing returns situation.

Basically, it's Stretch(80F/70H), Mid-Flower(80F60H), Early Ripen(78F/50H), Late Ripen(76F/40H)

 

[ButterflyEffect]

The AC Infinity fans with the Bluetooth Controller 67 will display the current temp, humidity and VPD. You can target temp or humidity but not the VDP. And it has a app.

During the winter here I use a small heater at first when the lights come on to boost the temp up to where it will stay on it's own from the lights. But you have to let it heat up then turn on the humidity control, I limit it to 80% during this time. Takes about an hour with room temps around 65F and tent temps stabilizing at 75F. Then target the VPD. The humidity will rise up into the 70% range.

It also has a humidity offset that will increase the fan speed 1 point (0-10) per 1 % rise if you want. This is good if you get big or rapid swings in humidity. And it has a leaf temp offset too you can pick at 2F. If you get one consider the next size up that what you think you need. It will be quieter.

The fan seldom runs at more that 3 out of 10. But it you are pushing it a long way or though many bends or a filter the bigger size will be appreciated.

In the small tent I'm also experimenting with a small piezo electric dehumidifier when the lights are off. It's 40 watts and keeps it under 70% but not anywhere near the ideal VDP when the lights are off.

I have 3 rooms, so it gets to be a bear to control all of them. That's why I decided to run them all with arduino controllers and 30A power relays. This was the A/C, Heat, Dehuey and the mister are all called for when needed with no intervention. The only things not connected to it are the extractor fan(timer) and the lights(also timers). I'm in the process of upgrading them to wireless so I can monitor the rooms, produce graphs and manipulate equipment remotely. At the same time, I'm going to try to implement night time programs into them. The controllers don't have clocks so I have a photo eye diode that simply 'sees' whether the room has light or not and runs the corresponding program.

 

[ButterflyEffect]

yea i have an ac infinity product fan as well. i like them although the interface could be easier. the cool thing about that vpd page is theres a calculator function which allows you to change the ambient/leaf surface temp offset. with range from 0 to 5 degrees between the leaf and the air those leaf temps make a significant difference in your target humidity. but you do need one of those gun temperature meters like used for bho etc. dimlux has lots of good info

I use one of those little IR temp meters. Oddly enough, my leaf temp is never more than 2 degrees F higher than ambient.

 

[Three Berries]

I use the CaCl2 at 500ppm per gallon for the nute mix in well water, about two tbls of liquid, some 1200 ppm for top dressing the soil in rain water and at 500 ppm in a foliar rain water spray, with MgCl2 and glycerin . They say spray near the end of the light cycle so not the best for flower, but I spray when the lights are on too so...

 

[Three Berries]

I still have some Calcium Acetate around too. This also is water soluble and the Ca is immediately available. it breaks down to Ca and Acetate (vinegar) though. Would be most excellent for using with hard water as the acetate would react with the carbonate and make CO2 neutralizing the Acetate and Carbonate. Not for foliar feeding though.

 

[ButterflyEffect]

I use the CaCl2 at 500ppm per gallon for the nute mix in well water, about two tbls of liquid, some 1200 ppm for top dressing the soil in rain water and at 500 ppm in a foliar rain water spray, with MgCl2 and glycerin . They say spray near the end of the light cycle so not the best for flower, but I spray when the lights are on too so...

I'll be honest, I'm intrigued by a Ca foliar that actually works. So much of what I've read and been told is that they simply don't work. It must be something with the Chloride. If I use it in flower it would only be in the first 2 weeks anyhow.

 

[ButterflyEffect]

I still have some Calcium Acetate around too. This also is water soluble and the Ca is immediately available. it breaks down to Ca and Acetate (vinegar) though. Would be most excellent for using with hard water as the acetate would react with the carbonate and make CO2 neutralizing the Acetate and Carbonate. Not for foliar feeding though.

I might consider using that for my veggies as I feed water them with the well water and it's fairly hard. Good to know about this. Thanks.

 

[Three Berries]

I might consider using that for my veggies as I feed water them with the well water and it's fairly hard. Good to know about this. Thanks.

When adding the acetate or vinegar to high pH hard water it immediately frees up the Ca and Mg just like the chloride does and lowers the pH, CO2 is the waste.

 

[ButterflyEffect]

When adding the acetate or vinegar to high pH hard water it immediately frees up the Ca and Mg just like the chloride does and lowers the pH, CO2 is the waste.

Oddly, my hard well water has low pH. Around 5.8-6. Aside from the hardness, which IIRC is around 75, it is high in sodium and Manganese. It's a shitbrew of just terrible water.

 

[Three Berries]

Oddly, my hard well water has low pH. Around 5.8-6. Aside from the hardness, which IIRC is around 75, it is high in sodium and Manganese. It's a shitbrew of just terrible water.

If the sodium and manganese are carbonate form then you would NOT want to use the acetate unless you want those two minerals freed up. Low pH water though would eat up the carbonates I would think. You around hard rock? I'm blessed with a deep aquifer right underneath me that filters though limestone.

 

[Piff_cat]

This right here is why I;m struggling with the justification to go LED. I'm using CMHs, so to get to the same PPFD, the LEDs would use close to the same energy. I'd be likely using less A/C, but a heater is 1500W compared to around 600 for the A/C. Then you have the price for admission, and that'd be close to $1000 per room. Yikes!

I depend on my 3 rooms always producing so that would be a critical error to make at this time. If I get to a point with excess stock that I can retrofit my 3rd room, I'll certainly consider it.

the best solution ive come up with for my growing priorities is using a low wattage single ended hps in tandem with the led. this is not cost effective but does provide both the neccesary ir heat, the extra red spectrum needed for flower production, and the high ppfd of led. the way i see it if im using a heater i might as well get some lumens out of it. and the single ended hps is basically free these days. fire weed was grown with single ended hps for decades so we know it can produce quality. the led is unquestionably more efficient considering electric draw and the lower cooling cost. but if you look at transcription levels for cannabinoid genes drought and diurnal temp difference always have the highest up rates. once again somewhat strain dependent, but everything we want out of the plant comes from a stress reaction. whether it be uv, herbivore protection etc safe plants are low potency plants compared to stressed. stems and leaves will thrive but were not growing leaves lol

 

[Three Berries]

I forgot to mention or think about the fact in winter here my CO2 level is usually 2000-2500ppm and can go higher for periods depending on how cold it is outside and lack of wind.

This made my Ca problem worse I'm sure.

 

[Piff_cat]

you mean 200 250 ppm?

 

[ButterflyEffect]

If the sodium and manganese are carbonate form then you would NOT want to use the acetate unless you want those two minerals freed up. Low pH water though would eat up the carbonates I would think. You around hard rock? I'm blessed with a deep aquifer right underneath me that filters though limestone.

I'm looking at my water report but it doesn't say whether the sodium or the Mn are in carbonate form. There is a lot of hard rock but I've been told it's due to the hill our road is on and the shit they put down to salt the roads in the winter. When I lived on the other side of town I had city water and never had any issues. This is why I started collecting and using rain water, I just recently realized the need to buffer it which is why I began adding that percentage of well water to the tanks.

 

[ButterflyEffect]

the best solution ive come up with for my growing priorities is using a low wattage single ended hps in tandem with the led. this is not cost effective but does provide both the neccesary ir heat, the extra red spectrum needed for flower production, and the high ppfd of led. the way i see it if im using a heater i might as well get some lumens out of it. and the single ended hps is basically free these days. fire weed was grown with single ended hps for decades so we know it can produce quality. the led is unquestionably more efficient considering electric draw and the lower cooling cost. but if you look at transcription levels for cannabinoid genes drought and diurnal temp difference always have the highest up rates. once again somewhat strain dependent, but everything we want out of the plant comes from a stress reaction. whether it be uv, herbivore protection etc safe plants are low potency plants compared to stressed. stems and leaves will thrive but were not growing leaves lol

Very good points there Piff. I'm likely gonna stick with the CMHs for now since I get the best of both worlds for now. To be honest, one of my main motivators for going LED would be the abiulity to go back to growing horizontally instead of vertically. I do vertical because I simply don't have enough amperage going to the grow to support 3 flower rooms and a veg room and get the light spread I need. Vertical allows me to achieve that but it comes at the expense of screening the plants, which is very time intensive.

 

[ButterflyEffect]

I forgot to mention or think about the fact in winter here my CO2 level is usually 2000-2500ppm and can go higher for periods depending on how cold it is outside and lack of wind.

This made my Ca problem worse I'm sure.

Christ! I'd love to have those CO2 numbers!! I did surveys on my rooms and I average 4-500ppm during lights on. My temps are already at ~80F so I keep the feed at 1000ppm or less and the humidity is precisely why I started this thread.

 

[Three Berries]

you mean 200 250 ppm?

No. I have an open flame heater and use constant ventilation in the winter. The colder it gets the higher it is. I have a variable house exhaust and keep the level under 3k when I can. It seems to accumulate in the tents. The flower tent is part of the whole house ventilation but has a parallel fan to bypass it.

Even in summer with the central AC on the CO2 can be near 1000 due to a tight house. The wind is the biggest factor.

 

[Three Berries]

Christ! I'd love to have those CO2 numbers!! I did surveys on my rooms and I average 4-500ppm during lights on. My temps are already at ~80F so I keep the feed at 1000ppm or less and the humidity is precisely why I started this thread.

I use Langbeinite in the soil for added KSO and MgSO. But have a solution made up of 1200 ppm CaCl2, 100 ppm, MgCl2 and some KOH to pH as I'm using rain water. I have been giving all some but the biggest plant is taking it twice a week, 1/2 cup and looks to be heading for 3 times a week. This is on top of the nute mix I give them with 600 ppm or so Ca.

My struggles of the last 5 years are starting to make sense now.

 

[Piff_cat]

No. I have an open flame heater and use constant ventilation in the winter. The colder it gets the higher it is. I have a variable house exhaust and keep the level under 3k when I can. It seems to accumulate in the tents. The flower tent is part of the whole house ventilation but has a parallel fan to bypass it.

Even in summer with the central AC on the CO2 can be near 1000 due to a tight house. The wind is the biggest factor.

oh i understand i actually really like that idea and are planning on doing something similar. co2 has always been preached with a sealed environment and maybe that is best for injection. however i see no reason not to use a burner with open ventilation if all your losing is burnt propane. i personally believe there are unforeseen consequences of a sealed environment especially for cannabis. we do not yet know all of the factors which lead to secondary metabolite build up and i also think oxygen level and nitrogen fixing can come in to play. my plan for a larger room is to simulate high altitude by depleting oxygen. and i think the best way to do that is by using a burner since it will also add co2, infrared heat, and humidity as well. the dimlux 400v de 1000w hps have an active extraction port and also have a self dimming capability with a leaf surface temp thermometer. you set the surface temp and the light will dim if it reaches too high. it will take some dialing in but i think this could lead to some great results.

 

[Three Berries]

oh i understand i actually really like that idea and are planning on doing something similar. co2 has always been preached with a sealed environment and maybe that is best for injection. however i see no reason not to use a burner with open ventilation if all your losing is burnt propane. i personally believe there are unforeseen consequences of a sealed environment especially for cannabis. we do not yet know all of the factors which lead to secondary metabolite build up and i also think oxygen level and nitrogen fixing can come in to play. my plan for a larger room is to simulate high altitude by depleting oxygen. and i think the best way to do that is by using a burner since it will also add co2, infrared heat, and humidity as well. the dimlux 400v de 1000w hps have an active extraction port and also have a self dimming capability with a leaf surface temp thermometer. you set the surface temp and the light will dim if it reaches too high. it will take some dialing in but i think this could lead to some great results.

Mine is rather uncontrolled. But I have some nugs so dense you need a pick to break them up. Should be an interesting run though getting into spring the CO2 will be less. A simple pilot light puts out quite a bit of CO2 in a small area.