My 99% fully automated grow. Finally added the fertigation part! How much to fertigate per plant per day?

Here it is. I'm running Dr. Bugbee's formula of soil-less mix and I've got a 200 litre reservoir connected to a an RV/Yacht pump and wifi irrigation timer/soil moisture sensor. I'm using smart plugs, co2 wifi controller, wifi hydrometer, infrared remote, dehumidifier and webcam. All is working through the cloud and mostly interconnected.

The latest addition was my fertigation setup as depicted in the attachments.

I've just got 1 question about how to best organize my fertigation schedule. Also I would be keen for any advise or warnings based on the photos I've shared below and following desription...

So I'm using 4x 5g pots in the 4x4 with 580 watts of led/cob and co2 tank. At around 29 degrees C. I've just flipped to flower (the scrog is fuller than full!).

How much should I be fertigating?

Now I've got it at 3 litres per plant per day. This is spread out so 1.5 litres per plant at 9 AM when they wake up. Then .75 litres for lunch and .75 litres for dinner.

Upon second thought I was concerned that this might be too much? Maybe lower to half that amount or skip a day between watering days?

It's funny because I set the wifi irrigation machine wrong the first day (I thoughts minutes were seconds) so they got a month's worth of fertigation in 1 day but they came out fine from it hahaha. They can take a lot of water/fertigation but I dont want to be wasteful.

I understand in this type of setup, it is good to give a small amount of water frequently? The most waterings I can do per day with my controller, is 3x. Not less than 1 minute per time. Maybe 3 litres per 5 gallon per day is too much? Should I cut this to 1.5 or 2.2? Maybe spread those 3 litres of 2 days? Or have a dry-down day between fertigation days? What is the best strategy here?

I think the plants are healthy and doing well in either case. Just looking for advice, and I don't want to waste the reservoir contents if I am overdoing it unnecessarily. I am new to soiless and haven grown for 20 years until covid hit...

Nice setup!
I’m completely new to growing and jumped into Bugbee’s method straight out of the gate. I’m currently hand watering with 20-10-20 every three days until I have about 10%-20% runoff with EC readings between 1 and 1.5, as Bugbee suggests.
I don’t know much about automatic watering. Is there a way to measure EC out? If you can and are within 1 and 1.5 you should know you’re feeding your plants the optimum amount and frequency.

True true about the runoff. Good point.

Will try to check runoff ppm and observe this...

Every 3 days seems slightly sparse with Bugbee medium unless they are small. How are your babies looking and how old?

Overgrowtho said:

True true about the runoff. Good point.

Will try to check runoff ppm and observe this...

Every 3 days seems slightly sparse with Bugbee medium unless they are small. How are your babies looking and how old?

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You are correct about sparseness! I watered just after writing the previous response and the ec was up to 1.8.
I'm going to start watering every two days, now. See how that turns out.
I'm just growing in a 2x4 tent so, I technically have one plant going. I flipped to flower 2 weeks ago and I think she looks pretty happy. Growing Blue Mystic in a 5 gallon fabric. There's a smaller plant located to the left that I grew a little later in case I failed on the first. She was flipped the same time. Her future is uncertain.

Every other day sounds better. That is what I ran before turning on the auto-fertigation. They are looking well.

For a first time grower you've chosen a great system and are doing good! Just shows how great this system is.

Thanks for your words of encouragement.
Bugbee, Utah State and Apogee are amazing resources that deserve more recognition.
Science!
Looking forward to your results, Overgrowtho.

What is the medium?

PJ Diaz said:

What is the medium?

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50% Peat / 50% vermiculite with some amendments to keep PH in check. 20-10-20 food required with every watering.

It's really best to watch this entire video, although I've time stamped it for the media section.

Ur watering schedule is going to change based on the size of the plant and the size of the pot. try to seet it by runoff aorund 1.2ec. so 1.3 going in 1.2 coming out. if thats 1 liter a day when the plant is small its going to be 2 liters a day or 1 liter twice a day when the plant gets big...

when i run bugbees method i water rather infrequently. at the most once daily. when im lazy i out them in kinda bigger pots and go every other day... the goal is just to get 10-20% run off and be at the ec u want.

also just a PSA to anyone u want to check ur calcium... bugbees method relies on medium ammendments and tap water for calcium magnsium sulfer.... if u missed some of the ammendments or dont have adaquet amounts of those things in your tap water u could be looking at deficiency in the cal mag sul department

Thanks @JonCreighton that helps.

I am using the same medium but a different nute package (dont have access to Jacks) than Bugbee. Mine already includes Cal and mag. Does it change my requirement for Gypsum and Lime? (I did amend those in as per his instructions, when making the mix).

I too am growing using the Bugbee method. This is my first official grow starting from seed and it's just bagseed 3 Jack Herer and 1 SFV OG. I want to become more familiar with growing before I spend money on genetics. I am watering by hand at the moment and I'm starting to see how having an automatic watering system would be very beneficial. I did my best to follow Dr. Bugbee's method and I think the only part I need to correct is using powdered Dolomite Lime rather than Dolomite Lime I currently have which looks like large salt. I was even able to find an store that sells the 20-10-20 Peat Lite Special.

Vizzaro said:

I too am growing using the Bugbee method. This is my first official grow starting from seed and it's just bagseed 3 Jack Herer and 1 SFV OG. I want to become more familiar with growing before I spend money on genetics. I am watering by hand at the moment and I'm starting to see how having an automatic watering system would be very beneficial. I did my best to follow Dr. Bugbee's method and I think the only part I need to correct is using powdered Dolomite Lime rather than Dolomite Lime I currently have which looks like large salt. I was even able to find an store that sells the 20-10-20 Peat Lite Special.

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I too, could only find the more granulated dolomitic lime. However, I have an old coffee grinder and got it into a fine powder with relative ease. I could only find powdered gypsum, as well.

BonnMac said:

I too, could only find the more granulated dolomitic lime. However, I have an old coffee grinder and got it into a fine powder with relative ease. I could only find powdered gypsum, as well.

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I used the old mortar and pestal.

Overgrowtho said:

I used the old mortar and pestal.

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Sometimes Stone Age tech is the best tech.

Overgrowtho said:

Thanks @JonCreighton that helps.

I am using the same medium but a different nute package (dont have access to Jacks) than Bugbee. Mine already includes Cal and mag. Does it change my requirement for Gypsum and Lime? (I did amend those in as per his instructions, when making the mix).

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i would still give the recommended amendments to the soil because they are there for ph balancing aswell and i dont think they would come close to the point of being toxic.

while im on the PH topic pete from some places like home depot or big box stores does not have the ph he states in his video... its like faux pete or something. u really have to source ur pete from a aggicultutal shop or something other than the big box stores... if u get the pete from home depot that has a ph of 5.5 already. when u add ur vermiculite and ur gypsom/lime ur going to be over ur ph target... so u really want to make sure ur getting the pete w a lower ph.

Overgrowtho said:

How much should I be fertigating?

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Fertigate to significant runoff. No one can tell you what your plants need. Monitor and adjust accordingly. More runoff won't hurt soiless mediums, just a waste of feed. (Still cheap with quality dry salts) In other words more is better for growth and preventing issues related to salt buildup.