Question about Reservoir Sizing

I desperately need a guide that gives cannabis nutrient needs in a QUANTIFIABLE manner such as grams per plant mass, grams per area, etc. Can someone please point me in the right direction?

If I knew how much nutrients approximately, say per kilogram of cannabis uses per day, I could better guess when to change the nutrient solution. Every suggestion I come across is arbitrary and does not take into account the variables like nutrient concentration, reservoir size, plant mass, etc.

Niko83 said:

I desperately need a guide that gives cannabis nutrient needs in a QUANTIFIABLE manner such as grams per plant mass, grams per area, etc. Can someone please point me in the right direction?

If I knew how much nutrients approximately, say per kilogram of cannabis uses per day, I could better guess when to change the nutrient solution. Every suggestion I come across is arbitrary and does not take into account the variables like nutrient concentration, reservoir size, plant mass, etc.

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I think you answered your own question. There are variables and no one can tell how much nuetrients are needed, the plant tells you.

Most nutes have a feed schedule. I'd start there and then fall the plants. They will tell u what they need

So basically I will have to check EC, look for deficiency signs, etc. and decide when to change the reservoir. Fair enough.

I have a master's degree at guerrilla farming and some experience with indoor soil gardening but very little with hydroponics. I just have finished building a 2 sq meter cabinet for a high density SOG garden. I am planning to put ~70 clones to 10 Aquatrays with coco slabs. They will be drip-fed from 2 separate reservoirs with a total volume of 240 liters. How long would you say those reservoirs last before I need to change the nute solution?

Niko83 said:

I desperately need a guide that gives cannabis nutrient needs in a QUANTIFIABLE manner such as grams per plant mass, grams per area, etc. Can someone please point me in the right direction?

If I knew how much nutrients approximately, say per kilogram of cannabis uses per day, I could better guess when to change the nutrient solution. Every suggestion I come across is arbitrary and does not take into account the variables like nutrient concentration, reservoir size, plant mass, etc.

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My approach to sizing a rez is based on watts of light used.

I use a minimum of 25 gallons per every 1000 watts------and usually lasts for 6-8 days-----then pump out and reload.

I also run my veg plants (once large enough) and flowering plants from the same rez-----same nute mix all the way through.

A~~~

Niko83 said:

So basically I will have to check EC, look for deficiency signs, etc. and decide when to change the reservoir. Fair enough.

I have a master's degree at guerrilla farming and some experience with indoor soil gardening but very little with hydroponics. I just have finished building a 2 sq meter cabinet for a high density SOG garden. I am planning to put ~70 clones to 10 Aquatrays with coco slabs. They will be drip-fed from 2 separate reservoirs with a total volume of 240 liters. How long would you say those reservoirs last before I need to change the nute solution?

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It will depend on the stage of growth you are at with probably not more than 5-7 days when in full on stretch flower I would guess, perhaps even less if their thirsty . I run 100 liter res's with 6 plants each and I am lucky to get 6-7 days before needing to refill but I don't top up which you could do, I just find things work better refilling. My PH will start to drop off near the end of a cycle and that's when I change it out. I run flood and drain so different but water consumption would probably be comparable. Also good luck, you kinda are starting same as me. Big outdoor shit and not so big indoor. Indoor is mucho easier , no bugs draining your blood .

Thanks for the insights guys, much appreciated.

Budley Doright said:

Indoor is mucho easier , no bugs draining your blood .

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LOL, you reminded me last year when I lost the top half of my best guerrilla plant not to bugs but a damn goat. I only check my outdoor plants when they are ready to harvest but this one was so beautiful, I decided to give it another week to fully ripen, only to find it eaten by a goat next week. I can't wait to see some beauties in my new set-up. It will take another month until I can take some cuts from the mothers.

Niko83 said:

Thanks for the insights guys, much appreciated.



LOL, you reminded me last year when I lost the top half of my best guerrilla plant not to bugs but a damn goat. I only check my outdoor plants when they are ready to harvest but this one was so beautiful, I decided to give it another week to fully ripen, only to find it eaten by a goat next week. I can't wait to see some beauties in my new set-up. It will take another month until I can take some cuts from the mothers.

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A goat, hah. I get beavers, muskrats, and coons but no goats. I wish I could leave mine but they needed tending at least weekly which damn near killed me lol. I'm only doing 20 outside now and their close but more risk .

I hope you put access to the back of cabinet . She's gonna get busy in there lol.

Budley Doright said:

A goat, hah. I get beavers, muskrats, and coons but no goats. I wish I could leave mine but they needed tending at least weekly which damn near killed me lol. I'm only doing 20 outside now and their close but more risk .

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I live in a coastal village so I plant a few in the village's pasture which has very good soil and a lot of free ranging goats. LOL, free fertilizer, I just pick them on the site and fertilize my plants. In my experience if you pick a good place, farming cannabis plants right under people's noses works exceptionally well when you blend them with the local plants. The village is teeming with vacationers in the summer but the pasture rarely gets visitors except for the goat herders who obviously don't care about or recognize my plants. I mostly use dirt-cheap seeds from bird seed suppliers and herbalists which show great vigor and pest resistance because they are wild varieties. Some of them turn out be even better than those expensive breeder's seeds.

The only hard part is to eliminate the males. I either have to germinate them at home and transplant the female seedlings or plant seeds directly and pay another visit to cull the males. I opted for the second this year as carrying a pocket full of seeds and some water is way easier and I don't mind a few seeds in my crop if I cannot eliminate all the males.

I hope all those animals leave a few good nugs to you, good luck.

Budley Doright said:

I hope you put access to the back of cabinet . She's gonna get busy in there lol.

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Unfortunately I had very limited area in my room so there is no back access to my cabinet, it is leaning against two walls. But I can get under the trays for maintenance if need be, there is ample space under the trays. Hopefully it won't come to that.

Here is a pic of roots 23 days after cutting using hydroguard and a bit of vitanimo

Flood and drain is my fave. I use 2x50 gal res for each 4x8. 1x50gal for a 4x4.

Nute change every TWO weeks. I make my own nutes, pretty much equivalent to AN connie. Not being cheap in 2 week changes, just lazy Weekly res changes= pain the ass. Having big reservoir = less work. Having good nutes= makes it possible.

Hydroton, 5 hour flood sched. LED's (25w sq.ft V29's and some cree3590 @ 1400. A couple rails @ 2100 ma). ,= 78f flower room for me with no AC cooling. I add a bit of cal-mag + pk boost after the first week if tray has a lot of mature girls. PH balance once or twice per 2 week fill. I let it run from 5.8 through 6.8. I run straight 700ppm. Thats what my girls seem to want.

Flood and drain is the only way to tell what your plants want to feed at btw. If you over ppm, you will see your ppm rise. If you under PPM you will see a significant dropoff. Find a sweet spot and you should see a slow steady decline between res changes. Proper PH will correspond to proper feeding: you should see a slight and steady increase in your ph readings day to day.

As far as getting the measurements you want. Impossible. Strains will have varying transpiration/ nutrient utilization characteristics not just from DNA, but from growth stage and full enviro factors: soil pack, humidity, temp, air flow. All HUGE variables. Too many to get quantifiable data you want. -Better to just find out what plants want under your conditions. Rather than ALL conditions, which again, is impossible.