How to feed a reservoir: Non recirculating


Well-Known Member
Right folks time for another how to thread for my sig.

So how do we feed a reservoir then?
Lots of people get put off hydro growing when they see the dramas people go through faffing about with pH levels and obsessing over ppms.

The truth is if you set the Res right you don't need to do much at all.
If the pH goes out of range within 5 days you're doing it wrong and it should need a top up by then so that will fix it anyway.

A little trick that only reservoir growers have up their sleeve is that the ppm e/c meter actually tells you how strong to make the feed.

If the ppm is rising then the feed is getting stronger.
If the ppm drops then it's getting weaker.

Easiest way to keep it perfect is to start at 200ppm + your water. Once the ppm starts to drop by 10-20 per day you go up by 50%.
Then in a couple weeks time once that starts dropping by 10-20 per day again you go up by 50% again.
Always up the nutes by 50% once the drop comes .
That pretty much garuntees to keep it at the right strength.
Saves you about 75% on the nutes bill too :)

You go in at ph5.5-5.7 for veg then 6.3-6.5 for bloom.
Only pH adjust it once it hits iether end.
That pH swing lets the plants absorb everything as best they can.
And as your feeding pretty much exactly what the plant is taking in the pH will rise slowly in veg then drop a bit quicker in bloom as the plant is bigger.
You'll be topping it up more regularly then anyway so it doesn't cause any drama.

The pH swing is partly caused by root secretions which change when they flip to bloom. Hence the rise and fall. But the effects will happen faster if the feed is too strong or too week.
By feeding this way you really shouldn't ever have to pH adjust it out with top up and Res change day.

What you feed it is upto you.
Personally I start off with
100ppm veg nutes, 30ppm scillica, 30ppm root boost and take it from there. They'll be more than happy with just veg nutes though if that's all you've got.
Scillica must be used exactly as stated on the bottle.
Root boost it's upto you. I use roughly quarter strength the full grow. Sometimes I don't use it

If you're using r/o water you'll definately need calmag to start with aswell. 50ppm of that then just gotta judge it from there.

Also it's best to use some sort of product to keep the Res clean.
Sm-90 is my personal favourite. Runs the Res sterile. Stopped making it just now but it's still on eBay. It should be back for sale soon.
Other top choice is hydroguard which is beneficial bacteria that kill any bad bacteria. The opposite of sm-90 but same result.

When feeding this way you pretty much eliminate 90% of possible dramas.
The only things you should need to watch for are...

The bottoms going yellow.
That's nitrogen deficiency. Up the veg nutes by 50%

Mids lose colour and go blotchy or rusty spots appear that magnesium and calcium deficiency so up the calmag by 50%

Tops going yellow, once you know it's not the lights being too close, is iron deficiency.
You can find that in a bottle of micro boost or do what I do and buy calmag with added iron.

For bloom you need bloom nutes and a pk booster.
Bloom nutes go in at the same strength the veg nutes were at.
3 weeks into bloom, ramp it up a little if they need it and start the pk booster at quarter of whatever it says.
If the tips don't burn after a few days then try 50%. If you see any burnt tips appearing anywhere then back off.

A few weeks later youll notice the ppm starts rising really quickly. That's the plant finishing herself off.
People think you need to flush them but they do it themselves anyway if you let them.
Half all the nutes.
Next week half them again.
Next week half it again and you should be nearly done.
She's stopped feeding now anyway which you'll see in the ppm.

That rise in ppm towards the end is also your cue to start using bud hardners or ripening agents if you want to use them. Not something I bother with though so have to ask someone else about that one lol.

Bear in mind indicas will finish massively faster than most sativas so adjust timings accordingly.

That'll do for now I'm off out for a bit :)
Bring it on brother, can't wait . You seem to have a damn good handle on this hydro. Makes me feel better at what I'm seeing in my own system.
It's pretty straight forward mate I just keep it simple so most things can never become an issue. I'm gonna change that a bit. It's not quite worded right some of it but not bad for a first draft.
It's all in the ppm though. If you can keep that just dropping then all you have to really look out for is the 3 main deficits. Everything else just looks after itself so you don't really need to know it.
So I've got an ec. slowely rising , a ph slowely dropping and buds all the color of a rainbow so heavy they are starting to fall over, starting into week ten of flower. Some leaves are drying on the stem and heading for the buds but be damned if I can see much in the way of amber trics. Prior commitments are going to make me harvest soon, but wish I could wait another week or so.

So I've got an ec. slowely rising , a ph slowely dropping and buds all the color of a rainbow so heavy they are starting to fall over, starting into week ten of flower. Some leaves are drying on the stem and heading for the buds but be damned if I can see much in the way of amber trics. Prior commitments are going to make me harvest soon, but wish I could wait another week or so.

Aww mate another week or 2 would do her well. Shes ready enough though if needs really must. Sometimes life gets in the way of our wonderful hobby. Just gotta go with the flow eh :) looks like shellbe a cracking smoke anyway and thats all that matters :)
I can possibly let them go a little longer and time the cut so they can hang while I' away playing in the sand. Only problem I see with that is right now our rh. is hovering around 70 and only going to get worse as the summer gets along. Concerned about not being here to watch over them as they dry.
Hmm yeah thats always gonna be a gamble mate. Ive only had bud rot once and i caught it quickly so only lost a few buds but if i hadnt been there idve probably lost the lot. Not sure its a risk id take. Think id rather know for sure i had something decent than gamble it all and only maybe get something thats a bit better.
My thoughts as well. But another four or five days is doable, which gives me a week and a half to hang dry and jar, and a few days of burping. Not crossing any national borders so a jar can go with me, won't be fully cured but a good tester. Looking forward to it, toes in the water, ass in the sand, with a big fat doober in my hand, ain't life grand. At times anyway. lol
Oops, i cant edit the origional post anymore so heres a few other things I should point out aswell to cover the inconsitencies i wanted to change...

I forgot to mention temperature. Ideally you want it 18-20*c roughly. Officially im telling you thats the right thing to do....
but dont panic if it goes over for a bit. Mine runs at 22-25*c most of the time and doesnt give me any grief. Grew my profile pic during summer so she was 27-30*c most of the time and it clearly never caused any problems. They get sressed out real quick if it hits 31*c but thats fairly hard to do anyway lol.
That was while using sm90 to keep things sterile. Any other sterilising agent should have the same effect.

The other res cleaner i mentioned is the hydroguard, positive bacteria type products. Ive admitedly never used them but most people that do ive notice really dont want it going over 25*c.
If anyone has any thoughts on that matter please feel free. Ive always ran sterile so theres no bacteria in my res at all. Temps have never been an issue so ive never had to know :)

The bigger the resevoir you use the slower all these effects will be and the more precisely youve gotta look at the ppm.
Ie, i use 20L resevoirs which is a pretty common size, about 5 gallons per res for most people.
If you got upto 40-50L the ppm and ph will move twice as slowly but still be easily monitored after the first 2 weeks once theres a decent root system.

Start 80L though and it will hardly move for a good few weeks as theres just not enough roots to make much of a difference

This is also why i pointed out that this method is for "non recirc systems" in the title. Theres generally just too much water in them so the ppm drop would be really hard to see whilst equating for evaporation etc.The likelyhood is that my method of waiting for the ppm drop would result in underfeeding and deficiencies so it would be better to have some sort of a schedule for those systems.

This is a beginners guide to growing so i have missed out certain things. Lots of toxicities and deficits i havent covered and lots of other problems that can arise but by following this method they really should never become an issue that you need to know about.

Ahhh that feels better. Off to get stoned and play forza 7 now :)
Thanks for the write up @Barney86 your presence and knowledge is missed around here (went back to another site a month ago), just before you left you asked me if I had anything bubbling yet, well I do now and miss seeking your advice and was pointed to this thread by @N420

Hope all is well with what ever you are growing these days and what site you are on, they're lucky to have you in their forum.

Happy growing!
NFT. Help?
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