Hydroponics - roots in the water or not?

FishFlavoured · Jun 23, 2018

I have 10" diameter net pots in 5 gallon buckets. I will be using 7" of hydroton in each basket. I was planning to have the pots sitting 3.5" into the water with an airstone directly underneath each net pot basket. Each airstone will get its air from a 15 litre/min air pump with 4 outlets (3.75 litres/min for each outlet). So, about 2.5" of the roots will be above the water level and 3.5" of the roots below the water level. Of course, as the roots grow, they will just go deeper into the water. An overflow pipe will keep the water level constant and I will be supplying water with a submersible pump and each net pot will have 2, 1/4" lines coming from the pump. So, the hydroton will be constantly hydrated from the top besides being 3.5" into the water. Lots of water and lots of air!

Some people think that the net pots should be just above the water. Is there a problem with having the roots immersed in the nutrient solution? Do any of you see any problems with this arrangement? Thanks.

WelderDan · Jun 23, 2018

Roots can stay submerged completely as long as there is constant water movement to aerate the water. Constantly being submerged is only a problem if there is insufficient dissolved O2 in the water.

I myself don't run a constant level, but allow the rez to get low. The roots get exposed to air, and the resulting ph swing allows for a better nutrient uptake, as different nutrients are more available at different ph levels.

It's purely a preference thing. You can run it the way you are, as long as you have enough water movement to keep acceptable dissolved O2

Mlewis1987 · Jun 23, 2018

Be careful of keeping your water too high also. I ran an undercurrent setup and my floors weren’t level in the basement where i was growing and I would try to always keep my buckets filled , well the plants on the low side of the floor actually rotted away at the stem because they were to far into the water. Just something to keep in mind. Probably a freak thing that happened to me but I lost two plants over it at week 5 of flower. Good luck with everything

Douglas.Curtis · Jun 23, 2018

What is your ability to cool the nutrient solution?
When you can reliably and constantly keep the solution between 65F and 69F, a "Roots-In" hydroponic system is ideal. The roots can be fully submerged, as previously mentioned, but the stem must stay dry. Aeration of the solution is also needed constantly.

When you cannot control the root zone temps, a drip or e&f setup with hydroponic media will be significantly easier to keep healthy. I call these "Roots-Out" systems and with temps of 75F and higher they still create beautiful plants.

Keep your levels the same throughout the grow. Allowing a section of roots to dry out for a while (more than a few days) can cause issues when you raise the solution level and keep them wet all the time again.

FishFlavoured · Jun 24, 2018

Thanks guys. I will be able to keep my root temps at about 68 with no trouble at all. So, roots-in it is.

It never occurred to me that temperature was the key to success in a roots-in system. I've never seen it explained anywhere. It makes sense.

My overflow tube keeps the water level constant at about 3" below the top of the hydroton so the stem will remain dry. If the overflow pipe gets plugged, at 1/4" above the overflow level, a water level sensor will sound an alarm and turn off power to the water pump. Other than by evaporation/transpiration, it is impossible for the water level to drop in the buckets. Of course, now I need to make some arrangement for aeration in case of a power failure.

Douglas.Curtis · Jun 26, 2018

FishFlavoured said:
Thanks guys. I will be able to keep my root temps at about 68 with no trouble at all. So, roots-in it is.

It never occurred to me that temperature was the key to success in a roots-in system. I've never seen it explained anywhere. It makes sense.

There's a lot of confusion in this area, totally not your fault to be confused. I'm glad to clarify things for you, since it usually means much higher quality cannabis for you.

Ganoderma · Jul 3, 2018

It depends on several variables. Either will/can work as long as you have the right conditions for which ever way way you go with.

How where they transplanted into the 10inch net pot? This includes what type of medium they are in before being transplanted into the net pots. Are they going from one medium into a different medium? This can influence your water level after transplanting and until your roots start to grow out into the new root space.

If you keep the water level lower, you can always hand water from the top to keep the upper area moist enough for the roots until your roots start growing.

A variable water level at this stage can better for root growth.

Submerged roots will tend to grow downward. The side branching of these roots is much less then root that have a variable water level. Roots with a stronger side/lateral branching would be better to fill out as much of your net pot as possible.

Douglas.Curtis said:
What is your ability to cool the nutrient solution?
When you can reliably and constantly keep the solution between 65F and 69F, a "Roots-In" hydroponic system is ideal. The roots can be fully submerged, as previously mentioned, but the stem must stay dry. Aeration of the solution is also needed constantly.

You do want the root zone to be cooler then the air temps. Water temperature isn't always an issue where you "Have to" keep the water between 65F and 69F. That is another one of those variables that depends on your set-up and your other environmental variables.

Douglas.Curtis · Jul 4, 2018

Ganoderma said:
You do want the root zone to be cooler then the air temps. Water temperature isn't always an issue where you "Have to" keep the water between 65F and 69F. That is another one of those variables that depends on your set-up and your other environmental variables.

Below 65F and you get slow growth and nutrient deficiencies. No way to get around this.

Anyone contemplating going above 69F with a "Roots-In" system is going to learn the same thing everyone else has, it's stupid to tempt issues when you can easily keep your solution at 69F and avoid them. It only takes one instance to destroy your whole crop, so it's definitely something to avoid. My only intent is to make this process as smashingly successful as possible for anyone seeking to do this themselves.

Keep your temps in check and focus your resources on other areas.

Mlewis1987 · Jul 4, 2018

Good info in here. I had these same questions last run. Unfortunately I got bad/wrong answers to some of them and paid the ultimate price. Actually it pushed me entirely away from my undercurrent setup and I switched over to pots of coco. Glad to be here now though. Thanks for sharing

Dirt Bag · Jul 4, 2018

The water in my cloners is always 76°F, roots underwater, and I have never had a problem. Long, thick, white, fuzzy fishbone roots. Adding clearez or using water that contains chlorine or chloromines will greatly reduce the chances of any biological issues. Plants aren't bothered, in fact the right amount of chlorine is actually beneficial.

PetFlora · Jul 4, 2018

OP, you got some very excellent help here.

I'm a DIYer by nature, but I can't DIY these cool ass pots, which should make most of our hydro adventures a lot easier by eliminating potential root issues

Tent and drainback height restrictions meant installing the bulkheads on the sides of my totes, instead of the bottoms.

This grow pot system (link below) will eliminate some standing water in my F & D grow totes, as well as contain the roots in the bags

Maybe somebody here report on them

https://greenenvysupply.com/brand/oxygen-pot-systems/

hth

Douglas.Curtis · Jul 4, 2018

Dirt Bag said:
The water in my cloners is always 76°F, roots underwater, and I have never had a problem. Long, thick, white, fuzzy fishbone roots. Adding clearez or using water that contains chlorine or chloromines will greatly reduce the chances of any biological issues. Plants aren't bothered, in fact the right amount of chlorine is actually beneficial.

Your cloner is a "Roots-Out" hydroponic system. "Roots-Out" hydroponic systems benefit from higher temps in the mid 70's.

With Roots-In hydroponic systems, 65F to 69F stays clean without chlorines of any kind. Mine actually stay pristine throughout flower with only r/o add-backs. I dump the res one time, 5 days before harvest.

Big Nasty · Jul 4, 2018

Dirt Bag said:
The water in my cloners is always 76°F, roots underwater, and I have never had a problem. Long, thick, white, fuzzy fishbone roots. Adding clearez or using water that contains chlorine or chloromines will greatly reduce the chances of any biological issues. Plants aren't bothered, in fact the right amount of chlorine is actually beneficial.

chlorine is soon neutralized by organic matter otherwise you won't get algae with tap water.It's not 100% sure that you'll get root rot above 21C(70F)but better safe than sorry plus DO increases at lower temps.The best temp for me is 16-17C(60-62F) and water touching the netpot,i've never had any problem,white healty roots and happy plants.

Dirt Bag · Jul 4, 2018

Big Nasty said:
chlorine is soon neutralized by organic matter otherwise you won't get algae with tap water.It's not 100% sure that you'll get root rot above 21C(70F)but better safe than sorry plus DO increases at lower temps.The best temp for me is 16-17C(60-62F) and water touching the netpot,i've never had any problem,white healty roots and happy plants.

How do you propose OP chills their reservoir? Buying a chiller? Rather impractical for most, no? We have a chiller on the 100 gallon reservoir. I think it was $600 and we've been able to keep the reservoir temperature at 73° in a 78° room with it off. Was chilling to 64° and have seen absolutely no difference with it off. Now it just supports a fan.

Big Nasty · Jul 4, 2018

Op has no problem to keep the water in the right range,he wants to know hte proper water level and i had healtier rootmass if submerged,i agree that a chiller is pricey and it's up to you to decide if it's worth.You can go,as Douglas Curtis says,with a chiller and chlorine-free or you can use a sterilizing agent at higher temps but water can hold more oxygen in the 60's.

Douglas.Curtis · Jul 4, 2018

Dirt Bag said:
How do you propose OP chills their reservoir? Buying a chiller? Rather impractical for most, no? We have a chiller on the 100 gallon reservoir. I think it was $600 and we've been able to keep the reservoir temperature at 73° in a 78° room with it off. Was chilling to 64° and have seen absolutely no difference with it off. Now it just supports a fan.

I take it you're running a "Roots-Out" hydroponic system, which has zero need for cooling in a regulated grow environment. Res temps are critical when the roots of your plant are constantly IN the nutrient solution, hence the label of a "Roots-In" system.

As for chilling a res, most small growers can hang/place their air pump in the a/c cold air flow. Don't have an a/c and cold air? You should really be running a Roots-Out hydroponic system.

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Hydroponics - roots in the water or not?

FishFlavoured

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