Indoor Tips: Hemp Mods

I want to start a thread to discuss ways to grow smokable hemp indoors. Part of the idea is to adapt some marijuana grow methods to hemp. For example, there is no concern with numbers so trees are out of the equation. Hemp, even quality indoor, is not as valuable as marijuana so the latest and greatest DE or Quantum board may be overkill.

I have dabbled in NFT, drip emitters, ebb and flow, DWC, coco, soil, rockwool, turface, perlite, hydroton, and peat. Every method and medium has its advantages and drawbacks.

The most reliable was PPK or passive plant killer method if anyone remembers that thread on icmag. Massive roots and yields from large plants and great buffering from environment fuck-ups.

PPK is too labor intensive beyond a few plants because of the use of tailpipes for the roots. I have grown dense sea of green and want to get back to that. Better light penetration, faster turnover, better bud ratio and structure.

I want to try shelf ebb and flow or soil beds. I have 400sf and 15’ ceilings. I have run 4" rockwool blocks in e&f at 9 per sf. That was great for yield.

Really want to go organic. I’ve read some people say that soil is actually more of a health risk to smokers because of heavy metals etc. Anyone running soil beds for sea of green and can speak to their experience using it vs. hydro?


In a similar position. Growing hemp indoors in soil and dwc.It is hard to bear hydro for production and turn around. But consumers are wanting to see organically grown. Aquaponics is cool, but doesn’t produce like true hydro.
Curious to hear more about heavy metals in organic. That is news to me.
Running berry blossom and relief CBG.


Here is something discussing why you have to be careful where you souce your soil and compost. Sure wish someone would perfect organic hydro but coco and Pure Blend ain’t it.

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Aeroponics. Well pump, cycle timer, and pvc manifold inside a table. The lid is the most expensive part. I like 2 pieces of fiberglass frp sandwiched around styrofoam.


Welcome to the future @Dirt_Diggler!

Heavy metals are more likely to come from contaminated soil, whether grown organically or not. Good organic inputs can be found without heavy metal contamination, but I’m sure plenty of organic materials could contain heavy metals, too. Some things like Azomite have been debated for heavy metal content, but even the cleanest hydro nutrients can contain traces of heavy metals, too.

Check out this post from @AgTonik:

The pdf he uploaded has some great info on the topic as well.

Edit: That whole thread would be a good read regarding heavy metals.

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You running organic nutes or would it clog the jets?
Maybe Earth Juice?

Organic would be hard to pull off. I have never seen it, but anything is possible with enough work. If you are going through an organic certification agency, they would be the ones to ask about what they consider organic. When I was growing greenhouse lettuce, omri standards said that everything had to be food safe plastic, which is absurd.


@BigM Thanks for the mention. We are possibly thinking about pouring a bunch of money into research for soil remediation, particularly for cannabis. The primary modes for remediation are going to be proper liming, gypsum, humates with carbon and fulvic acid chelation and as an electrolyte in particular. (Although it is outside the scope of our business I suggested organic surfactants and mycoremediation as possible tangents as well)


Is this true hemp, or just CBD, CBG clones your trying to grow?

As hemp are mosty sativa dominant populatiins breed for seed and fiber you might want to select moms first and thengo for a full indoor.

Otherwise your seed producer should tell you the major characteristics feom which you could then apply certain methods to get the best put of your grow…


Have you looked into the michorrizzae translocating metals depending on which population and presence? This could be a usefull tool to just cut the flowers otherwise its supposedly stays in the roots…

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CBD…I have Z6 x Harle Tsu, Ceiba, Lifter, Hawaiian Haze, Pine Sap Kush…looking for compact growth so that probably eliminates a couple of the strains but I will pop them and see

As I see these strains perform outdoor I would say that they will be a sinch for you to grow if you have prior experiences with cultivation.

Most are derivates from hybrids wich are mostly known and their charachetistics…

Your gonna have fun with those I can see :slight_smile:

Has anyone successfully run organic hydro with a biofilter?

Yeah, but only for vegging plants, which are fairly easy to grow in fish waste, because it is almost entirely nitrogen. I have used the plastic bio balls as filter media. Hydroton works, too.

We had a long discussion on here recently about whether or not aquaponics can work for flowering. I said no, but the more correct answer is that it can be done if the fish waste is moved through a large bed of lettuce or any leafy green that will pull out most of the nitrogen, to get the npk values closer to equal.

One surprising result for me was that my plants in the ground outside produce a much higher percentage of cbd. Both indoor hydro plants and outdoor plants in fabric pots only gave me about 60% of the cbd as the plants in the ground. I don’t know if everyone has the same result, but that is what has kept me from running an indoor operation at a large scale. Your 18% varieties are going to be hard to sell if they come back testing at 12%, even if the buds look perfect.


Thanks for the detailed response. My experience with smokable is limited admittedly but I seem to find that a lot of people judge quality more so on bag appeal and terpenes than absolute CBD percentages.

Talking with a grower who ran Earth Juice but said he had to supplement with micronutrient 5-0-1 briefly for added nitrogen. Botanicare has OMRI on some of their products but Ive been told that a complete formulation, with Ca and P in suspension, will clog lines.

Yes definetly… I see indoors hit from 10-13% and on field those ladies go anywhere from 14-17%…

I see that its a correlation of overproduction if your leave them to scenescence,as the cbd keeps rising,as opposed to thcs that have a definet peak and then the content starts dropping… Papers have been published and I would like to reproduce those finds in a scientific enviroment but allas time is barren…:slight_smile:

All the clone producers claim 0.2 but on field anything can happen, expect that heeheh

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Root rot is a bigger problem than clogging. A lot of organic nutes are a suspension of solids. When that liquid flows over the roots, they filter out those solids, which stick there and are too much bacterial food, anaerobics take over and rot ensues. So even if you did not use aquaponics, filtering is indeed important.


Humic acid, some algae, and a good soil, and a tuned in compost tea is all we use with good results…12-15% cbx and 2.3% terps…

But the power of the everlasting creator makes the difference here bigtime.

Make room for a UV light intthere

Edit: and some molases :slight_smile: dont forget the molasess!

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Yes and literally smells like rotting baby diapers. The ability for bacteria to make organic nutrients soluble to plants is a very smelly proposition.

Aquaponics can be done easily with no other supplements as long as you use calcium and potassium carbonate for pH up. If you aren’t getting yields you would like, you can always do a soil/hydro dual pot hybrid system for hemp/cannabis with aquaponics.