Slow Growth & Poor Root Development

Hey all, been having a bit of a puzzling time over the last few months trying to figure out whats up with my setup.

The plants always look healthy and nice and green, but growth has seemed quite slow and when coming to recycle the pebbles from the pots after harvest, the rootball's are frankly pathetic.

I'm running a Wilma system with the 6.5L pots and after approx 4-5 weeks of veg and then 8 weeks of flower, the roots were still mostly just long stringy runners down to the bottom of the pot where they had managed to form a "mat" across the bottom of the pot, but that's about it!? I was expecting the pots to at least be fully rooted

Also noted that the roots always seem very skinny and stringy, not the big fat fluffy white roots you see in a lot of peoples pics. They look perfectly healthy, just not much of them.


My wilma was using "custom" drip rings which circled the inside edge of the top of the pots and "jetted" the water out from the 4 corners towards the middle of the pot.

As far as process goes, I usually clone in 1" RW cubes then drop straight into the pebbles and off they go..

Does anyone have any suggestions as to why I have been getting such crappy root development? I am sure that it's whats leading to the slow growth and poor yield, I'm just unsure as to why.

Is it possible that my previous "drip ring" setup was causing too much water to end up straight at the plants stem and so the roots never went searching for water? Was I not watering enough? Or perhaps too much?


Thx all, would like to get to the bottom of this, as you can imagine its rather frustrating

Maybe stick the 1" rooted cubes into 16oz plastic cups w holes in the bottom and your media until the roots fill it up then into the 6.5l.
Temps Too cold?

I did consider going the "pot up" route, of a smaller container first and after doing a fair bit of reading around the general consensus seemed to be that it shouldn't be needed in hydro?

Temps are in the 20-25c range always and humidity is good... I was wondering about water temp though.. The res is ontop of carpet & underlay so should be reasonably insulted from the floor, but I did wonder if perhaps my res is too cold?

Are they getting a break to dry out or just running 24/7?

Started off at 2 waterings per lights-on period, increasing over time to 4 waterings as is commonplace.

Tho I am wondering whether the design of my top-feed rings were causing the middle of the pot to stay too wet and causing the plant to not spread out much.

I only use the 1" RW cubes to root in, so it's not like there is a big lump of RW in the middle staying soaking wet while all the pebbles have dried out, but I am struggling to think of another reason as to why the roots never really spread out very far. After 1+ month veg, I was expecting the 6L pots to be prettymuch full.

I suspect you are right, the custom rings were my first thought. I can see using them while your one inch cubes take hold in the medium, but after they do it is probably too much water and not enough air..

too wet

too wet

definately too wet
I used small cubes rockwool cut from a slab 2inch x 2 inch x 3inch deap but i wrapped in black/white plastic,kept in a tray and let a rootmass build up before potting up.
im ebb/flow buckets in hydroton i dry out your almost NFT with constant flow
use a timer let roots search for moisture

https://www.icmag.com/ic/album.php?albumid=27654&pictureid=610738

Andyo said:

definately too wet
I used small cubes rockwool cut from a slab 2inch x 2 inch x 3inch deap but i wrapped in black/white plastic,kept in a tray and let a rootmass build up before potting up.
im ebb/flow buckets in hydroton i dry out your almost NFT with constant flow
use a timer let roots search for moisture

https://www.icmag.com/ic/album.php?albumid=27654&pictureid=610738

Click to expand...

Its not a constant flow, it is on a timer, 15 min twice daily to start, increasing to 4x a day later on. Problem seems to by they just weren't throwing out much roots, resulting in a very underwhelming plant.

In recent runs I had cut back on a lot of the "superfluous" additives / boosters etc.. along with slowing reducing the feed strength to hopefully find that "sweet spot" so many speak of, where EC & PH in the tank stay prettymuch stable as the plants consume in equal measure, never did achieve it =/

Starting to wonder if stripping back on all additives and nute strength is what may have helped the problem along too..

The plants never really seemed deficient in anything and didn't show the obvious signs of hunger, but maybe they were just "idling along" on what they could manage, I dunno. I've noticed a lot of skinny growth rather than nice chunky branches, along with a lot of purpling of stems and leaf stems etc.. I know this can just be a genetic trait, but seeing it over 3 diff strains so maybe related to hunger?

I also used to use rhizotonic and I have noticed in recent cloning rounds that my results while still 100% successful, didn't have the same kind of "explosion" of roots from the cube, more just a handful spread around it.

Make sure there is more then enough in the water, air stone will work great
Also there is going to be bacteria and fungus in the system better to create an environment that favours the beneficial ones. Introduce good bacteria,fungus and enzyme into a highly oxygenated water environment that is 70 f . is a recipe for robust root development.

mother plants for cuttings

mother plants for cuttings

Devilman said:

Its not a constant flow, it is on a timer, 15 min twice daily to start, increasing to 4x a day later on. Problem seems to by they just weren't throwing out much roots, resulting in a very underwhelming plant.

In recent runs I had cut back on a lot of the "superfluous" additives / boosters etc.. along with slowing reducing the feed strength to hopefully find that "sweet spot" so many speak of, where EC & PH in the tank stay prettymuch stable as the plants consume in equal measure, never did achieve it =/

Starting to wonder if stripping back on all additives and nute strength is what may have helped the problem along too..

The plants never really seemed deficient in anything and didn't show the obvious signs of hunger, but maybe they were just "idling along" on what they could manage, I dunno. I've noticed a lot of skinny growth rather than nice chunky branches, along with a lot of purpling of stems and leaf stems etc.. I know this can just be a genetic trait, but seeing it over 3 diff strains so maybe related to hunger?

I also used to use rhizotonic and I have noticed in recent cloning rounds that my results while still 100% successful, didn't have the same kind of "explosion" of roots from the cube, more just a handful spread around it.

Click to expand...

where are you taking cuttings from ?
From your own mother plants ?

Yep, cuttings are from healthy mothers

rooting hormone

rooting hormone

Devilman said:

Yep, cuttings are from healthy mothers

Click to expand...

Ive had more than one grow room running at the same time less than a mile apart ,same kit, everything.

The new place cuttings got better and better so much so that didnt even keep mothers took cuttin of fresh vegged cuttins 4weeks old and normaly thats a no no,

Thinkin back we had slightly more humidity and i had changed the rootin hormone same type new tub
maybe that
your rooting hormone
As you say its the first weakness showing.A

Could be, my clonex is getting on a bit now, tho its still plenty thick a gloopy

Even so, I doubt it's to blame for the slow development once they are rooted & in the main pots.