[Drlovekek]

Hi, I have recently started growing in rockwool and I am starting to have problems.
The plant seems to be yellowing with some burns on the tips, its curling down bit, some of the lower leaves have dried out and the roots have turned brown.
What can be causing this?

[mojave green]

Roots need more oxygen

[Drlovekek]

Originally Posted by mojave green

Roots need more oxygen

And how can i fix that?

[EvergreenState]

Put that cube in a larger rockwool cube. What is your ph, what nutrients are you using, how often do you water? How much light, what are your temps., it could be any number of things. As soon as you get roots to grow out of the bottom of the tiny cube you need to put that small cube in a larger cube or a larger pot of soil or soilless mix.

[SkunkFunk49]

It looks like they are hungry. Also try to block the light from the roots. And you can always just throw it in a pot with soil if all else fails

[mojave green]

Originally Posted by Drlovekek

And how can i fix that?

Let RW dry out a bit more between watering

[Phaeton]

Leaves evaporate water which is absorbed through the roots. Out of the myriad factors affecting both, the main driver is surface area.

More leaves have more evaporative surface. If the leaves outgrow the roots then the problems start.
Inflow through the roots is controlled by the area available for water to flow through. Small adjustments can be made but size matters almost exclusively.

Mohave green's advice to allow the rockwool to dry out some before rewatering is giving a signal to the plant to grow more root.
Another long term procedure is with an infra red light supplement. Properly timed 840 nm infra red causes faster growth in plant extremities (root tips and branch tips). Not recommended for budding plants due to excessive small leaves in the buds.
Volume is the largest single factor, sizing the plant for the container for each stage of growth eliminates the problem. Rootbound plants reach a tipping point even transplanting into a large container will not fix. The knotted mass slows the flow even if new roots are added.

Keeping ahead of the growth curve is as important as the nutrient mix or lighting.

[Dropped Cat]

Would pinching leaves have an impact to promote root growth at this stage, I wonder.

[mojave green]

Originally Posted by Phaeton

Mohave green's advice to allow the rockwool to dry out some before rewatering is giving a signal to the plant to grow more root.

yes, and oxygen also kills anaerobic bacteria that cause root disease. similar to allowing a kitchen sponge to dry out before reuse.

[EvergreenState]

[quote=Phaeton;8232885]Leaves evaporate water which is absorbed through the roots. Out of the myriad factors affecting both, the main driver is surface area.

More leaves have more evaporative surface. If the leaves outgrow the roots then the problems start.
Inflow through the roots is controlled by the area available for water to flow through. Small adjustments can be made but size matters almost exclusively.

Mohave green's advice to allow the rockwool to dry out some before rewatering is giving a signal to the plant to grow more root.
Another long term procedure is with an infra red light supplement. Properly timed 840 nm infra red causes faster growth in plant extremities (root tips and branch tips). Not recommended for budding plants due to excessive small leaves in the buds.
Volume is the largest single factor, sizing the plant for the container for each stage of growth eliminates the problem. Rootbound plants reach a tipping point even transplanting into a large container will not fix. The knotted mass slows the flow even if new roots are added.

Keeping ahead of the growth curve is as important as the nutrient mix or lighting.[/QUI
I agree. If you wait too long to transplant then the plant could be beyond help. That is why I said a person needs to transplant as soon as roots start to poke out of the small cube. Newly germinated seedlings and cuttings are meant for very short term growing in the small cubes.