Keesje
Well-Known Member
There are always discussions going on about root rot and low/high temperatures.
Some people are convinced that you have to keep the temperature of your reservoir below a certain point.
For example below 20°C / 68°F. Otherwise your roots will get all messy, brown, stinky.
I did some research about it already long time ago, and also visit commercial hydro growers regularly. Never could I find information about the claim for low temperatures.
On the contrary, most commercial growers agree that roots and plants develop best by temperatures higher then 20°C / 68°F.
But what about the root rot then?
I came across an interesting article. Not from some cannabis publication (who often don't understand science and biology and just repeat or misinterpretate what they read somewhere) but from a legitimate source.
The article is in Dutch, but Google Translate is my friend.
The cause of root rot is not always clear. An attack by, for example, Phytophthora can be mistaken for a Fusarium attack.
Causes of poor growth and symptoms usually start at the roots.
If the roots are in bad condition, this can lead to symptoms such as branch mortality and leaf spots in the aboveground parts.
A common problem is infestation by plant pathogenic fungi.
If these infect the roots, root rot often develops.
The roots can no longer absorb water and nutrients in severe rot. Plants will thus remain behind in growth, yellowing, withering and eventually dying off.
The symptoms that cause different fungi are not always easy to distinguish from each other.
Especially if the damage is at an advanced stage, it will be difficult to visually assess which fungus is the primary cause.
An attack by, for example, Phytophthora can be mistaken for a Fusarium attack.
A number of common fungi that can cause root rot are: Phytophthora, Fusarium solani, Rhizoctonia solani, Thielaviopsis basicola and Pythium.
The conditions under which these fungi can develop and infect the plant vary by species. Below is a short description of these fungi:
Phytophthora
This fungus is a primary pathogen. This means that it can infect healthy plants.
Phytophthora infects the roots after which it can cause rot in the stem base.
The spores germinate quickly at a low temperature shock caused by cold water.
Because of this, a Phytophthora infection often occurs during cold days / nights.
The spores of Phytophthora form swarm tracks that can easily spread through water and splashing soil particles.
The development is promoted by moist substrate and temperatures of 18 - 30 ° C / 64 - 86 °F.
Fusarium Solani
Another primary pathogen is Fusarium Solani.
The symptoms are similar to those of Phytophthora.
Both fungi first infect the roots, after which they can affect the stem foot.
The development of Fusarium Solani proceeds fastest at higher temperatures between 20 and 30 ° C / 68 - 86 °F.
Rhizoctonia solani
Rhizoctonia can infect both the roots and the stem foot.
Often the damage starts on the border between soil and air.
Here the stem is constricted so that plants fall over.
Seedlings in particular are very sensitive to this fungus. In contrast with Fusarium, Rhizoctonia develops best at a lower temperature (15 - 18 ° C / 59 - 64 °F).
Thielaviopsis basicola
This fungus is also called Chalara Elegans. Brown constricted spots can be seen on the roots. In the event of severe damage, a constriction can occur on the boundary between soil and air.
In this case, the infestation can be confused with a Rhizoctonia infection.
The leaf axles can also be browned, which can be confused with a Phytophthora attack.
The fungus grows well at temperatures of 25 - 28 ° C / 77 - 82 °F but can infect the plants more easily at temperatures of 15 - 20 ° C / 59 - 68 °F.
Problems usually arise during cool days.
Pythium
Pythium is a secondary fungus that can only affect weakened or very young plants.
At the roots affected by this fungus, the bark is detached from the vascular bundles.
Pythium develops optimally in wet conditions and at a temperature of 20 ° C / 68 °F.
Fluctuations in the EC also promote the development of Pythium.
All the above paragraphs show that there is not just 1 cause for root rot.
Even commercial growers sometimes don't know what causes root rot in their systems.
What they can do is have the fungus or rot analyzed. DNA analysis.
So when they know what disease they actually have, they can change the growing circumstances to prevent that specific disease; Lowering the temperature or perhaps making it higher, a more stable EC, making sure their feeding water is already on a higher temperature, etc.
Especially Pythium can be caused by what we call 'shock'. When changing the reservoir, the roots get for example much colder water as they were in before, or water with a different EC.
So, all this shows that there is not 1 cause and also not 1 solution for root rot.
All who say there is, are wrong and ignore science.
Some people are convinced that you have to keep the temperature of your reservoir below a certain point.
For example below 20°C / 68°F. Otherwise your roots will get all messy, brown, stinky.
I did some research about it already long time ago, and also visit commercial hydro growers regularly. Never could I find information about the claim for low temperatures.
On the contrary, most commercial growers agree that roots and plants develop best by temperatures higher then 20°C / 68°F.
But what about the root rot then?
I came across an interesting article. Not from some cannabis publication (who often don't understand science and biology and just repeat or misinterpretate what they read somewhere) but from a legitimate source.
The article is in Dutch, but Google Translate is my friend.
The cause of root rot is not always clear. An attack by, for example, Phytophthora can be mistaken for a Fusarium attack.
Causes of poor growth and symptoms usually start at the roots.
If the roots are in bad condition, this can lead to symptoms such as branch mortality and leaf spots in the aboveground parts.
A common problem is infestation by plant pathogenic fungi.
If these infect the roots, root rot often develops.
The roots can no longer absorb water and nutrients in severe rot. Plants will thus remain behind in growth, yellowing, withering and eventually dying off.
The symptoms that cause different fungi are not always easy to distinguish from each other.
Especially if the damage is at an advanced stage, it will be difficult to visually assess which fungus is the primary cause.
An attack by, for example, Phytophthora can be mistaken for a Fusarium attack.
A number of common fungi that can cause root rot are: Phytophthora, Fusarium solani, Rhizoctonia solani, Thielaviopsis basicola and Pythium.
The conditions under which these fungi can develop and infect the plant vary by species. Below is a short description of these fungi:
Phytophthora
This fungus is a primary pathogen. This means that it can infect healthy plants.
Phytophthora infects the roots after which it can cause rot in the stem base.
The spores germinate quickly at a low temperature shock caused by cold water.
Because of this, a Phytophthora infection often occurs during cold days / nights.
The spores of Phytophthora form swarm tracks that can easily spread through water and splashing soil particles.
The development is promoted by moist substrate and temperatures of 18 - 30 ° C / 64 - 86 °F.
Fusarium Solani
Another primary pathogen is Fusarium Solani.
The symptoms are similar to those of Phytophthora.
Both fungi first infect the roots, after which they can affect the stem foot.
The development of Fusarium Solani proceeds fastest at higher temperatures between 20 and 30 ° C / 68 - 86 °F.
Rhizoctonia solani
Rhizoctonia can infect both the roots and the stem foot.
Often the damage starts on the border between soil and air.
Here the stem is constricted so that plants fall over.
Seedlings in particular are very sensitive to this fungus. In contrast with Fusarium, Rhizoctonia develops best at a lower temperature (15 - 18 ° C / 59 - 64 °F).
Thielaviopsis basicola
This fungus is also called Chalara Elegans. Brown constricted spots can be seen on the roots. In the event of severe damage, a constriction can occur on the boundary between soil and air.
In this case, the infestation can be confused with a Rhizoctonia infection.
The leaf axles can also be browned, which can be confused with a Phytophthora attack.
The fungus grows well at temperatures of 25 - 28 ° C / 77 - 82 °F but can infect the plants more easily at temperatures of 15 - 20 ° C / 59 - 68 °F.
Problems usually arise during cool days.
Pythium
Pythium is a secondary fungus that can only affect weakened or very young plants.
At the roots affected by this fungus, the bark is detached from the vascular bundles.
Pythium develops optimally in wet conditions and at a temperature of 20 ° C / 68 °F.
Fluctuations in the EC also promote the development of Pythium.
All the above paragraphs show that there is not just 1 cause for root rot.
Even commercial growers sometimes don't know what causes root rot in their systems.
What they can do is have the fungus or rot analyzed. DNA analysis.
So when they know what disease they actually have, they can change the growing circumstances to prevent that specific disease; Lowering the temperature or perhaps making it higher, a more stable EC, making sure their feeding water is already on a higher temperature, etc.
Especially Pythium can be caused by what we call 'shock'. When changing the reservoir, the roots get for example much colder water as they were in before, or water with a different EC.
So, all this shows that there is not 1 cause and also not 1 solution for root rot.
All who say there is, are wrong and ignore science.
