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Metrop Hydroponics growinfo, plant growth troubles:

 

 

Purple stems:

 

Sometimes you see purple stems, on grower’s plants.
This comes from one thing only, shortage of phosphorus.
Phosphorus is the 2nd most important building stone of a plant and a shortage of this will result in another chemical reaction from the nitrogen in the plant.

The causes of the shortage of the phosphorus in the plant could be:

 

1) COLD:
With a temperature under 20 degrees celcius Phosphorus moves less in the plant and with a temperature under 17 degrees Celcius stops moving all together.
The Phosphorus stops moving which creates a shortage. The plant almost does not grow any more either with a temp under 17degrees Celcius.
Note: also at night a plant grows and therefore the temp should not be below 20 degrees. Every time it reaches a lower temperature it will reduce your harvest.

 

2) PH TOO HIGH:
If the PH in the medium reaches 6.0 or above phosphorus will be absorbed less.
Does it reach 6.5 or higher, it will almost not be absorbed at all.

 

3) WRONG FOOD:
Phosphorus comes in different qualities, this has to do with the origin of the nutrient (where phosphorus is made out of).
The quality determines the absorption, the concentration and the mix ability.
Most food suppliers use cheap phosphorus thru which no high concentrations are possible and it will attach to other elements.
Like: crystallizing, crusting on the medium.
Shortages are supplemented with a phosphoric acid to be used a PH-.

A shortage of phosphorus is often seen if the grower uses nitric acid as a PH- with the mother plants.
A certain competitor sells this as a growth PH-.
This is completely wrong, especially if you use the plant food from the same competitor.


 

 

Light leafs and burning:

 

Leafs that both burn and are light of color, is a common problem.
Most common cause: PH too high or too low.

If the PH in a medium reaches for instance, under 5.2 or above 6.0 a lot of salts will not be absorbed by the plant anymore.
The bigger the difference from the ideal PH, the less absorption.
The plant will have a shortage and the leafs become lighter of color.
Although all this time the plant was fed and the concentration of nutrient salts piled up. The balance is gone ,so water will be retracted from the leafs, back into the medium. This is called burning.

The first warning for this is that the leaf will curl up, or turning yellow from the leaf edge.
The plant notices the change in balance with the medium and will as a reaction to this, close its skin mouths on the outside and under the leaf.

 

 

 

The plant becomes hard, but will not grow:

 

A  common problem with inside vegetation is that the fruit start will harden but not grow. Growers spend a fortune on suction and ventilation systems, but forget that what goes out needs to come back in.
Often the inlet of air is too small against the suction or no inlet of air at all, but a small opening some where.
This way you create a big under pressure and the plants will gasp for fresh air (CO2).
Would you crack the door for a week, the plants will grow twice as big after this week.
Just the right air inlet or a bigger inlet will solve this problem.

 

 

 

Fruit start has airy construction:

 

Shortage of heat.
Growers sometimes are growing volume but without contents.
This happens in climates where the temperature around the leaf is 32 degrees Celcius or higher. Or where the air is very thin.
The plant will kind of grow to the outside………
Also when the food intake is stagnated, the plant simply needs more then is available and the plant will increase in volume.
All of this also depends on the genetics of the plant of course, one plant will be more sensitive for this then another.
If the PH is good, and the EC for watering low, you can up the EC from the watering.
If the temperature is too low, simply raise it some.
If the light is too weak, strengthen it.

 

 

 

Curling of the leafs:

 

Growers can see their leafs, mostly on the side and on top, curl.
Curling of the leavesSkin mouths with which the plants breath are on the bottom of the leaf.
For the absorption of water and nutrients, these skin mouths need to evaporate water. If there is a disruption thru which the plant will evaporate less water, then some of the skin mouths will close on the outside of the leaf. The leaf edges will then curl. The bigger the disruption, the more mouths will close, the more the leaf will curl.


Causes of disruption could be:

1) Too much evaporation under the leaf.
Thru heat, low humidity or a blower that blows too hard, the plant will evaporate more then he can absorb.

2) Too much salts in the medium by over feeding or a wrong PH.
The medium will want to compensate the in balance  of salts in the plant and in the medium by holding water or even retract it from the leafs (leaf burning).

3) The plant will receive less or no water and will close it’s mouths in order not to lose more water. Air shortage in the medium will hinder the movement of the elements.


Copyright Metrop Hydroponics 2004.