Define This !!! and Help me to save her ! :)

thefanfx said:

Hey fellows

I'm having issue with this decease on the pictures bellow
Short Description:
White Widow plant 36 days old
Perfect temperature 27 Celsius
Perfect Ventilation with 2 fans
Soil from BioBizz 14 liters inside the pot with pH 6.4
Watering once per 48h 800ml pure water
Nutrition till now only 2 times x 0.5mg per 2 liters of water from Canna Bio Flores
Air Pot - 10 liters

The Decease:
Brownish spots . shown first on my top big leaves edges , then spread to almost all top big leaves and some little once too
The decease makes the leaves dry in 3 days after the spots are shown and if you touch the leaf it falls apart totally dry (see pics)[URL=https://www.icmag.com/ic/picture.php?albumid=40234&pictureid=951921&thumb=1]View Image[/URL] [URL=https://www.icmag.com/ic/picture.php?albumid=40234&pictureid=951922&thumb=1]View Image[/URL] [URL=https://www.icmag.com/ic/picture.php?albumid=40234&pictureid=951923&thumb=1]View Image[/URL] [URL=https://www.icmag.com/ic/picture.php?albumid=40234&pictureid=951924&thumb=1]View Image[/URL] [URL=https://www.icmag.com/ic/picture.php?albumid=40234&pictureid=951925&thumb=1]View Image[/URL]

Please help me to define this , no idea why it appears , it started from pure green and healthy plant before 4 days and now it almost destroyed every leaf which is affected , there were no critical changes in environment or any other

P.S: I suspect Ca-Mag deficiency , but it sound impossible with this amount of soil and nutrition ... dunno try to help

Full Album here:
https://www.icmag.com/ic/album.php?albumid=40234

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joe fresh said:

Potassium Deficiency

The onset of potassium deficiency is generally characterized by a marginal chlorosis progressing into a dry leathery tan scorch on recently matured leaves. This is followed by increasing interveinal scorching and/or necrosis progressing from the leaf edge to the midrib as the stress increases. As the deficiency progresses, most of the interveinal area becomes necrotic, the veins remain green and the leaves tend to curl and crinkle. In some plant such as legumes and potato, the initial symptom of deficiency is white speckling or freckling of the leaf blades. In contrast to nitrogen deficiency, chlorosis is irreversible in potassium deficiency, even if potassium is given to the plants. Because potassium is very mobile within the plant, symptoms only develop on young leaves in the case of extreme deficiency. Potassium deficiency can be greatly alleviated in the presence of sodium but the resulting sodium-rich plants are much more succulent than a high potassium plant. In some plants over 90% of the required potassium can be replaced with sodium without any reduction in growth.

Potassium deficiency, also known as potash deficiency, is a plant disorder that is most common on light, sandy soils, because potassium ions (K+) are highly soluble and will easily leach from soils without colloids.[1] Potassium deficiency is also common in chalky or peaty soils with a low clay content. It is also found on heavy clays with a poor structure.

Potassium plays a big role as well. Having good amounts of potassium in your plants helps in having sturdy and thick stems, disease-resistance, water respiration, as well aids in photosynthesis. Potassium is also found in the whole plant. It is necessary for all activities having to do with water transportation. Potassium is necessary for all stages of growth, especially important in the development of Buds.

Having to little of Potassium in your plants causes the plants leaves to show retarded growth and show a scorched tip and edges around the leaves. Plants may stretch and your branches can be easily broken or weak. Don’t get this deficiency confused with iron, because it almost acts like iron but to tell the difference in the two is: for potassium the tips of the leaves curl and the edges burn and die. Older leaves may show a red color and leaves could curl upwards. Dead patches (Necrosis) can happen on the margins of larger fan leaves thus, the leaves will eventually die off and turn brown. The Older leaves will show different patches of color (mottle) and turn yellow between the veins, following by whole leaves that turn dark yellow and die. The plants overall growth slows down, mostly when they are in vegetative stage. To little amount of potassium also slows the growth of buds during flowering stages. Dark edges will appear around the edges of the leaf when the deficiency is starting to happen. When your Relative humidity is low, you can almost bet your going to soon get a potassium deficiency from your plants perspiration.
Potassium can get poorly absorbed when having too much Calcium or ammonium nitrogen, and maybe cold weather. Having to much sodium (Na) causes potassium to be displaced. SO keep those in mind… Parts affected by a Potassium Deficiency are: older leaves and leaf margins.


When you have too much Potassium in your soil, it can lead to big troubles, like salt damage and acid fixation of the root system, as well as too much potassium can cause a calcium deficiency. Your fan leaves will show like a light to a dark yellow to whitish color in between the veins. Due to a molecular imbalance, potassium toxicity can cause a reduced uptake and lead to the deficiencies of Mg, and in some cases, Ca. Also leads to the other nutrients to not be absorbed properly leading to lots of other deficiency such as: magnesium, manganese, zinc and iron and can cause problems with calcium as well.



Problems with Potassium being locked out by PH troubles
Soils with excessive Leeching and High ph soils and or water.Soils that are potassium fixated. An excess of kitchen salts (sodium) in the root system/enviroment.


Soil

Potassium gets locked out of soil growing at ph levels of 4.0-5.5
Potassium is absorbed best in soil at a ph level of 6.0-9.5. (Wouldn’t recommend having a ph of over 7.0 in soil) anything out of the ranges listed will contribute to a Potassium deficiency.


Hydro and Soil less Mediums

Potassium gets locked out of Hydro and Soil less Mediums at ph levels of 4.0-4.5, 6.0-6.5.
Potassium is absorbed best in Hydro and Soil less Mediums at ph levels of 4.7-5.3, 6.7-8.5. (Wouldn’t recommend having a ph over 6.5 in hydro and soil less mediums.) Best range for hydro and soil less mediums is 5.0 to 6.0. Anything out of the ranges listed will contribute to a potassium deficiency.

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