Le rincage

[charbs]

bonsoir
jvous laisse le lien d'une discution sur le fcf concernant le rincage.
jvoulais juste savoir ce que vous pensiez du discours d'aeroman pour les autres posteurs aucun interets.

http://www.fcf.cannaweb.ch/fcf/viewtopi ... 20&start=0

merci et bonne soiree

[homer]

salut charbs

Je viens de lire liens j'ai juste un chose a dire

Qu'il revoit son rinçage

A++

[charbs]

erf homer sa fait pas avancer le sujet
tu es donc contre le ptit aeroman mais se ki m'interressait c'etait de lire vos arguments.
Le FCF est un parking a boulets, tout comme le chat de LMV qui est un garage de pseudo
chanvri du meme avis alors ?

[Che Bleu]

Pre harvest flushing is a controversial topic. Flushing is supposed to improve taste of the final bud by either giving only pure water, clearing solutions or extensive flushing for the last 7-14 days of flowering. While many growers claim a positive effect, others deny any positive influence or even suggest reduced yield and quality.

The theory of pre harvest flushing is to remove nutrients from the grow medium/root zone. A lack of nutrients creates a deficiency, forcing the plant to translocate and use up its internal nutrient compounds.

Nutrient fundamentals and uptake:

The nutrient uptake process is explained in this faq.

A good read about plant nutrition can be found here:

Fertilizers are materials that contain nutrients required by plants. In some cases, organic materials such as manures and plant residues can supply some or all the nutrients required by plants. In other cases mineral nutrition aids or completely replaces the organic nutrient supply. Until recently it was common thought that all nutrients are absorbed by plant roots as ions of mineral elements. However in newer studies more and more evidence emerged that additionally plant roots are capable of taking up complex organic molecules like amino acids directly thus bypassing the mineralization process.

The major nutrient uptake processes are:

1) Active transport mechanism into root hairs (the plant has to put energy in it, ATP driven) which is selective to some degree. This is one way the plant (being immobile) can adjust to the environment.

2) Passive transport (diffusion) through symplast to endodermis.

http://www.biol.sc.edu/courses/bio102/f99-3637.html

http://www.hort.wisc.edu/cran/Publications/2001 Proceedings/min_nutr.pdf

The claim only ‘chemical’ ferted plants need to be flushed should be taken with a grain of salt. Organic and synthetic ferted plants take up mineral ions alike, probably to a different degree though. Many influences play key roles in the taste and flavor of the final bud, like the nutrition balance and strength throughout the entire life cycle of the plant, the drying and curing process and other environmental conditions.

3) Active transport mechanism of organic molecules into root hairs via endocytosis.

http://acd.ucar.edu/~eholland/encyc6.html

Here is a simplified overview of nutrient functions:

Nitrogen is part of chlorophyll, amino acids, and proteins. Phosphorus is used in photosynthesis and other growth processes. Potassium is used to form sugar and starch and to activate enzymes. Calcium is utilized during cell growth and division and makes up part of the cell wall. Magnesium also activates enzymes and is part of chlorophyll. Sulfur makes up amino acids and proteins. The plants also need trace elements, which include boron, chlorine, copper, iron, manganese, sodium, zinc, molybdenum, nickel, cobalt, and silicon. Copper, iron, and manganese play parts in photosynthesis. Molybdenum, nickel, and cobalt are used in the movement of nitrogen in the plant. Boron affects reproduction, while chlorine aids in root growth and development. Sodium aids the movement of water within the plant and zinc is part of enzymes and used in auxins, which are basically organic plant hormones. Finally, silicon makes tough cell walls, which enhance heat and drought tolerance.

http://www.sidwell.edu

You can get an idea from this how closely all the essential elements are involved in the many metabolic processes within the plant, often relying on each other.

Nutrient movement and mobility inside the plant:

Besides endocytosis, there are two major pathways inside the plant, the xylem and the phloem. When water and minerals are absorbed by the roots of a plant, these substances must be transported up to the plant's stems and leaves for photosynthesis and further metabolic processes. This upward transport happens in the xylem. While the xylem is able to transport organic compounds, the phloem is much more adapted to do so.

The organic compounds thus originating in the leaves have to be moved throughout the plant, upwards and downwards, to where they are needed. This transport happens in the phloem. Compounds that are moving through the phloem are mostly:
Sugars as sugary saps, organic nitrogen compounds (amino acids and amides, ureides and legumes), hormones and proteins.

http://www.sirinet.net

Not all nutrient compounds are moveable within the plant.

Two directions of movement within plants:
1) acropetal - means towards the apex; transport up the in xylem
2) basipetal - means towards the base; transport down in the phloem

Two classifications of nutrient mobility:
1) Mobile - moves both up and down the plant by both acropetal and basipetal transport (in both the xylem and the phloem).
Deficiency appears on older leaves first. N, P, K, Mg, S

2) Immobile - moves up the plant by only acropetal (in the xylem) transport. Deficiency appears on new leaves first. Ca, Fe, Zn, Mo, B, Cu, Mn

http://generalhorticulture.tamu.edu

Storage organelles:

When the plant receives excessive nutrition or is under serious stress, nutrient compounds can be stored in storage organelles. The most important storage organelle is the vacuol, which can occupy up to 90% of the cell volume. Vacuoles play important metabolic roles in addition to growth.

These roles include, among others, the following.

(1) Storage: Vacuoles can serve as storage organelles for sugars, polysaccharides, organic acids and proteins. Most of the flavors of fruits and vegetables are due to the compounds stored in the vacuols. When needed, these primary metabolites can be retrieved from the vacuole and utilized in metabolic pathways.

(2) Toxic avoidance: Being immobile, plants cannot escape exposure to toxic elements in the environment by moving to another location. Nor do plants have an excretory system for the elimination of such substances. By accumulating heavy metals, such as cadmium and sodium the vacuole can be viewed as a micro-kidney inside each plant cell, filtering and sequestering potentially toxic ions from the cytosol. The same thing happens to nutrient compounds when they reach toxic levels.

http://jeb.biologists.org.pdf

Translocation:

Now that the basics are explained, we can take a look at the translocation process. It should be already clear that only mobile elements can be translocated through the phloem. Immobile elements cant be translocated and are not more available to the plant for further metabolic processes and new plant growth.

Since flushing (in theory) induces a nutrient deficiency in the rootzone, the translocation process aids in the plants survival. Translocation is transportation of assimilates through the phloem from source (a net exporter of assimilate) to sink (a net importer of assimilate). Sources are mostly mature fan leaves and sinks are mostly apical meristems, lateral meristem, fruit, seed and developing leaves etc.

You can see this by the yellowing and later dying of the mature fan leaves from the second day on after flushing started. Developing leaves, bud leaves and calyxes don’t serve as sources, they are sinks. Changes in those plant parts are due to the deficient immobile elements which start to indicate on new growth first.

Unfortunately, several metabolic processes are unable to take place anymore since other elements needed are no longer available (the immobile ones). This includes processes where nitrogen and phosphorus, which have likely the most impact on taste, are involved.

For example nitrogen: under normal growing conditions plants use nitrogen to form plant proteins. With sufficient light as a source of energy, enzyme systems in green plants rapidly reduce nitrate-N (NO3-) to intermediate compounds that are subsequently converted into amino-nitrogen.
Organic acids arise from carbohydrate metabolism in combination with the amino-nitrogen to yield amino acids in the plants. The amino acids are building blocks for proteins.
Most of the proteins in plants are enzymes, catalysts that carry out all of the chemical changes involved in plant growth. There is at least one enzyme specifically responsible for every step in respiration, photosynthesis, gene replication, information processing and building cell structure.
Sulfur and calcium among others have major roles in production and activating of proteins, thereby decreasing nitrate within the plant. Excess nitrate within the plant may result from too little of some other plant nutrient rather than an excess of nitrogen.

http://muextension.missouri.edu

Summary:

Preharvest flushing puts the plant(s) under serious stress. The plant has to deal with nutrient deficiencies in a very important part of its cycle. Strong changes in the amount of dissolved substances in the root-zone stress the roots, possibly to the point of direct physical damage to them. Many immobile elements are no more available for further metabolic processes. We are loosing the fan leaves and damage will show likely on new growth as well.

The grower should react in an educated way to the plant needs. Excessive, deficient or unbalanced levels should be avoided regardless the nutrient source. Nutrient levels should be gradually adjusted to the lesser needs in later flowering. Stress factors should be limited as far as possible. If that is accomplished throughout the entire life cycle, there shouldn’t be any excessive nutrient compounds in the plants tissue. It doesn’t sound likely to the author that you can correct growing errors (significant lower mobile nutrient compound levels) with a 7-14 days preharvest flush.

Drying and curing (when done right) on the other hand have proved (In many studies) to have a major impact on taste and flavour, by breaking down chlorophylls and converting starches into sugars. Most attributes blamed on unflushed buds may be the result of unbalanced nutrition and/or overfert and unproper drying/curing.

[Che Bleu]

Des que j'ai un moment je m'y mets, mais vu le pavé et mon emploi du temps actuel va falloir patienter un moment

[charbs]

merci
je pensais la meme chose pour avoir fait avec rincage en hydro et sans.
et au vue de se qu'a ecrit aeroman sa me confortait (che pas si sa se dit) dans mon opinion.
en fait une plante ne pompe quasiment rien en eau ?

[Anonymous]

+1
avec une bonne gestion de l'engrais et une bonne connaissance de la genetique,pas besoin de rincage,au pire on peux descendre l'ec à 0.8 la dernière semaine

[Che Bleu]

D'facons , y a pas de secret, l'étape cruciale, c'est le sechage .

[MaxHouse]

Qu'en j'allais en Hollande y'a quelques années, a ce qu'il parait ils faisait des rinçages ou juste avant avec une espece de melange de jus de fruit type jus d'orange & pamplemousse pressé au pH corrigé pour adoucir le gout de la weed..

j'ai jamais osé le faire.....

[Dr Alimentado]

Chanvri, il faut, amha, également retenir que ce sont généralement les personnes qui surfert qui ont le plus recours au flush, et qui defendent le rincage (comme moi )
MErci pour ce ptit bout de text qui me convainc sur le champs... mais je fairais quand même des test with and without de temps en temps.. .des fois que...