Grow Mediums AFN Communal Autopot Test Summer 2018

[pop22]

Still waiting on my clay balls to come in

Not needed! Get growing!

 

[sniper]

Not needed! Get growing!

I didn't spend the money not to use them after a hateful email they sent me a new tracking number says they will be here this weekend

 

[Frank Nitty]

Ok, so my stomper is running its last leg of the race in its autopot, the toof has just started to run... Since the stomper will finish first, should I put the pot in the bathtub and flush it, or should I even bother?

 

[scally420]

Blue Cheese (dinafem).

 

[pop22]

don't bother, it really won't accomplish anything

Ok, so my stomper is running its last leg of the race in its autopot, the toof has just started to run... Since the stomper will finish first, should I put the pot in the bathtub and flush it, or should I even bother?

 

[Frank Nitty]

don't bother, it really won't accomplish anything

Thanks stranger

 

[Ripper]

Thanks stranger

Pop22 doesn’t believe there is any benefit to flushing.

 

[Tiny Bubbles]

Are any of the folks who use megacrop with their autopots using the sweet candy as well? Has this already been answered and I’m a stoned idiot who missed it somehow? (if yes my bad)

I’m thinking it would start to stink up the place or gunk up my lines? Or am I totally off on this one

 

[pop22]

My evaluation of megacrop has me following Greenleaf's advice, you don't need anything else! Mega has everything your plant needs. bloom boosters and "bud candy" are snakeoil , a waste of money.

And yes, it could plug up your lines. Keep a 30ml syringe handy, they are great for flushing your lines with! I just push some hot water through each line if it plugs, although my preventative is to keep a premade assembly of the tubing and fittings and I swap them out once a month, flush the previos set and use it again the next month. Takes 5 minutes total to change them and flush the previous set. I've had one clog that stopped flow to a pot in the last 2.5 years of using autopots. However, i check the soil for dryness every day, and if it feels dry, I check the valve reservoir to see if its dry. Just simple routine maintainance.

Are any of the folks who use megacrop with their autopots using the sweet candy as well? Has this already been answered and I’m a stoned idiot who missed it somehow? (if yes my bad)

I’m thinking it would start to stink up the place or gunk up my lines? Or am I totally off on this one

 

[hesgone13]

My evaluation of megacrop has me following Greenleaf's advice, you don't need anything else! Mega has everything your plant needs. bloom boosters and "bud candy" are snakeoil , a waste of money.

And yes, it could plug up your lines. Keep a 30ml syringe handy, they are great for flushing your lines with! I just push some hot water through each line if it plugs, although my preventative is to keep a premade assembly of the tubing and fittings and I swap them out once a month, flush the previos set and use it again the next month. Takes 5 minutes total to change them and flush the previous set. I've had one clog that stopped flow to a pot in the last 2.5 years of using autopots. However, i check the soil for dryness every day, and if it feels dry, I check the valve reservoir to see if its dry. Just simple routine maintainance.

Here is some more science on why flushing is a waste of time and resources!

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.

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.

‘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.


Here is a simplified overview of nutrient functions:

Nitrogen is needed to build chlorophyll, amino acids, and proteins. Phosphorus is necessary for photosynthesis and other growth processes. Potassium is utilized to form sugar and starch and to activate enzymes. Magnesium also plays a role in activating enzymes and is part of chlorophyll. Calcium is used during cell growth and division and is part of the cell wall. Sulfur is part of amino acids and proteins.

Plants also require trace elements, which include boron, chlorine, copper, iron, manganese, sodium, zinc, molybdenum, nickel, cobalt, and silicon.

Copper, iron, and manganese are used in photosynthesis. Molybdenum, nickel, and cobalt are necessary for the movement of nitrogen in the plant. Boron is important for reproduction, while chlorine stimulates root growth and development. Sodium benefits the movement of water within the plant and zinc is neeeded for enzymes and used in auxins (organic plant hormones). Finally, silicon helps to build tough cell walls for better heat and drought tolerance.


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 plant roots, 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.

Not all nutrient compounds are moveable within the plant.

1) N, P, K, Mg and S are considered mobile: they can move up and down the plant in both xylem and phloem.
Deficiency appears on old leaves first.

2) Ca, Fe, Zn, Mo, B, Cu, Mn are considered immobile: they only move up the plant in the xylem.
Deficiency appears on new leaves first.

Storage organelles:
Salts and organic metabolites can be stored in storage organelles. The most important storage organelle is the vacuole, which can contribute up to 90% of the cell volume. The majority of compounds found in the vacuole are sugars, polysaccharides, organic acids and proteins though.

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: usually plants use nitrogen to form plant proteins. Enzyme systems rapidly reduce nitrate-N (NO3-) to compounds that are used to build amino-nitrogen which is the basis for amino acids. Amino acids are building blocks for proteins, most of them are plant enzymes responsible for all the chemical changes important for plant growth.

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 unbalanced nutrition rather than an excess of nitrogen.

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 preharvest flushing.

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.