REMINDER for those who dont FLUSH

i just found out the difference between a zero-day flush and a two week flush.

wow.

for those who dont know if they should flush their plants, or think they dont have to... yes, you must.

just a friendly reminder, no response needed hopefully this will land in searches along with the others heh. just tryin to keep the green good out there- i know this isnt news!

What if your growing organic? I mean bat shit and blood meal are still gonna be there. You can't wash that stuff away....or can you?

You can flush most of the available nutes out, and it is absolutely a must in any soil grow. Some hydro chaps can run real light and go no flush, but I need a full flush on my girls. And I am worth the effort, aren't you?
H

Taken from the OG Online Grow Tutorial.

If you have been growing the plant on organic nutrients then there is seldom a need to clear the plant since it has not taken up any foul tasting chemical nutrients. The extra N stored in the foliage will have been used up as part of the natural process of final budding.

Click to expand...

The organics will still be alive and left behind (hopefully) by the time you harvest, but you can still flush most of the available N, P, and K out of the soil which has allready broken down from it's original source (the guanos, kelp, and meals which will still be breaking down in the soil).

Tell us twojoints, what were some of the fertilizers you had used on her recently? There's nothing harsher than weed that was hit with some fish emulsion too late in flower.

I can't seem to find it with my searches so i'll ask here...

Will flushing ruin the quality of my seeds by stunting them at their final stages of development?
I'm mainly concerned about the lack of available nitrogen during flushing, but to be honest, I forgot which nutrients are key to seed production.
Should I just skip the flush since I'm more concerned about the seeds than the bud?

the conditions are:

dwc
modified lucas (closer to 10mL micro, 20-22mL bloom per gallon)
~8 week strain
pollinated from week 1 to week 2/3 of flowering
currently almost at the end of week 6
planning for a 2 week flush

thanks for any help and sorry if this is a hijack (ill just delete it if you think it is)

organics can be flushed.

Yes it really is a lot smoother after a flush if I don't it'll be harsh. Fish Emulsion PBP bloom & PK-13/14

Rosy Cheeks said:

I've been an indoor grower now for approximately 7 years, and was an outdoor grower for about 11 years before that. I'm still very iffy about flushing, mainly because I concider that my outdoor crops were superior in taste and crop quality, and they were never flushed.

As to indoor growing, cutting out the nitrogen before harvest seems to improve taste somewhat and the buds burn better. But, IMO, the effect is inferior to what a good cure will do to the crop quality (so when ethereal says that cashcropper bud is less smokeable because it wasn't flushed, I say that it is probably less smokeable because it didn't get a 2 months + cure).

The notion that plants 'stock' excessive nutrients doesn't really wash. Plants don't stock nutrients in the same sense as humans stock fat, they take what they need to grow exponentially and transform it into increased root, stem, leaf and flower growth. Plants can overfeed, but generally when one or several grow factors - such as light output or root space - do not allow them to grow at will. Most overfert symptomes are not due to overfed plants, but excessive nutrient concentrations in the medium, which dehydrates the roots.

So, why slowly starve your plants to death two weeks before harvest? The late/end flower cycle is a period when Cannabis can put on lots of extra weight - in terms of bud mass and resin production - in a last attempt to pollinate. In 2005, Dr. Paul Hornby (a Ph.D and Cannabis researcher working for Advanced Nutrients) tested THC content in indoor cultivated plants, and found that plants that peaked in THC content in week 6 of flower, decreased in THC content during week 7 and 8 (or rather, vegetal mass increased but cannabinoid production decreased, so the cannabinoid content was diluted into a larger vegetal mass) - because the plants were flushed.

So, to sum it up, your often looking at a lower yield thanks to starving your plants, and if Dr. Hornby's results are correct, a lower potency as well.

Whether you think it's worth it to get a bud that tastes and burn better is up to you, but you can get that anyway by decreasing N significally during end flower to almost nothing right before harvest, and give the buds a proper cure.

Click to expand...

Rosy Cheeks said:

Haps, if you check out Advanced Nutrients' nutrient calculator online, what does it recommend for the last week of flower?

http://www.advancednutrients.com/nutcalc3public/

A flush. I equally have General Hydroponics, BioBizz and Plagron's nutrient charts in front of me, and they all recommend a flush in the last week.
So that kind of blow your theory to smithereens, doesn't it?

And why automatically assume that Dr. Hornby is luying, because he's working for someone? Do you luy because you work for someone? I respect his scientific integrity and will assume he's telling the truth, until convincing indications leads me to believe otherwise. Do you have any of those?

His study (and others') did not "prove" you shouldn't flush, the study showed that THC ratios dropped during the weeks of flush, because you cut out all the nutrients to the plants. I see nothing shocking about it - unless you're a convinced flusher that doesn't like to hear that potency drops because of it. Now we need more research to either corroborate or contradict these results.
Dr. Hornby by the way indicated that his research group is working on trying to isolate what nutrients will continue to produce resin (cannabinoids) and which doesn't, so that you can administer only those needed while still flushing the plants, which means he believes in that a flush does have a positive effect on the smokability of the crop.

Click to expand...

Flushing is not the "end all be all" of growing.

Outdoors, the plants use up all the nutrients their roots can find and process, well before harvest season, and you can read the leaf to see what it runs out of, as they grow, that is why outdoors weed tastes good without flushing. And like everything else, there are exceptions to that generalization.

Unflushed weed CAN taste OK and be good smoke, but it will never be as good as flushed is and I say that after many crops indoors testing a variety of flush/non flush/partial flush methods and smoking the results. It ain't a rule, but it is cool.
H

I havent flushed and I have great reviews on my weed. Maybe the average joe doesnt know better. I grow hydro/non organic

And like everything else, there are exceptions to that generalization.

Click to expand...

Maybe flushing could also get an exception here and there? For example, if the plants get severe tip burn, because they didn't want to eat as much toward the end and was fed heavily anyway, then it is probably a good idea to flush. However, if the grower listens to the plant and reduces the feeding amounts accordingly to the plants finishing needs, a flush might not be as essential. Basically there are more options than just full dose feeding all the way or no feeding at all towards the end.

Now if people got as excited about curing as they do about flushing... hmm...

I grow organic and i use the "Shitz " and molasses like crazy, all i have to do is flush for a week and thats it!

edit: and using the Bio-Bizz line of nutes, im happy with them.

I grow in almost 100% CoCo Coir, and I always flush one week, then put the in the dark with nothing for 2 days or so before chopping. Works great.

Oh, my flush is two-part:
1st flush--3X the volume of the container in Sugar Water or Clearex
2nd--2X the volume of the container in plain water
3rd (if coco is dry again and its needed)--1X the volume of the container in plain water

I actually just recently saw the first real evidence of flushing being effective. I've always done it, but if you harvest like 10 days after or so (I've) never really noticed any difference. However, I flushed my most recent plant, watered it for a week maybe more, went away for a week and come back to see it looking like fall in my closet. It was really yellow but the buds looked nice still. I am now assured that flushing is good!!

flushing outdoors isnt needed because of the seemingly endless supply of soil for the plants to grow in. container growing of canibis and flushing should be done chem ferts shoudl be stopped 14 days before chop and plain PH'd water used in every watering. organic liquid ferts stoped 10 days before i stop guanos 4 days before, best way to tell if plant is flushed and ready for chop is take a large fan leaf stem and all. now chew stem if it tastes bitter needs another water or 2 if it taste like water and ready for salad then plant is properly flushed and ready for chop.. also the water draining will be clear least mine is during my flushing process. most bud growen indoors if not flushed will most likely be harsh not burn or smell right and the ash will be very dark. properly flushed plant isnt harsh will some times taste like water untill a cure and the ash burns light in color.

flush forsure

flush at least a week please

Here is an old OG FAQ may be of some help

Here is an old OG FAQ may be of some help

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A critical look at preharvest flushing
Added by: snoofer Last edited by: vaaran Viewed: 460 times Rated by 32 users: 9.16/10
Contributed by: vaaran
Submitted: November 15th, 2004

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.

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 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.

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 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.

http://www.sirinet.net

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.

http://generalhorticulture.tamu.edu

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.

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: 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.

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 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.
Last modified: 00:07 - Feb 17, 2005 This could help me decide. I've still got a little time to decide.

If flushing is not an option curing will be necessary.