Ready for flush?

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I am leaning on the disagree side but am also willing to listen and learn. I Do Know... I have grown stuff that at the end of a smoked bowl there is a black ball of hard yuk that needs tapped out and grown other bud that I flushed and when you were done smoking it there is light colored grey matter with basically no mass/weight. - ????
 
Nothing to do with my beliefs, have mute burn? Flush. It stops it, period. May not flush nutes out of plant, (read advanced nutrients piece on how Faultless Finish works) but it does wash them out of the dirt. Does that do any good? I feel any benefit to growth is liable to affect yield every time. I see stopping the burn as a "benefit" so I do it, so will continue.

Bubba
 
Salt buildup is in the soil causes the plant uptake problems. Flushing the salt out of your soil will allow the plant to be able uptake properly. Flushing does not remove ferts from your plant. Its not a straw that if it stops sucking up nutes shit drains out. The ferts remain in the plant material and flushing will not remove it. Guess you could starve your plant the last 3 or 4 weeks where it cant uptake any ferts but it wont remove anything thats still in the plant that the plant hasnt used. Dont believe me ask a Botanist.
The only thing i can see flushing do is clean the soil to where the plant cant find any nutes to use which to me makes no since to stop your plant from swelling up as much as possible before chop. I have smoked weed they claimed to flush and it tasted like fking dank. I couldnt see what the difference is.
Anyway. To each his own. Thats what freedom is all about.
Exactly.

Bubba
 
Isn't one of the reason for ratty fans around harvest is plant "consuming" itself from lack of nutes in soil? Huh, maybe those nutes don't flush out, but they still get used right? Otherwise what is with the argument to fertilize right up to harvest? You aren't adding those for nothing are you? In just thinking out loud.

Flushing is done by people who grow pot. Some people who grow pot do not have a complete understanding of the process. There are different reasons to flush. No maybe you can't flush nutes out, but if you don't give more, only give water. Plant uses up available nutes and starts consuming self....did not you lower amount of nutes in plant?


Bubba
 
Good reads. Then a question and "not argument".. How are you non flushers coming out with the hard black VS the soft light ash thing when you have smoked a bowl etc.? Maybe I was feeding too much. And really if you read, when it was discussing the whole osmosis thing as to overfeeding - if I read it right, you are actually poisoning the soil and not the plant with the whole reverse osmosis thing. - I gotta check in at work.. BRB
 
My weed burns just fine. Tastes great.

Also many nutrients are used up very quickly, and are needed at end stages. Like B Vitamines, which are not stored in the plant. Same for the human body. B vitamines must be supplied daily, or you will quickly have a deficiency. I cut back the nutrients by 50% the last 2 weeks.
People dont flush in hydro either. Only reason to flush would be if you have to much salt buildup in the soil, and is causing problems.


As you can see in the graph (copied directly from the study) each of the 6 different combinations of fertilizer and flushing showed only the tiniest differences which are well within the margin of error for a test like this. Essentially this means the different flushing methods had no measurable difference from the not-flushed control.

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Sales expression that I used to preach to my salesmen......."The longest distance berween an opening and a close is a SHORTCUT!!". JOSE Cervantes would roll over in his grave watching the new generation of growers finding ways to taking shortcuts.
 
Like politics....no body has changed their mind as far as I can tell....the conversation continues.....
Well, next go round ( I tend to do one strain at the time) I will do one without flushing, and give nutes to the end on a plant. I will not think it much of a risk, as several here do it.

I also want to try a dry trim, which I have never done as well. Who knows? Maybe I will change up.like the thread on "How long do you hold hits in" old habits die hard. If something works, it's hard to risk all the grow time on "unknowns"......but, no learning occurs without experimentation and trying things either. Plus, experienced folk here have made these ways work, so even less risk, right right?

Bubba
 
Hmmm what about a hydro set up in a toilet. Pour nutes in back of tank, plants in the bowl. Hell I got 4 bathrooms....flushing simplified! Lol

Bubba
 
What I find funny is we both use chemicals.....we flush primarily to remove salt build up which occurs with chemical nutes. Face it outdoor growers don't/can't flush. No need to flush with organic nutes. So there is no need to argue. Only chemical users need to flush and from what I see that is the way it is.
 
Yup. Don't be mind trying stuff if I can adapt something to indoor. Wish I had the big remote place to grow trees outside, but right now I am in the suburbs.

Bubba
 
IMPACT OF DIFFERENT FLUSHING TIMES ON QUALITY AND TASTE IN CANNABIS SATIVA L.
Data presented by: Stephanie Wedryk, PhD, Director of R&D at Rx Green Technologies Taylor Wall, Research Operations Lead at Rx Green Technologies Ryan Bennett, Research Associate at Rx Green Technologies

SUMMARY
Rx Green Technologies evaluated the effects of different flushing times on chemical profile, flavor, and smoking characteristics in Cannabis flower.
  • Flushing periods of 14, 10, 7 and 0 days were imposed on Cherry Diesel.
  • No differences were detected between flush treatments for yield, potency, or terpenes.
  • Analysis of mineral content of leaves indicated small changes in content of iron and zinc.
  • Taste test panelists tended to prefer flower flushed for 0 days.
INTRODUCTION
Taste and combustion qualities of Cannabis are dependent on the chemical characteristics of the flower. These chemical characteristics can be influenced by management practices during the growing cycle. For this reason, many Cannabis growers implement a flushing period where only water is fed to plants in the final days to weeks before harvest. While many cultivators attest to the effects of a flush, no scientific studies have been conducted to validate this practice. Rx Green Technologies has undertaken a first of its kind study to determine the influence of different flushing times on the chemical profile, flavor, and combustion characteristics of Cannabis flower.

MATERIALS AND METHODS
Cannabis variety Cherry Diesel (Cherry OG x Turbo Diesel) was grown at the Rx Green Technologies R&D Facility using Rx Green Technologies nutrients and Clean Coco. Grow A, Grow B and E-Plus were fed during the vegetative stage and Bloom A, Bloom B, E-Plus, and Bulk were fed during the flowering cycle. The first flushing period began 14 days before harvest. The other flushing periods were ten, seven, and zero days before harvest. Each flushing period was tested on 12 different Cherry Diesel plants divided into four different groups (replications) spread evenly across the flowering room tables. Flower and fan leaf samples were collected from each flushing treatment the first day of flush and the day before harvest to quantify concentrations of essential plant nutrients. After harvest, trial plants were cured before determining final trimmed flower weight, terpene and THC concentrations. Trim was evaluated by an extractor for THC, yield, and appearance of the extract or “wax”.
To determine smoking flavor and characteristics, samples of each flushing period were distributed to Cannabis industry experts in a blind taste test. Each participant received one sample of each flushing time without knowledge of its treatment. Participants were asked about their personal Cannabis flavor preferences before tasting. After tasting, participants were asked to rate the sample for flavor, harshness of smoke, and color of ash.

Data collected during the course of the trial were analyzed statistically to determine whether flushing times affected smoking quality, flower weight, or chemical characteristics of Cannabis. Statistical analysis of data allows us to quantify whether differences in the numbers are due to the treatments imposed or are results of the natural variations observed when growing plants.

RESULTS AND DISCUSSION
Visual differences in fan leaves between flushing times were apparent the day before harvest. Plants flushed for ten or 14 days had leaves that were more yellow, necrotic and dry than plants flushed for zero or seven days (Figure 1a-d). The color of the 14 and ten day flushed leaves indicates a greater breakdown of chlorophyll in the plant, leading to reduced greenness
Figure1.png


Figure 1. Fan leaves collected from Cherry Diesel plants the day before harvest. Flushing times depicted are (a) 14 days, (b) 10 days, (c) 7 days, and (d) 0 days.

Yield, THC, and Terpenes
The flower weight, THC and terpene content of cured flower were determined for each flushing period. The data were analyzed statistically to determine whether the numerical differences in the data were due to the treatment. Overall, there were no significant differences between treatments for flower weight, THC or terpene content (Figure 2a-c) (P < 0.05). Flower weight per plant averaged 97.3 g and THC content averaged 21.9%. The dominant terpenes in the flower were beta-myrcene, beta-caryophyllene, and terpinolene, giving the flower an earthy and spicy smell (Figure 2c). Overall, flushing times did not impact flower weight, THC, or terpenes in Cherry Diesel.
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Rx Green Technologies recently looked into the cannabis cultivation practice of flushing plants with water directly prior to harvest, which cannabis cultivators have long thought improves cannabis quality and flavor." data-reactid="18" type="text" data-xf-p="1" style="box-sizing: border-box; color: rgb(20, 20, 20); font-family: "Segoe UI", "Helvetica Neue", Helvetica, Roboto, Oxygen, Ubuntu, Cantarell, "Fira Sans", "Droid Sans", sans-serif; background-color: rgb(239, 243, 227.
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and more:
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Figure 2. Flower weight (a), THC (b) and terpene content (c) for Cherry Diesel flushed for 14, 10, 7 or 0 days before harvest. Significant differences are indicated at the 0.05 probability level.

Mineral Content of Flowers at Harvest
Flower samples taken the day before harvest were analyzed for content of essential plant nutrients. Overall, there was no significant change in the mineral content of flower as a result of different flushing treatments (Figure 3). In Cannabis flushed for 14 days, nitrogen was 6.7% lower than the zero-day flush treatment (Figure 3a). Continuing to feed nitrogen can increase its concentration in the plant, reducing the need for the plant to use its reserves for essential functions. Phosphorus, potassium, calcium, magnesium, and sulfur were similar for all four flushing treatments (Figure 3a-b).
There were changes in iron concentrations due to flushing treatments. Iron was at least 50 ppm higher in flower flushed for 14 or ten days (Figure 3c). Small changes were observed for zinc as well. Zinc was approximately 73 ppm higher in flower flushed for 14 days. The fluctuation in zinc did not follow a consistent pattern like iron. There was no significant change in manganese, boron, copper or molybdenum (Figure 3c). Nutrients like iron and zinc can accumulate in growing media over time. Feeding water during a flush may release some of these nutrients from the media into the plant. Additionally, zinc and iron are involved in the breakdown of chlorophyll occurring during senescence.
Data generated from plant parts, whether it be nutrient or THC concentrations, is naturally variable as only small samples of plants are consumed in the analysis. This may explain some of the variation seen in the data presented here. In other crops, ranges exist which indicate whether nutrient concentrations in leaves are deficient or sufficient for growth. All nutrient concentrations detected in this study are within generally accepted ranges of leaf concentrations for each nutrient. Toward the end of the Cannabis flowering cycle, the plant starts to naturally senescence. Plants that are nearing the end of their life cycle will uptake fewer nutrients as they remobilize nutrients from other plant parts. This may explain why little difference was observed in the mineral content of flower flushed for different times.
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ber
Aug 20, 2021
continued:

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linegraph_c.png

Figure 3. Mineral content of Cannabis flower of plants flushed for 14 , 10 , 7 , or 0 days. (a) Nitrogen, phosphorus, and potassium content of Cannabis flower. (b) Calcium, magnesium, and sulfur content of Cannabis flower. (c) Micronutrient content of Cannabis flower.

Extraction Efficiency
Trim from Cherry Diesel was sent to an extractor to determine extraction yield and preferred characteristics of the wax. Cannabis flushed for 14 (17.97%) or ten days (18.21%) had the highest extraction yield compared to the seven (16.39%) or zero (16.17%) day flushes. However, the appearance of the wax for the zero-day flush was preferred over the other flush periods (Figure 4a-d). The zero-day flush was the clearest with least amount of nucleation. Although increased flush time resulted in higher extraction yields, the finished product was not as desirable for extraction.

Figure4.png

Figure 4. Wax extracted from Cherry Diesel trim flushed for (a) 14 days, (b) 10 days, (c) 7 days, or (d) 0 days.

Taste and Smoke Characteristics of Flower
Cured flower from Cherry Diesel was evaluated by a group of industry experts for flavor and smoking characteristics in a blind taste test. Overall, the duration of the flushing period had no impact on flavor, smoothness of smoke, or color of ash (Figure 5a-d) (P < 0.05). The seven-day flush period had the highest “bad” rating (21.1%) and the 0-day flush had the highest “great” rating (16.7%). Most panelists rated the flavor of the samples as “okay” or “good”. The ten-day flush had the highest “okay” ratings at 48.6% and the 0-day flush had the highest “good” rating at 47.2% (Figure 4a).
The terpene profile, as tested by a third-party laboratory, indicated earthy to spicy flavors for all flush treatments. Most panelists rated the samples as either “earthy” or “sweet” (Figure 5b). Sweet was chosen as the predominant flavor by 38.9% of panelists for the ten and seven-day treatments and 32% of panelists selected sweet as the dominant flavor for the zero-day treatment. Panelists selected earthy most frequently (32.4%) as the dominant flavor for the 14-day flush.

Taste test panelists rated the ash color and smoke quality of each sample. Ash color was predominantly black or gray (Figure 5c). Smoothness of the smoke increased with decreasing flushing time, although was not significantly different (Figure 4d). Thirty-six percent of testers rated the smoke from the zero-day flush flower as smooth whereas only 19.4% rated the 14-day flush flower as smooth. The 14-day flush had the highest percentage of harsh ratings (41.7%) compared to other samples. Panelists were asked for their flavor preferences before testing in order to determine whether personal preference would affect taste test results. Statistical analysis determined that personal preferences did not influence taste test outcomes (data not shown).
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Figure 5. Results of blind taste test of Cherry Diesel flower. (a)Ratings for overall taste of flower as bad, okay, good, and great. (b) Ratings for flavor profile of flower as earthy, sour, spicy, or sweet. (c) Color of ash after smoking of sample rated as white, gray, or black. (d) Smoothness of the smoke while smoking rated as smooth, medium or harsh. Significant differences are indicated at the 0.05 probability level.

CONCLUSION
In a first of its kind study, Rx Green Technologies evaluated the effects of flushing period on yield, potency, terpenes, mineral content, and taste characteristics of Cannabis flower. Overall, the length of the flushing period did not impact yield, potency, terpenes, or taste characteristics of Cannabis flower. Taste test results indicated a trend toward improved flavor and smoke quality with the zero-day flush. While there were no significant differences in nutrient content, there was a trend toward increased iron and zinc in flower flushed for 14 days. The results of this trial indicate that there is no benefit to flushing Cannabis flower for improved taste or consumer experience.
 

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