70's natureboy
Well-Known Member
Properly grown weed may not need to be flushed. Over fertilized weed can taste harsh and consumers don't like it. If you over fertilize then you should flush if you want repeat customers.
Scientific Trials Show No Chemical Difference in Plants After Flushing
V256.420
Well-Known Member
Got myself two Active Aqua 2 x 4 trays for my tent and it's ez pz to flush whenever I want now. Got them on a very slight incline and can water all the plants at once and shop vac it all out in seconds.
Lately my Promix has been super acidic so I'm over watering every 2 weeks while in flower with a higher (7.5) ph to combat this. Has worked very well so far
Lately my Promix has been super acidic so I'm over watering every 2 weeks while in flower with a higher (7.5) ph to combat this. Has worked very well so far
Minesflushed907
Member
BullchitSUMMARY
INTRODUCTION
- 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.
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
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.
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.
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.
Cannabis Flushing Study on Grow Nutrients I Rx Green
Rx Green’s research study on cannabis flushing explores the truth behind this urban myth in growing nutrients.www.rxgreentechnologies.com
Minesflushed907
Member
There isn’t a npk test available . And you can smoke that blk ash sparkler having to re-light every 2 minutes Roll that chit up
Attachments
bk78
Well-Known Member
‘Wait a second. White ash coming from flushing?
Doug Dawson
Well-Known Member
Why is it most people who flush complain if they don't their weed smells bad, tastes bad, keeps going out and has black ash? Is it only those who grow really bad weed that promote flushing? I personally have never had joint that was like a sparkler.
getogrow
Well-Known Member
This black ash shit is dumb as fuck. i have fucked up in everyway possible and never seen no damn black ash that has to be relit. I aint NEVER seen no damn joint sparkle either....
Moldy
Well-Known Member
Haha, love to see this argument go on and on. If you think it helps to flush then do it. The data seems to contradict flushing for cannabis but we all grow decent bud so to each his own. I just don't use that high of concentration of nutes throughout my grows so never had sparkles or black ash in my weed except for some shit I bought back in the 60's.
getogrow
Well-Known Member
i seen some rough grows in the 90's , i can only imagine the 60's . and i thought i was old. 
getogrow
Well-Known Member
nah, been there an done that the most. never had mites sparkle in a joint. Of course i have never had that many mites die in buds. that dont really happen either. When their food source dies , they leave to other plants or walls ect....
Star Dog
Well-Known Member
Why do people that don't flush always try to convince others not to?
It says clearly in the info being disgust there's no difference, why waste it in the last 2 weeks then?
I can't understand what Rx Green Technologies has to gain rofl.
Bottom line is you or your punters are happy lol
It says clearly in the info being disgust there's no difference, why waste it in the last 2 weeks then?
I can't understand what Rx Green Technologies has to gain rofl.
Bottom line is you or your punters are happy lol
getogrow
Well-Known Member
Im not 100% they have anything to gain. this may just be a good study. it needs peer reviewed. I have always said if you start your "flush" too early then you will lose weight and quality. This study does not proof it or disprove it but it shows the defs.... so its something to throw in the back of the knowledge truck an carry on.....
Star Dog
Well-Known Member
Yes that stands to reason to me, I only start flushing when I consider it ready, or when your non flushers would chop it.
idk if it makes any odds or not but after the months of vegging and flowering I'm not prepared to take the risk of not flushing.
Blazin Budz
Well-Known Member
Im a man of science so unless you can give scientific proof to disprove this study then im going to stop flushing. You and your bro thinking that the bud taste and smells better when flushed is not science.
bk78
Well-Known Member
But you harvested your last crop weeks early and it smells like hay now.
enough with the bro science my dude until you complete a RIPE crop.
Craigson
Well-Known Member
So basically feeding the plants the last 2 wks is a waste of money.SUMMARY
INTRODUCTION
- 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.
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
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.
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.
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.
Cannabis Flushing Study on Grow Nutrients I Rx Green
Rx Green’s research study on cannabis flushing explores the truth behind this urban myth in growing nutrients.
University of Guelph did basically the same study in 2017 and reached the same conclusion.
Craigson
Well-Known Member
Feeding the last 2 weeks is a waste of $$. As confirmed by the OP study and this study
Star Dog
Well-Known Member
I wouldn’t call 3 months early but then again I'm not one that knows everything.
overdose420
Well-Known Member
There's no bad information here.. just response to lazy gardening. You and your circle are smoking the shit. Its your own issue.. My weed tastes great and smokes perfect.. You are always a student in this industry.. Be humble. And try not to be an asshole!!