Dispelling The Myths: The Importance Of Flushing Your Plants Before Harvest
The following blog on plant flushing is a guest post from Advanced Nutrients. The views, thoughts, and opinions expressed in the text belong solely to the author, and not necessarily to the CannaCon organization, employees or other related individuals.
Within the world of cultivation, there seems to be debate over the topic of plant flushing. Opponents of the technique believe that flushing plants prior to harvest will rob them of vital nutrients — an obviously bad idea. On the other side of the divide, advocates proclaim that flushing frees the plants of excess nutrients and contaminants and leads to an overall higher-quality product.
In this article, we’ll explore the truth about flushing: Precisely what it is, why it’s so important for growers to flush their plants, and the best way to go about flushing for maximum benefit.
What Is Flushing And Who Should Do It?
Before we get into the reasons why flushing your plants is so important, we need to understand exactly what it is. Flushing involves watering your plants without any added nutrients for a period of time — anywhere from a day or two to a week or more, depending on your growing medium — prior to harvesting. The purpose of this is to allow the plants time to use up the nutrients that have already built up within them, thereby lessening the overall nutrient and contaminant load of the final product.
We recommend flushing for growers of all types, whether hydro, coco coir or soil — though the time period for flushing will vary, depending on the medium.
The Importance Of Flushing
Though some in the industry have argued otherwise, the importance of flushing your plants has been affirmed by the vast majority of serious growers. Most experienced cultivators have tried not flushing before harvest, which has caused them to experience first-hand the glaring difference in quality of the yield.You see, during the growing cycle, your plants store excess amounts of nutrients, salts and other compounds. If you don’t allow the plants a chance to dispose of these surplus compounds by flushing them before harvest, your final product will be much harsher and more bitter tasting. Failing to flush can also cause your product to suffer from other negative side effects, such as black ash and an unpleasant chemical taste and smell.
The truth is, not flushing nutrients before harvest can seriously compromise the quality of your high-value crops.
To Flush Or Not To Flush: Examining The Arguments For And Against
Despite the overwhelming majority of growers who understand the importance of flushing and have verified its benefits through their own practice, there are some who argue against it.
The anti-flushers make a few bold claims, including:
- Robbing plants of nutrients at any stage of the grow cycle is counterproductive and does not benefit growth in any way.
- Once nutrients are absorbed into the plant tissues, they are there permanently. The plant cannot expel them or use them up simply by denying it more nutrients.
- If flushing was in fact a beneficial practice, then plants grown in hydro would always taste better than plants grown in soil because soil cannot be effectively flushed.
- Withholding nutrients causes stress to the plants, which impedes growth rather than encouraging it.
- Flushing plants is “pseudoscience” that has not been supported or backed by any legitimate scientific studies.
Let’s address these anti-flushing arguments one by one.
- Flushing your plants does not involve robbing them off nutrients. On the contrary, it allows your plants the chance to use the excess nutrients they have accumulated throughout the grow cycle. When you feed your crops full nutrient loads right up until the time of harvest, they retain an overabundance of compounds that affect the quality of the final product — including its taste, smell and overall smoothness.It’s also important to note that the main purpose behind flushing is not to encourage substantial new growth — although, flushing can cause your crop’s floral blooms to swell, since plants are not expelling all their energy on nutrient uptake.
- Any grower who has experienced nutrient burn knows the argument that plants cannot expel excess nutrients holds no weight. Ask any seasoned cultivator how to fix nutrient burn and they will tell you: You need to flush your plants and allow them time to use up the excess nutrients.The same logic applies to pre-harvest flushing. You’re giving your plants just enough time to use up surplus nutrients, salts and other compounds.
- The argument that soil can’t be effectively flushed is simply illogical and just plain wrong. Plants grown in soil can be flushed — it just takes a longer period of time than flushing plants grown in hydro or coco.
- It’s true that withholding nutrients places stress on plants and causes them to increase defense compounds. However, in certain plants, the primary defense compounds are actually the most desirable constituents, so flushing before harvest can significantly increase the value of the final product.
- At Advanced Nutrients, we employ the largest team of Ph.D. botanists, microbiologists, entomologists, hormone specialists and organic chemists in the industry. These scientists are dedicated solely to studying cultivation best practices and are constantly conducting laboratory research. The notion that plant flushing is “pseudoscience” is simply absurd.
The Truth About Flushing
Flushing plants before harvest is indeed a beneficial practice. However, there is a right way and a wrong way to go about it. In truth, the anti-flushers make a valid point when they say that it can rob your plants of nutrients — IF you are flushing with just plain water.The fact is, flushing with plain water can cause your plants to lose some floral growth and resin percentages. This is why it’s critical that you use a quality flushing agent that is designed specifically for the type of plants you grow.
When it comes to a flushing agent, you want to be sure to use one that contains a range of chelates. Chelates are organic compounds that can bind with other chemicals and substances. During the flushing process, these chelates will attach themselves to the excess nutrients, salts and other compounds in your plants and force them out.
At the same time, your plants utilize the stored nutrients they need during these last few days and hours prior to harvest. A high-quality flushing agent will provide your plants the support they need through this process, along with assisting them in purging the excess compounds that you don’t want in your final product.
Timing Is Key: When To Flush Your Plants
Along with using the right flushing agent, you need to ensure you’re flushing at the right time in order to reap the maximum benefits of flushing. Use the following as guidelines for flushing prior to harvest:
- If you’re growing in soil, begin flushing between one and two weeks before harvest.
- If you’re growing in coco, flush your plants for up to one week prior to harvest.
- If you’re growing in hydro, your plants only need to be flushed for one to two days.
Of course, you’ll need to monitor your crops closely during the flushing process to ensure they don’t turn too yellow. Adjust your flushing times as necessary to find the ideal time for your plants.
We're exploring the truth about plant flushing: what it is, why it’s so important, and the best way to go about flushing for maximum benefit.
The Top 5 Discoveries in Cannabis Science of 2019
2019 proved to be quite the year for scientific discoveries in weed. Many of the biggest studies confirmed things we already knew, like cannabis works great for migraines, it kills some cancer cells, or that legalizing weed leads to lower opioid abuse rates. While some studies challenged our most persistent academic understandings of ancient cannabis use, others gave us deeper insights into the plant’s evolutionary origins.
What you’ll find here is a short list of discoveries MERRY JANE believes will have far-reaching consequences — not only in terms of cannabis science, but also for the industry and cannabis culture as a whole. Keep in mind that due to federal restrictions on cannabis research, this field is still in its infancy, and any mind-blowing discovery made today may be debunked by 2020.
That’s just how we gotta roll in the new age of legalization and normalization.
No. 5 — Flushing Weed May Do Nothing for Its Flavor or Burnability
OK, so, admittedly, this first discovery was the least scientific compared to the others mentioned in this article. Nonetheless, it challenges some long-held beliefs about cultivation, and whether cannabis connoisseurs really possess the sensitive palates they claim they have.
In December, RX Green Technologies conducted its own in-house study to see if cannabis critics could tell which buds got properly flushed and which ones didn’t. Flushing is a process where growers feed their plants pure water to wash out any excess nutrients that may have built up in the plant’s tissue. The general rule of thumb is to flush plants for a good week or two before cutting them down and hanging them to dry.
RX Green Technologies’ study not only found that most participants were incapable of telling flushed from unflushed buds, but also most of those in the study preferred the flavor of unflushed buds. Additionally, chemical analyses of the flower showed no discernable differences between flushed buds and unflushed ones, nor were there any detectable differences regarding how the buds burned or ashed.
Of course, RX Green Technologies manufactures two popular chemical feeds for cannabis — GROW and BLOOM — so the company’s study may be biased. Furthermore, the study wasn’t peer-reviewed or submitted to any journals, so it hasn’t been subjected to the same scientific scrutiny as the other discoveries listed below.
Nonetheless, RX Green Technologies’ findings should kickstart discussion on what makes high-quality weed, and whether cannabis critics really know what they’re talking about.
No. 4 — Bees Love Male Hemp Flowers, and We Have No Clue Why
This month, a study published in Environmental Entomology found that American bees flock to hemp farms. The little pollinators seemed especially keen on hemp’s male flowers, even though these buds don’t produce nectar, the sugary-sweet liquid that bees feed on for energy.
While the scientists weren’t sure why bees loved hemp, they did discover that bees would pollinate nearby on non-hemp plants at higher frequencies, simply due to the presence of hemp. On top of that, bees would communicate to their hives where to find the hemp farms, indicating that cannabis plays an important role in overall ecological health, not just commercially-driven agriculture.
No. 3 — Biotechnicians Can Now Customize GMO Weed Strains Using Bacteria
Regardless of how you feel about GMO crops, cannabis has officially entered the gene-tweaking fold. A New Mexico-based firm, Trait Biosciences, announced this summer that it had created a truly transformed cannabis plant, which the company designed by splicing artificial genes into weed via genetically-modified agrobacteria.
This new plant, which does not exist in nature, can produce water-soluble CBD, meaning the modified cannabinoid can be extracted by simply cold-pressing the plant material rather than subjecting it to toxic hydrocarbons like butane and propane.
Trait Biosciences claims it can customize cannabis strains for specific cannabinoid ratios, terpenoid ratios, and other characteristics such as drought- or cold-resistance. While many of these claims remain to be seen, scientists have accomplished similar feats in other crops using the same technology, so we’ll likely see Big Ag move in on our favorite flower sometime in the next decade.
No. 2 — The Most Potent Painkillers in Cannabis Are Its Flavonoids
While the masses are riding high on the CBD craze, researchers discovered that neither THC nor CBD are cannabis’s primary painkillers. Instead, they found that two other flavonoid compounds — cannflavins A and B — actually possessed the greatest pain-killing potential, with analgesic properties estimated at 30 times stronger than aspirin. They published their results in this summer’s edition of Phytochemistry. The results will impact our understanding of cannabis as a pain management treatment, seeing as chronic pain is the number-one reason why Americans get medical marijuana cards in the first place.
Here’s the wildest thing about cannflavins A and B: They’re only found in cannabis. No other plant species are known to naturally produce these two flavonoids. So, while scientists remain fixated on THC and CBD, the scientific community may be ignoring flavonoids and polyphenols — two prominent chemical classes in cannabis that are often overlooked in favor of the cannabinoids’ novelties.
No. 1 — Our Genes May Explain Why We Experience Different Highs
To be fair, this isn’t just one discovery. Researchers found a few genes related to various psychoactive responses with cannabis, and when we add them all together, we start getting a very different picture regarding customized highs, one that’s much more nuanced than what the cannabis industry is currently marketing.
Right now, terpenes are all the rage. These aromatic compounds possibly affect what kinds of highs or moods we experience when we get lit. For instance, the terpene limonene (found in lemons and limes) may contribute to our focused, motivated highs, while myrcene (found in mangoes) may contribute to the sluggish couchlock effect. So, naturally, weed products are now marketed for specific heady effects, such as alertness, euphoria, or sleepiness.
However, terpenes alone don’t explain why some of us get wired on limonene while others may experience completely opposite effects with it. Or why others feel no difference between weed strains or products, which suggests there are other factors affecting our moods and highs.
One study from April found that many people are born with mutant CB receptors, the proteins on our cells that interact with THC, CBD, and our bodies’ endocannabinoids like anandamide and 2-AG. So far, scientists know about 15 different versions of the CB1 receptor, the one that’s most responsible for feeling weed’s sweet high. These mutant receptors bind to THC differently than the average or “wild-type” receptors, which could produce differing psychoactive effects when two people smoke the same kind of weed.
Another study from July discovered that weed activated two separate brain regions in rats. Rats that seemed to experience euphoria from weed had forebrains that lit up the most from THC. Meanwhile, rats that seemed to experience paranoia had their hindbrains light up the most from THC, indicating that genetic differences among the rats were the greatest contributors to whether they experienced “up” or “down” highs.
Some studies found that mutant genes were responsible for the 10 percent of unfortunate people who get (mildly) addicted to weed, while other data determined that the CHRM3 gene, which is linked to psychosis, might explain why some people experience hallucinations when stoned.
Of course, none of the above studies invalidate terpenes and customizable highs, but they do show that our experiences on weed cannot be reduced to a simple Terpene A causes Effect B in all or most people.
What will 2020 have in store for the science of cannabis? It’s currently unclear, but considering that the federal government is starting to loosen up on weed research, and millions — if not billions — of dollars are being poured into studying this plant and its constituent chemicals, you can bet this next year will grant us an even greater understanding of this plant that is, as you read this, already revolutionizing commerce, science, medicine, politics, religion, and culture.
The Top 5 Discoveries in Cannabis Science of 2019 2019 proved to be quite the year for scientific discoveries in weed. Many of the biggest studies confirmed things we already knew, like cannabis