The Grow Awards 2026 🏆

When to flush autoflowers?

Heisenherb
Heisenherbstarted grow question 1mo ago
So many people give the advice to flush before harvest but how do I know when to start flushing, how the flowers should be looking? Im at week 8 now, autoflower. They dont seem mature enough but when to start overdrive and then the flushing? Thanks
Solved
likes
Organoman
Organomananswered grow question 1mo ago
No need to drown your plants with gallons of water, just stop all nutrients and supplements and give just plain water in normal amounts and at normal intervals for the last 10-14 days before estimated harvest day. I find this roughly co-incides with stopping all additives once there are approximately 95% brown pistils/hairs, then harvesting about 2 weeks later when there are 98-99% brown pistils. Don't stress about getting everything "perfect".........follow your instincts and learn from your experiences.........eventually you will reach a stage when you will "just know" when to do things.
2 likes
Complain
Selected By The Grower
Ultraviolet
Ultravioletanswered grow question 1mo ago
First you need to understand which method you grow, synthetically or organic as different growing methods have different variables that will require different approaches to "flushing" per say. Synthetic growing you don't need to worry so much about the microorganisms, just flush that medium till it's empty. Thing to remember thoough is that different forms of nitrogen have different mobilities within the soil itself with nitrates no3- being very mobile and nh4+ being very immobile. To separate ammoniacal nitrogen from soil particles it takes 4 - 5 times more water. This is often overlooked and will prevent a autophagic response. Flushing essentially strips the medium of all salts. Autophagy in plants is strongly induced by a low carbon (C) to nitrogen (N) ratio. Thing about nitrogen is it's required for nearly every single enzyme or amino and it's also used to feed the microorganisms which break down sugars (carbon). A plant that detects a shortage of nitrogen will begin to recycle nitrogen from other parts of the plant and use it to feed the microorganisms that ensure oxidative phosphorylation occurs. If that goes then plant dies or runs off 10% , no nitrogen, no survival. Response Inititated. The nitrate ion NO3-is already in its most oxidized, stable form with a nitrogen oxidation state of +5 . Because it is already fully oxidized, it cannot undergo further oxidation and will never oxidize no matter how long you dry or cure it will never evaporate and you will smoke it. Inhaling nitrates will cause yuck, headaches and nausea. During leaf senescence in plants, this process is critical for remobilizing nitrogen from aging "source" tissues to developing "sink" organs like seeds or new leaves, significantly impacting nitrogen use efficiency and crop yield. Autophagy, a critical nutrient recycling process, is linked to nitrogen reductase (NR) in plants, primarily under low-nitrogen stress. Autophagy regulates NR activity and expression, thereby optimizing nitrogen assimilation and utilization. Nitrate Reductase (NR) is the crucial first enzyme that starts the conversion of nitrate NO3-into other usable nitrogen forms THAT WILL OXIDIZE during the dry/cure. Soon as plant is harvested NR will cease to function and nitrates will become volatile and you will smoke them. "-- flushing is bro science myth.. it's modern day mysticism". Beyond your ability to articulate is more accurate. Flushing itself, historically has been just Flushing everyth8ng out the medium. Yes its 100% true thay Flushing the entirety of the salt ions out of a medium for 2 weeks prior to harvest will drop yield like 10-20% and have a impact of final flavourful and smell. This is not.up for debate. The plant still needs to fill those trichomes, plant still has ripening to do, the entire concept is that with a deeper understanding of the underlying mechanisms you can initiate autohpahy by removing almost all.the nitrogen and still have the plant firing on all cylinders, using the carbon to nitrogen ratio.to induce nutrient recycling without sacradicing the yield taste or flavour. No one is saying it's easy-to-use it certainly took me years to get to a point of even having the knowledge to attenpt., but to deny it existence is absurd. With an effort to simplify the entire process let's jist get everyone to grow synthetically and flush everything, that way everything is simplified and no one needs to knee jerk BRO SCIENCE response. Smart people learn from everyone and everything, ordinary people learn from experience, stupid people have all the answers. Anyone needs proof of concept go check my latest diary with 200 views. :) CH#13.
3 likes
Complain
00110001001001111O
00110001001001111Oanswered grow question 1mo ago
3rd - flushing is a tool to fix rootzone issues. ---- flushing is bro science myth.. it's modern day mysticism when you eat pizza, do you have pepperoni in your veins? Is your belly fat congealed mozeralla cheese? No, that would be absurd. Plants may be simpler organisms, but they still have cell differentiation. Interview with the people that conducted a study and blind taste test on flushing before harvest: www.youtube.com/watch It is a red flag when people give a reason for certain behaviour, then after that reason is proven wrong they make up new, more imaginative reasons as to why it still does something useful. "Oh no, it wasn't that thing we said for years... now, i do it because of 'these' reasons! These shiny new reasons that I never mentioned before, yeah, that's the ticket!" It's a case study of insecurity in action. I flushed a few plants early on and got nice and beautiful fades... useless. Don't overfeed it and you are fine. let it fade if you want - but don't let it fade to the point it can't cannibalize itself to support itself. Can't build terpenese and thc from nothing, if the building blocks do not exist in the plant.
1 like
Complain
MindFlowers68
MindFlowers68answered grow question 1mo ago
Looking good due. that far left picture that top cola is looking sick! Your doing a good job. flushing the medium is more when a grower is pushing the limits on a certain strain theve been growing awhile an know they can push it without killing it. then they try to flush it, but I dont think i does anything as far as making the plant finish any diffrent than it would normally . Flushing will help correct soil problems not plant problems imo
1 like
Complain
LoopyTerps
LoopyTerpsanswered grow question 1mo ago
You can flush to correct overfeeding problem with salts based nutrients. If you use organic amendments, flushing is not needed. Many studies have shown that flushing did not change the quality of the end product. You can also "flush" by stop feeding nutrients during the last week to let the plant deplete what's already there and save up a bit on nutrients, not wasting anything is the important part.
1 like
Complain
JonnyTerpen
JonnyTerpenanswered grow question 1mo ago
Ich würde auch nicht spülen, aber du kannst ihnen Magnesium Chelat geben, das ist zum beispiel bei Athen fade drin, oder Flawless Finish von Advanced Nutrients. es soll die pflanzen anregen den restlichen Zucker zu verstoffwechseln und Salze abzubauen. Aber nur Wasser geht auch. Düngen würde ich nicht mehr. 🤠💚
2 likes
Complain
Hashy
Hashyanswered grow question 1mo ago
I don't flush, but just water as normal for the last 2 weeks without Nutrients. You probably have another 3 week or 4 before yours is finished. Wait another week or so before scrapping Nutrients for just water. If you have been feeding a lot then that last 2 weeks there should be enough nutrition in the medium to last to harvest.
4 likes
Complain