The half that are telling you to flush are taking the piss. Which really doesn't help.
The concept of flushing was brought about by people that had no actual idea what they are talking about. They seem to have the idea that the nutrients will some how make their weed taste bad and fill their bodies up with chemicals. Which is bollocks, it just doesn't work like that.
The only branch of horticulture that subscribes to stupid theories like this is cannabis production. You won't find a farmer that comes along and starts flooding his fields in a vain attempt to wash away all the nutrients from the soil.
OK. Some of the flushers are just stirring shit up.
Flushing is a Myth.
Flushing is typically used on Pots/Soil. Flushing removes excess nutrients from the soil just as the plant stopping to feed from the soil. When the plant stops feeding, it starts to cannibalize it's own leaves for nutrients. How you can remove nutrients from plants planted in the ground is beyond me. However, you can flush away Nitrogen because it doesn't fixate. Still, by that time, the plant isn't taking it up anyway (not much anyway).
Here's a paper from University of Guelph on Flushing Cannabis.
https://atrium.lib.uoguelph.ca/.../Stemeroff_Jonathan...
"Flushing was found to be ineffective in removing any significant amount of nutrient from the bud."
Read the first two pages to skip the technical details.
Here's a paper from 1977 courtesy of the NRC (National Research Council)
and the tobacco industry.
https://cdnsciencepub.com/doi/abs/10.4141/cjps77-023...
As famous as the tobacco companies are for their accurate and comprehensive studies, the only thing this study from 1977 says is that Magnesium and K increased yields and market value. K much more so than Mag, and that K may help remove certain "health hazards" from the smoke while adding others. It ends with:
"Consequently, K fertilizer would appear to have both positive and negative effects on smoke quality, and bioassays of the experimental samples will be necessary to evaluate the potential benefits or hazards to health associated with varying K levels in tobacco leaf"
thanks speedwell. So you think I should keep my nutes going all the way to harvest? Everyone keeps saying my planst are sick and 'starving' becasue of the leaf color, but no one seems to suggest changing my feeding approach...
Keep feeding until you're ready to harvest. The only down side to that is wasting a little fertilizer. As you move closer to harvest you'll notice leaves start to yellow. Not only at the bottom, or the top, but dispersed. That's when you know your plant is starting to harvest feed from itself, and less from the soil.
Good luck.
