When do I stop fertilizing before harvest

Large roots before the beginning of flowering need to feed the roots of the plant to the maximum and during flowering also including phosphorus potassium magnesium nitrogen but in smaller quantities any complex fertilizer for flowering will be ideal and at the end of flowering when there are 2 weeks left before harvest you need to completely stop feeding the plant and do a rinse with water or water with a special liquid to remove excess salts and minerals

Less nitrogen for sure, but you still need it for a healthy plant. During the flower stage all successful growers increase the P/K. What else do you need, all the trace minerals you’d find in a naturally enriched soil. As far as flushing. The plant will naturally fade as it matures (the leaves will turn colors). The need for flushing is to correct a toxicity of some sort.

That really depends on the type of fertilizer you’re using. If you’re applying mineral or organic nutrients in liquid form, I recommend stopping about 10 to 14 days before harvest. During this time, you should only water with pH-adjusted water – that should be just fine. You can also water a bit more generously during this phase to flush out any remaining nutrients. Personally, I use organic fertilizers and believe that stopping nutrient input 10 to 14 days before harvest is completely sufficient. At this stage, the plants are in their final ripening phase – it’s no longer about flower production, but rather about maturation.

is a toxicity building up? Restricting building blocks will never result in bigger buds, assuming you are not overdosing it. yes, your leaves have stored nutrients and will sustain a plant if you do. it's fine to be lazy, but don'tlie to yourself about it somehow magiclaly improving quality or yield. it's not about "more." it's about maintaining levels around the roots that meet needs of the plant. you cannot force feed it. it is not foie gras. this s about concentration around roots that are sufficeint and don't lockout other nutrients.. .and vice verse for all other nute molecules. studies show going over 190ug/L doesn't result in anything measurably different. There may be genetic variety or environmental factors that shift exactly what this is in your garden, but it clearly shows that just loading up on "more" of it is only going to flush a shit tone of excess, unused P/K down the drain. A significant portion of P/K intake is done through active transport and not simple diffusion across a membrane on root. The plant sends out carrier molecules to bond with specific p/k molecules and re-enter. there are feedback loops to control these processes. The plant actively grabs p and k on demand rather than mass flow intake (some does enter through basic diffusion, too). the right amount is the goal. Trial and error will get you there. Any toxicity arises tells you that you provided too much leading up to that point -- whether it takes days, weeks or months to occur, it is still true. If deficiencies arise, that tells you that you did not provide enough leading up to that point. So, you find an upper threshold and dial back. this probably resutls in some waste, but ensures you are not shorting the plant in any way. any change in overall formula can impact the uptake of other molecules, so if the formula changes, you may need to tweak other things. Increasing Ca may impede availability of some other nutes.. then those nutes also have to be increase to mitigate it, which can aldo domino into impacting uptake of even more elements, lol... it is simple but complicated. drastically shifting the formula is more akin to masturbation. a 20-30% drop of N as you go into flower is probably the only thing you should be shifting significantly. Any excess p/k you feed in vege that doesn't cauase a toxicity will be stored for use later -- not saying thise hypothesis is correct, but the fact you don't get deficiencies or run into toxicities is the proof of how it was supplied/used in proper amounts. if youload it up with a particular nute and end up with a fried canopy, have some humility and accept that your behaviour caused it.