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Flushing for harvest

  • by killingyouu
  • May 19 2011 05:11 PM
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Posted 19 May 2011 - 05:11 PM

How do i start flushing my plants for harvest? Do i need to change the frequency of my watering with plane water or just stay on my regular schedule, do i need to use more water, and how long should i flush? sorry for the question bomb.

p.s i'm using soil
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  • Organic,Indoor,Soil,HID

  • Jellyman
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Posted 20 May 2011 - 08:33 PM

There are different opinions on this. Imo the final flush should be the last watering before harvest. There are virtually no nutrients in the substrate after flushing, so if the plants reach the point where they need water again, they'll also need food. Feeding them after flushing would defeat alot of the flushing's purpose. Harvesting the plants when they need water will also be beneficial to the drying process.

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Posted 21 May 2011 - 02:57 AM

I'm still a little confused, So i flush on the last watering? if so how much water do i use? I currently fertilize every 14 days and water every 3-5 days until the pot weeps. Sorry if im not getting this im still a new-b

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Posted 21 May 2011 - 05:28 AM

It's not a problem. Flushing at the end of flowering accomplishes two things. First, it rinses away both nutrients and less desirable (often toxic) buildups from earlier fertilizations. The plant was absorbing all of this stuff before flushing. By rinsing it away, there will be less in the buds when you harvest, creating a smoother (& probably healthier) smoke.

The second reason to flush is because of flower production. Once flowers form, they need time to ripen before they'll make a good smoke. On many pot plants, new flowers will continue to form straight up until harvest. Any flowers that first form in the last week or two of flowering won't have time to ripen, and those particular bits of flower will yield a speedier, underdeveloped high. Flushing away all of the nutrients minimizes new growth so that more of the harvested bud is ripe.

Since flushing is a kind of overwatering, your plants will go longer than normal before needing water again afterward. So in your case, you might aim to flush a week before harvest.

Some people say use three times the container size in water to flush with. Some say flush until it runs out the bottom clear. Since the soil will be fully saturated after flushing, no matter how much you flush with, you can't really flush too much. Just run water through the pot until you think the soil is as clean as it'll get.
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Posted 21 May 2011 - 07:13 PM

Thank you for the well written responses and the much need info.

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Posted 21 May 2011 - 10:43 PM

Yeah, Jellyman is spot on as usual. Flushing does just that -- it rinses or cleanses the soil of both toxic build-ups but also of ferts built up in the soil. Thus after flushing your plants can't uptake any nutrients from the soil, which causes them to draw down their internal storehouse of nutes. This is the main reason to flush, so that the plant draws down its nutes and thus you don't have nutes in your bud. Improves taste.

That's also why, as Jellyman said, it defeats the purpose of flushing to feed after the final flush.

A lot of people are confused about the final flush. I see posts on here from guys saying they've been flushing for a week or two -- apparently they think that the flush and the whole week or more afterwards is "the flush." No, the flush is the actual running of all that water through the soil. I usually haul my plants up to the shower and use the handheld hose to just run water through them for 30 minutes or so. And yes, afterwards the soil will be very wet so you won't need to water again for a little while, until the soil dries out as usual.

FYI, flushing is advised not only as a final step before harvest. Some growers also flush when they flip to 12/12, to get rid of the built-up veg ferts in the soil and get ready for flower ferts. Also a good idea to flush any time you have nute burn and/or a pH imbalance.


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