Posted on by Jason Gibson

The reasons you need to flush

The reasons you NEED to flush.

Flushing hydroponically grown plants is important, but so many ignore this critical step!

I will explain in a small tutorial as to why you should.

Most gardeners that grow any consumable crop should employ flushing to maximise the potential of their hard-earned fruits!


  • Flavour
  • Aroma
  • Taste
  • Effect


When flowering crops are approaching the end of the cycle the majority of the flower is fully developed, the internal processing has now shifted focus to maturation (ripening)

Basically, when you’re approx. 10-14 days away from harvest there is no point adding food.

Some nutrient brands encourage feeding to the very last day, even at high doses, now to be fair these brands do incorporate cleansing solutions on a weekly basis, but if the flower has reached genetic potential adding food will only remain behind in the plant itself making the final product/s taste bitter or draw quite harshly, burning the throat, uneven burning and some brands if used to the end actually mask the flavour too!

The best way to approach flushing at the end is when you predict the plant is 1-2 weeks away from finishing.

Drop the daily feeds by 25%, 50%, 75% 100%

For example, if on week 8 your EC is 2.4 the second day of week 8 you would lower the feed to EC 1.8, 1.2 and so on.

The depletion of food makes the plant focus on maturation and any nutrient needed that is unavailable at any specific EC would simply be translocated from the older growth of the plant to sustain the maturation process.

By doing this, as week 9/10 approaches your plants will show a beautiful display of colour, see the chemistry of leaves diagram below.

Chemistry of Leaves

We spend months growing our favourite plants, don’t think by adding more nutrient this will result in an enhanced super finish, if anything feeding late can restrict the plants true genetic potential, don’t undo all of that good energy by feeding too late, especially if the emphasis is on quality.

Let the plant breathe and “de-clog” and you will be amazed at the difference!

Reasons you need to flush hydroponic nutrients