High ec in runoff

**toblue** · 10-06-17, 09:50 AM

Tested my runoff today for the first time and it is coming out at 2.00 ec. I am feeding twice per day at 1.4 ec, 5 weeks into flower. Plants look ok but some of the buds look a bit airy.

Should I flush or lower my ec?
The trays that collect the run off have been painted around 6 weeks ago with aqua seal maybe this is adding to the ec, I can't really get a clean tray under.
thanks

**B.A.BARACUS** · 10-06-17, 10:04 AM

You're heading for a possible burn mate.. You could leech the medium, but personally I'd go for s flush.. Put plain tap water through each plant until ec comes out the same as what you're putting in & then put a feed of 1.2ec through & that should get them nicely back in range & then after a few feeds you can up to 1.3 & finally 1.4ec which is plenty...

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**toblue** · 10-06-17, 10:31 AM

Thanks, BA been thinking they may need a flush as they haven't had one yet and they are looking very green. Will do it later today.

By plain tap water do you mean non-PHed. My tap water is soft and around 7.1 PH with little or no register on the ec truncheon.

**toblue** · 10-06-17, 11:41 AM

This is an old tch post I have been looking at not sure if he is talking soil or coco or if it makes any difference.

Woody J
28-09-11, 02:09 PM
Ok, I felt this post may help some of our newer growers with terminology.

Once again, I read a post today with the word "flush" in it.
The guy was just referring to giving a plant a watering.
THIS IS NOT A FLUSH!

So, what is?

Well, there are 3 times when the word "flush" is used, getting rid of nutrient burn or other toxicity, getting rid of unused nutes in soil and getting rid of unused nutes in the plant itself.

LEECHING
When a plant is nearing harvest and water is given to use up unused/stored nutrients, this is LEECHING. To do so correctly, ph balanced water should be used so the plant can use the nutrients.

FLUSHING
When there are unused nutes, weather mid grow or at the end of a grow, that need to be removed from the soil, this is a true FLUSH. To do so correctly, 3x the pot volume in water should be slowly poured through the plant pot. UN-ph'd water should be used for this. That is, water with a ph of above 7.5 or below 5.5, so the plant does not absorb any of the nutrients.

A point of note here,
Quite often, I see advice given to "flush" when a plant displays symptoms of nutrient burn. Usually, flushing is the correct advice to give. HOWEVER, if the soil being used has nutrients in it, it is almost certain that these nutrients will be "time release". Which means they will be released into the soil based on WATERING.
So, if someone flushes a plant that is in pre-nuted soil, for nutrient burn, they are actually feeding the plant, making the problem worse!
The correct way to resolve this issue is to give un-ph'd water (above 7.5 or below 5.5) to prevent the plant absorbing nutrients but is still able to "drink".
Watering with water of a ph 6.3-6.8 after this type of flush will correct any ph imbalance in the soil as a result.

Hope this helps clarify. W

**B.A.BARACUS** · 10-06-17, 12:05 PM

Originally Posted by toblue

Thanks, BA been thinking they may need a flush as they haven't had one yet and they are looking very green. Will do it later today.

By plain tap water do you mean non-PHed. My tap water is soft and around 7.1 PH with little or no register on the ec truncheon.

Just straight from the tap & Then a couple of litres of ph'd feed to finish off.

**toblue** · 10-06-17, 01:56 PM

Well BA thanks mate took your advice and it looks like I have had a very close call. When I took a proper reading the first tap water run off was a very scary 2.6ec from each plant. 50 litres of tap water through each 15 litre pot later and it was as my tap water zero, the last few points of ec in the coco hung on for dear life. Really suprised me how much water it took which has made me rethink my final flush ideas.

They say there is nothing like hands on for to learn how it really is and it don't matter how much you study and read conflicting views it's the real life situations which let you know when you have got it wrong. Think I just got a bit cock sure as everything looked fine. Just took my eye off the ball for a while. From memory I think a similar thing happened to Viz in his second grow and he was kicking himself for not picking up on the lush dark green leaves.

First reading, OMG