View Full Version : Nft trays, my ph keeps rising!

31-01-10, 03:17 PM
I.ve been growing for quite a while now but this is my first time in hydro i'm using 2x nft trays. I'm ec stays at 1.3 but my ph keeps rising from 6 to 6.8? Why is this? And my cuttings are about 2weeks old is 1.3 ec too strong? When i got the cuttings they were in peat pots so i banged them into the rock wool cubes and placed them in the trays, how long will they take to root out of the cubes? The strain is blue berry if it makes a difference. Thanks!

31-01-10, 05:24 PM
your cuttings should be left to root out before you put them into the NFT tray.....theres a liklyhood the blocks will now become over saturated
in ideal conditions your blocks should root out in around 7 to 10 days

with NFT (and any other large volume nutrient storage system) its important to regualrily check and adjust the Ph of the nutriant tank, its normal that the Ph will vary....its your job to keep it at the optimum levels with regulator additives

01-02-10, 09:20 AM
What shall i do then? Take them out of the tray and leave them to root with out the tray and hand water them?

01-02-10, 09:25 AM
well thats what i'd do......before the over saturated blocks rot what roots you do have in there

01-02-10, 09:26 AM
mate im not to sure how you have gone about your task but i have grown nft and the object is to get the roots outside of the cube before putting into the system.

leave the white wrapper on the rockwool as this forces the roots to grow out the bottom

id say 1.2 is high and would start at 1.0 then monitor the res to see if ec goes up or down if it goes down increase the nutes if it goes up decrease the nutes

when you water rockwool dip the cube into the soloution from the bottom the rockwool will suck up the water dont feed the cube from the top


01-02-10, 09:37 AM
I'm ec stays at 1.3 but my ph keeps rising from 6 to 6.8? Why is this?

That's a good thing, it would only be bad if it was happening over night, in which case I think you put big rockwool blocks in that weren't balanced. But ideally you want your pH to drift up over the life of your rez (100% addback point for most growers). The only problem is that you're starting your pH a little high. It would be best to start it around 5.4 and let it drift up slowly over the course of a week and when it gets out of what ever range you think you want it at dump the rez and start again. Don't try to lower it after the initial set.

01-02-10, 10:10 AM
the reason your ec is staying at 1.3 is beceause the rockwool is just sucking up the soloution as the roots havent hit the mat yet my opinion is to start off with low ec and to increase when the plants tell you

you wont get an accurate reading just yet untill the roots are established in the system tray

but over feeding is a hassle under feeding can be cured

01-02-10, 09:14 PM
Right cool, thanks alot for everyone who,s answered its helped me alot. I've just had a look at the bottom of 2 of the cubes and there is roots popping out of them both! They've been in cubes since wednesday