al6

I'm currently doing the passive hydro wick system but I have a problem. I had to leave town for a week so I filled my resivore with plenty of water. The PH was at about 6. When I got back the leaves were all turning brown and falling off. They used a lot of water but there was still enough left for a couple more days. The problem is that the PH raised to almost 8. When I'm home I simply water them everyday so I know the Ph is fine. I've got to leave town again and I'm afraid I'm going to lose my crop.

Should I drop the Ph to 5 before I go?
Is this normal for a passive setup?

Takshaka

Your pH should be 5.2-5.8 in hydro...if it started at 6 it was already high. What nutes are you using?...you shouldn't be seeing that much drift with good hydro nutes (unless they're organic).

The best solution may be to get a much bigger reservoir and start pH at 5.2, hopefully this should be enough to stop the pH going much over 6 in a week.

Hope this helps

al6

The initial 6.0 Ph is based on Ed Rosenthal's book "Easy Marijuana Gardening" pg 37 which suggests 6 - 6.3. The directions in my Ph test kit suggests 6 - 6.5. I'm not saying you're incorrect I'm just explaining my reason for choosing that level.

I get my nutes from a local hydro store that makes the stuff themselves. It's a couple of old farts that have been doing this for 30+ years. They claim the recepie is from Holland. Who knows? Their 2 part Veg formula worked great and I had to make no Ph adjustments. I'm only 2 weeks into using the 2 part bloom formula for the first time. I'm going to give your lowering the Ph idea a try and see what happens.

I was wondering if the water just sitting there stagnant had something to do with it. They suggested this formula to me thinking I was going to use it in a drip system which I will eventually. Would water movement help solve my problem?

I've just got to get through this crop to pay for all my ultimate setup. It's the poor boy setup for me till then. I can't even afford to smoke the harvest.

Takshaka

I haven't got that book but I'd guess they're talking about soil...pH levels are different in soil and hydro.

I have no idea whether stagnant water will cause pH fluctuations. Doing something to aerate the water is something you should do anyway, increasing the oxygen content is a good thing whether it helps your pH problem or not.

Nutrients like GH Flora series contain a pH buffer which does an excellent job of keeping the pH at a stable level. The nutes you've got may be good but I doubt whether they have a pH buffer. I realise you're on a tight budget so you're not going to be able to switch nutes for this grow, but if you're going to be away from your plants for this length of time on a regular basis switching will make your life a little easier with your future grows.

Starting the pH at 5.2 will help, but the chances are by the time you get home it'll be up to about 7 which is going to cause problems...this far into your grow and with so much riding on it I'd hate to see you lose your crop or have your yield reduced significantly. I think switching to a reservoir that's about twice the size will help keep the pH a little more stable, it's still likely to rise but shouldn't get so high, you should get away with minor fan leaf burns.

How soon are you going away? If you have time to let the reservoir run down like it will when you're away you'll get a better understanding of how and when the pH rises...I suspect you'll find that the rate of change increases as the water level falls and may only reach problem levels in the last couple of days.

Good Luck

OzGrowa

Gudday there,
The reason the Ph is rising is that the K chelation process in the nutrient is not satisfactory, the use of the P from the solution initially will mean the level of K is in excess, without a chelating agent this causes problems. With every day water replacement and monitoring this is no a problem, but as Takshaka has mentioned, the useage of h20 is large and the EC useage will be much less, leaving a very concentrated and toxic solution remaining in the tank whilst you are away.

This coupled with a lack of movement within the solution spells a recipie for 'the rising Ph'

What you need to do is drop the EC to about half strength, this slows down the metabolic rate of the plant and from this the water useage, the nett effect will be a more stable PH whilst you are away.

regds,
OzGrowa

al6

First of all it is good to hear from the two of you. I've enjoyed reading many of your post and I'm glad we're all on friendly terms

Alrighty then...I rechecked the book and he is talking about hydro not soil.

I put a pump in for movement out of a tile saw I have.

Is PH buffer something I can purchase and add to the water?

I'm leaving tomorrow and I dropped the Ph to 5.2 and filled the res more than before. I'm only leaving for 3 days this time so I think I'll be ok.

I appreciate your advice Oz but you are using a couple of terms I don't understand. EC & chelation process. Are you saying I should go 1/2 streangth on the nutes?

I'm not sure if this helps you help me but my bloom formula is 2 part. Part one is 0-3-6. Part two is 1-0-0. Is a chelating agent something I need to add. Is that the same a ph stabilizer.

I'm a little confused but I am trying to undertand what you are talking about. I guess I need you to expound a little.

Thanks for the help Gentlemen. It is appreciated.

OzGrowa

gudday al6,
Chelation in hydroponic nutirents is usually in the form of iron (Fe) (EDTA), which is added when the nutrient is made, its basically a slow release system that keeps the elements in check, and from this the PH in the correct range. During flowering this is important as the PH wil often rise to over 6.0 due to the high P and K in the bloom mixes. Do a search for chelation if your interested in it more, there are 3 main chelates used, EDTA is only one of them.

EC is simply the strength of the solution, or the electrical conductivity of it, some folks use PPM meters or EC meters, yes I was suggesting you run it at half strength just while you are away.

Making a nutrient is very easy, the only problems with it are i. chelating agents and ii. making a large enough batch to ensure consistency of product. These qustions you may want to ask your local shop guys, although I have used similar mixes made at hydro stores and they have performed real well.


just some ideas, and a lil expansion

OzGrowa

al6

I had an old pump lying around and was able to convert my pasive wick system over to and ebb and flo for about $20. The PH is no longer rising.

Now I just need to figure out when, how long and often to water.