Is this a pH problem or a deficiency?

[Tokabowl]

This bubblegum is 17 days into veg from clone (see my grow @ http://www.icmag.com/ic/showthread.php?t=24905), and there are yellowish/brown/rusty patches starting to appear on some of the larger leaves...








(soz the pix are real bad quality but they look similar to dnb's plants you can see @ http://www.icmag.com/ic/showthread.php?t=24942)

I'm watering them about 2 times a week (when the soil is dry the first inch or so), and i give them nutes everytime...(the guy at the hydro shop told me to feed them every watering...). It is in a 15 litre pot and water it about 2 to 2.5 litres everytime (till there is a little runoff, not too much as i believe this just flushes nutes from the soil away (?) ).

The first time i watered them i gave them:
Canna Terra Vega:1.5ml/l
Canna Rhyzotonic: 4ml/l
I didn't have any pH down at the time so the pH ended up being 7.8 ....
Then 5 days later i gave them:
Terra Vega: 3ml/l
Rhyzotonic: 3ml/l
Cannazym: 1.5ml/l
pH=6.0
I then moved to full strength for the next time:
Terra Vega: 4ml/l
Rhyzotinc: 2 ml/l
Cannazym: 2.5ml/l
pH=5.9
And have watered them once with this full strength solution since.
They are now at 18 days veg from clone.
I forgot to add: my RH is quite low too, around 30% when lights on, 50 when off... I've put wet towells in the box to hopefully solve this...

Anywayz, what do u experts out there think is the problem?
Thanks a lot

Safe

 

[Blackmelo]

hi Toka,
can't really tell what the prob is on yours or dnb's plants but your ph is way too low and is the most likely culprit imo.
For soil, you want a ph of 6.4-6.9

 

[Tokabowl]

Hi Blackmelo, thx for helpin out.
I'll keep the pH up in that range next time they need to drink. Is giving them nutes every watering ok? I've seen on here that once every 2 or 3 waterings is quite common... they dont seem to have nute burn tho

 

[10k]

Of course the hydro store guy wants you to use up those nutes sooner rather than later.... so he can sell you more !

In reality, feeding every time you water is way too much. Every third or fourth watering is pleanty in most soil grows.

btw... if you're judging when to water based on the first inch or so being dry like you mentioned, then its very likely you're watering way too often. The soil at that "first inch or so" is NOT a safe representation of how wet that soil may be down in the middle to bottom of that 15 liter planter. You're much better off judging when to water based on when the planters become very noticably lighter weight.

Plus that 2 to 2.5 liters isnt enough for a fifteen liter planter. Give them a good drink, then wait a few minutes for it to sink in and down and then hit em again, until you see some additional runoff. This will insure that ALL the soil has a chance to absorb the watering and that none of the root system will sit in a dry pocket. Pick up the pot after such a watering, see how heavy it became, then dont water again until its noticably light again. You'll get accustomed to judging when to water using this method very easily, and you'll be glad you learned it.

If you're confused by the way I explained that, please do a net search for the keyword string "lift the pot" for further explaination.

ps...
Full strength solution right now, is probably way too strong.
Let the plants tell you when they want more and not when they're suffering from too much. I'd rather have a modest size filet mignon & lobster dinner, then try to eat the whole damn cow and end up getting sick.

pps...I cant tell from the pictures, but agree with blackmelo that the pH is jumping around a little too much.

 

[Blackmelo]

Hi Toka,
there is not a clear answer to your question. It is theoretically better to feed exactly the right amount on every watering instead of feeding twice the amount on one watering and then plain water on the next.
However, chemical nutrients tend to build up in the soil over time and flushing it out once or twice would be a good idea...
So if you are fedding chemical, it might be a good idea to rinse out the soil once in a while.

If you are feeding organic, then feed every watering. Simple as.

To find out exactly how much you should be feeding in vegg and in flowering, go to this site:

http://www.angelfire.com/cantina/fourtwenty/articles/profiles.htm

According to their charts, it tells you in vegg you want a ratio of about N,P,K: 200-300 ppm, 60-80 ppm and 150 -250 and in flowering you want something like 40-100, 100, 100.

Type in the details on the back of your nutrient bottle into their nutrient calculator and you can then work out how many ml you need to be feeding to reach the required ppm level.

I've tried this on two fertilizers already and it gives you the exact feeding amount instead of the exagerated feeding amount most manufacturers print on their bottles.

Ps: don't want to step on any1's toes but 2-2.5 liters is plenty and is what I feed...

 

[mace_ecam]

According to their charts, it tells you in vegg you want a ratio of about N,P,K: 200-300 ppm, 60-80 ppm and 150 -250 and in flowering you want something like 40-100, 100, 100.

You could also use an NPKMg of 100-100-200-60 mg/Liter for the whole grow, from veg to flower

 

[Tokabowl]

Hey blackmelo, 10k & mace, thanks for the answers.
I'm gonna feed them just water with the pH adjusted to 6.5 next time around (prolly 2moz) to make sure salts dont build up, and give them nutes once every 3 waterings from now on and see how they respond. Also, im gong to water them more and test the runoff for pH, see where its at. I'll post results asa its done.
Thanks again

Safe

 

[Tokabowl]

Just watered the girls with the solution at pH 6.5, and the runoffs for all 3 plants have a pH very close to 6.7, does this sound right?

Thanks

 

[Desiderata]

Yep, that's right Toka.......6.7 PH is perfect (6.5-7.0) for soil. I think salts were building up on you from too much nutrients, from what you shared.

 

[Guest]

hi Toka,
can't really tell what the prob is on yours or dnb's plants but your ph is way too low and is the most likely culprit imo.
For soil, you want a ph of 6.4-6.9

I agree... your pH is too low and it's causing K and Magnesium to be unavailable. Lack of K will cause that kind of intervenal chlorosis, I believe.

I feed my plants in soil at about 6.5 - 6.8, FWIW.

.canine.