Leaves yellowing to early

[HighAzz]

thanks for stopping by. Here's my issue:

about 3-4 weeks in to flowering, for any of my 6 strains, each of their fan leaves start to yellow. Yellowing of the leaves start from the bottom of the plant and works it way up. The leaves start to yellow, then turn brown, dry out and fall off or i remove them.

I know some yellowing is normal towards the end of flowering, but i've got some 10 week sativas. And I think it's crazy that they yellow 3 weeks in.

Everything is in soil, and is hand watered. All of my flowering plants are in a hydro hut. I don't believe that i have the hydrohut syndrome, as i've had my hut for about 4 years now and have had many successful cycles. Most people i've seen with hydrohut syndrome can't even complete 1 full cycle.

Average temps are from 80-84F. Tons of airflow, but ambient temps are a bit high.

Nutez (used at full strength, 1 watering in between feeding):
botanicare pro bloom(soil)
nutz mad farmer (instead of liquid karma)
PK 13/14
DYNA silicate
Hygrowzyme
magic-cal
flora micro (instead of sweet)

i also reuse my soil, but flush everything with water and clearex @ the end of the flowering cycle.

Initially i thought my problem was over-watering. So i've since decreased the amount of water i'm giving, and am trying to water more frequently (every other or every 3rd\4th day).

Could PH be a problem? What's weird (to me is): the Ph of my tap water is 8.0 . After adding the above nutez, the PH of my feeding water is about 4.5 . Shouldn't those nutez make the PH in my water go up, to something like 9 or 10? Maybe Should i add some PH up to get closer to 6.5?

i'll add some pics later today. thanks for the input.

 

[HeadyPete]

Plain old "you didn't feed enough N just before, during and just after switching to 12/12". The plants will use lots of N when they do their 12/12 stretch. The yellowing leaves you have is the result of the plants taking the N they need from their own fan leaves because there wasn't enough available in the soil.

You can dose them with some Grow but I would only do it once, to help them along, as you want the plant N def during the end of bloom.

You need to measure runoff after watering to see the effect the soil ph is having on water ph. Then you need to figure out the difference and slowly adjust your water (after mixing all nutes and additives) with ph up or down to get your soil ph in desired range - 5.8 - 6.8. Shoot for the middle - 6.3.

Most nutes are acidic and will drop ph of water. Things like calcium, lime etc are alkaline and will raise ph. As your pots get rootbound ph will rise.

If you feed 4.5 water and the runoff is 5 (example), this shows your soil is 5.5. The diff between 4.5 and 5.5 is 5. Your 5.5 soil combines with the 4.5 water to balance out a 5. You need to raise the ph of your water to bring the soil up. Ideally you want to adjust this slowly over time so that eventually you are watering with around 6.2 and getting runoff of 6.3. This shows your soil is 6.4.

 

[HighAzz]

Pete your awesome for responding so quickly.


At first i also thought it was a Nitrogen deficiency as well. So i added some botanicare pro grow during the first 3 weeks of flowering and didn't see much of a difference.

i'm thinking more and more it was a problem with over watering (now fixed) and possible PH issues. Thank you for going in detail on PH balancing.

I bought some PH down (mad farmer) yesterday, only to find out that my water + bloom nutez have a PH of about 4.0 . I'll pickup some PH up today, and also test the run off water's PH during the next watering.

 

[B.C.]

Suggestion

Suggestion

If yer reuseing yer soil chances are the PH is going ta be low from the micro activity on the last run, right off the bat. I would suggest amending it with 20-30% worm castings or compost before useing it again. The humus will help keep that Ph in balance on yer next run. I would also try an bring down those temps alil. Imo, because N is so mobile, I think heat helps dive it out of a plant. The plant yellowing from the bottom up does sound more like a N problem than a PH problem. hhmm maybe pictures would help? BC

 

[HighAzz]

thanks for the reply BC. when my light cycle starts, i'll grab some pics and post em.

As far as my temps, i agree with you. I'm in the process of replaning my air circulation strategy. At the moment, AC is not an option due to the small amount of voltage\amps i have available.

i've heard of worm casting, but never used them before. Where do i obtain them? local hydro store? i've used dolomite lime as a buffer before, but can't find anywhere to buy it.

 

[B.C.]

Yeah the hydro store would prolly have castings, yer local walmart may have them too, I would think they'd have D lime also (?). later, BC

 

[cloudz.fromOG]

Hey im having similar problems, do your leaves look anything like this?
I picked the second one a litter early to get a good pic, they fall of easy and have yellow in the veins first.

 

[HighAzz]

thanks for posting the pics, but i do not believe that my leaves have the same charactiersitcs.

The pics of the leaves above show the whole leaf turning yellow. My leaves don't directly do that. The yellow for me starts @ the tip, and works it's way in. by the time the yellow is half way in, the tip of the leaf is brown and dry. I hope that's an acurate description.

I'll have some pics up tonight.

thanks for all of the input.

 

[HighAzz]

thanks for the reply's. Here's some pics:

Larry Og Kush


chemdawg-mystery


left is chemdawg-mystery, right is dabney blueberry


dabney blueberry


abusive og kush








i tested the ph of my veg plants today after fertilizing, and ph was righ about 6.5 . So all is good on that front. WTF is up with my flower room? is this all from heat? maybe 84 is to high?

 

[HeadyPete]

That looks like a whole lotta nute burn on some of those plants. Some others look like light burn.

How far is the light from the plants? There is a hot spot directly under the HID bulb that can burn plants if it is too close. Even if air cooled......

IMHO I would say you are using too many additives and products and frying those girls. I'd bet if you used half the amounts, your plants would be bigger and better. Because the tap water ph is high it almost definitely means that is hard, with dissolved minerals like cal and magnesium. This factors into the strength of your nutes as well as all the products you add.

I would stop using the silicate and hygro, only use the P/K in later stages of flowering - like last 4 weeks if necessary, because you are already feeding a bloom nute, and go easy on the micro and the mad farmer, and lastly, you shouldn't need to add any magi-cal unless you are seeing a mag or cal def. I would seriously be surprised if you still needed it after all the other stuff that is going in there. The big tip here really is less is more.

Next time, to help with the early yellowing, feed 2x the gro a week before switching to 12/12, half grow, half bloom the week you switch, and the same - 1/2 and 1/2 a week after, then go with the bloom schedule.

good luck and you need to constantly tweak your nute doses to suit the plant, not the directions on the bottle. Some strains can take more, some less. The hotter it gets, the less food plants can use, so dial it back a bit more in the warm season.