All leaves yellow

[ifsixwasnin9]

I have 4 plants (different strains) going into 8th week of flowering and all have pretty decent buds and lots of (clear) trichomes. Since starting the flower phase I've had problems with yellow leaves except for one plant which is still pretty green. A couple plants also had curling tips but the yellowing started throughout the whole leaf at the same time on all plants and sometimes not from the bottom first.
For flowering I've used Maxi-Bloom by General Hydroponics which is 5-15-14 (and I used it last year) and has Calcium and Magnesium around 3.5-5% and other nutrients.
Why would all my leaves become yellow?
I flushed 2 of the plants over two weeks ago and the leaves have been dying but the buds continue to grow. I even added some Cal/Mag 2 weeks ago and I saw no improvement. Two plants are about 4-5 ft tall and the other is 7 ft tall (a Hawaiian strain).
I'm using 250W x 2 HPS lights at 12 hr/day for flowering and always get good ventilation. I was going to get a pH meter before I started this project but I ran into heat problems with my house so I had to spend money on that.

 

[Alistair]

I know you said that the yellowing didn't always start at the bottom, but it sounds like you might have not given them enough nitrogen the first few weeks of flowering. Giving them nitrogen now, in week eight might be counterproductive, though.

 

[Thailord]

It sounds to me like your flowers are using up any available sugars and proteins stored in the leaves. I would suggest molasses at this stage to suppliment the soil with pottash, trace minerals, and micro-nutrients which are often used up by the plants at this stage of growth. Suggested dosage is 5 ml per gl of water PH set to 6.0-6.5. I tend to go slightly lighter doses at 2-3 ml per gl. Often late in flowering we will see the leaves begin to pale and yellow. If the trichs are not where you like them, I would suggest using molasses and then let them go a few days, you should see some improvement.

 

[4u2sm0ke]

Harvest Time???? I have a St. Clement that All yellowed up even the stalk...And like Alistar said..Higher Nitro is given first few weeks going into flower...Hows the Smell?:hubba:

 

[ifsixwasnin9]

I didn't know anything about more nitrogen at the start of flowering. How come the grow information on the web is so bad?
They have a slight smell to them, not too bad.
- I want to wait for the triches to become cloudy? Then harvest? (I don't want the couchlock). How long do I have to wait for triches to go clear -> cloudy? They've been clear for a month maybe.
- Plants don't use any Nitrogen after several weeks of flowering?
- Can I get molasses at the grocery store? I've never seen pure molasses I think.
I've only grown once before. Thanks.

 

[StoneyBud]

I want to wait for the triches to become cloudy? Then harvest? (I don't want the couchlock). How long do I have to wait for triches to go clear -> cloudy? They've been clear for a month maybe.

THC is clear at it's most pure. That would be that strains most psychoactive, (Head High), point of growth. However, you want as much thc as you can get on the plant before harvesting.

Waiting until you have a 50-50 Clear/Cloudy trichome state on the entire plant would help ensure that your plant has produced as much thc as possible, in a state that gives you the least couch-lock as possible.

The more clear trichomes at harvest, the less couch-lock it will have. Whatever that strains phenotype characteristics are, as some strains have more couch-lock than others, even when harvested early.

 

[ifsixwasnin9]

Most info I've seen says the amber trichomes produce the body high and cloudy trichomes the head high.

- What nutrients do plants need in last half of flowering? Doesn't seem like my Maxi-Bloom flower food has kept my plants healthy during the flower phase.
I used good organic potting soil by Espoma: includes spaghnum peat moss, peat humus, perlite, dolomite limestone and Mycotone (promotes root growth, etc.)

This is one of my four plants (Masterkush) - the other plants look similar. Buds look healthy but leaves don't. Also have a Hawaiian strain that has grown out-of-control at 7' tall with very long branches and lots of buds.

 

[OGKushman]

most info you read is not factual based and research tested.


stoney is just about on the money. plants test higher if you pull them just as amber starts to show.


forget all you hyped up products. Use a simple 3
part and extend the nitrogen into flower. ADD YOUR P/K "maxibloom" crap during last half. P/K does NOT add THC; just weight.

*add weight, overall thc content is reduced.

 

[Gixxerman420]

I know you said that the yellowing didn't always start at the bottom, but it sounds like you might have not given them enough nitrogen the first few weeks of flowering. Giving them nitrogen now, in week eight might be counterproductive, though.

This is exactly what's going on! It's natural and actually beneficial for the end product... Buds grown from plans who fans yellow prior to harvest will carry a smoother smoke than one loaded with nutrients(especially nitrogen) would. If the buds are growing still, leave her alone! Depending on strain, you're either right at harvest or 2-4 weeks from... I wouldn't worry about it! I've had yellowing occur at week 6 in a 10 week cycle... Just keep giving her the flowering nutes and she'll do fine for you!

 

[Gixxerman420]

Most info I've seen says the amber trichomes produce the body high and cloudy trichomes the head high.

- What nutrients do plants need in last half of flowering? Doesn't seem like my Maxi-Bloom flower food has kept my plants healthy during the flower phase.
I used good organic potting soil by Espoma: includes spaghnum peat moss, peat humus, perlite, dolomite limestone and Mycotone (promotes root growth, etc.)

This is one of my four plants (Masterkush) - the other plants look similar. Buds look healthy but leaves don't. Also have a Hawaiian strain that has grown out-of-control at 7' tall with very long branches and lots of buds.

Any idea what your soil or water pH is? Might be nute locked!

 

[PencilHead]

It's called "fade" and is a natural phenomenon at the end of flower, like Gixxerman is saying. If you're not at the end of flower it's a bad thing. At 8 weeks you should be seeing fade. Remember: late fade good; early fade bad.

DO NOT add N at the end of flower unless you're producing beans.

 

[StoneyBud]

Back in January of 2007, I posted some information about this. Nothing I've read since has shown that this information has changed in it's accuracy.

http://www.marijuanapassion.com/forum/showpost.php?p=69278&postcount=12

If anyone knows of information that proves any of what is said in this is wrong, I'd sure love to read the updated data.

 

[Thailord]

Back in January of 2007, I posted some information about this. Nothing I've read since has shown that this information has changed in it's accuracy.

http://www.marijuanapassion.com/forum/showpost.php?p=69278&postcount=12

If anyone knows of information that proves any of what is said in this is wrong, I'd sure love to read the updated data.

Quoted for truth. Very good read.

 

[Budders Keeper]

Two plants are about 4-5 ft tall and the other is 7 ft tall (a Hawaiian strain).
I'm using 250W x 2 HPS lights

This can't be helping.

 

[trillions of atoms]

This is all good info man^^^^^

It sounds like they were just hungry as all and you did good without a PH meter!! I would just go ahead and finish them up with water and chop brotha!

You will end up with some nice homegrown im sure!

There are curing guides here i would check out to improve the quality of smoke too.

CONGRATS!!

 

[trillions of atoms]

Ohh and if you have a sativa strain thats a month off, I would hit her with nutes until the last 10 or so days then give her plain H20.