Thanks, UB, for this awesome post and the thread that follows. Less really is more... I'm in my first grow, but I've been gardening avidly for 15 years. When I started growing weed, I tossed out everything I knew for "the mystique and voodoo" you mention. Well, just for a couple weeks -- I quickly pulled my head out, shook off the fog and said "it's just a damn plant, man!", and my plants are kickin' ass now. They're starting to freak me out with how much space they're filling.

Just a couple little things to add:

1) People either don't know or forget that plants are water pumps. So, the bigger/smaller the plant the more/less water you need. Therefore, the watering regime you had a week ago no longer works with a fast-growing plant like MJ. I've gone from 8-10 day watering intervals at seedling stage to barely keeping up at 4 weeks old with every-other-day waterings. They just suck it up.

2) Newbies: Get a moisture meter. They're 5 lousy bucks at Lowe's, etc. Once you have it and know how to use it, don't argue with what it says. I find mine really helpful 'cause under a 18 hours of beaming HPS light and fanning, that top inch of soil is going to be dry within hours of watering while you may have a root-killing swamp developing down below (thus confounding the "place a finger an inch into the soil" measure). The meter probe lets you see what's going on throughout the pot top to bottom. I'm sure the meter becomes obsolete with experience, but for newbies, I think it's a great way to get solid on your watering approach.

Thanks again, UB!

Works for me.

I have no experience with feminized seeds. My thoughts are, if you're paying for a service or product and it doesn't deliver, then the seller owes you. Other than the inconvenience of having seeds to mess with, I don't turn down my nose at seeded pot. I think it is every bit as potent as the too often hyped "sensi". I have planted many a seed, not feminized, and had few hermie problems. Hermies seem to arise with Mex and other equatorial sativa strains. You just learn to live with it.

Whether or not you toss hermie seeds is up to you. Me, I wouldn't keep them unless they have attributes (phenotype) too fine to lose like excellent potency, vigor, plant structure, etc.

And thanks for the thanks.

Yeppers, another satisfied customer who knows what he wants and is doing what needs to be done.

Absolutely, same goes with plant food or light. You measure a plant's needs based on factors such as size, vigor, color, etc. A plant in the seedling and late flowering stage "needs less" when growth is the slowest.

No shit. I've had to water plants in 3 gallon pots twice a day with at least 1/2 gallon each watering. It all depends on the amount of the foliage, overall bulk and of course temp, RH, etc. Plant culture is dynamic, it is ever changing from the beginning to the end. A master gardener learns to adjust to plant needs/requirements accordingly.

Uhhhhhhhh, you know where that "pro" who recommended that drill can stick his finger. Best bet is water when the pot feels light to the lift. After a few gardens, you don't even need to do that, you just know when the plants need water based on their looks.

You're welcome! And to quote our good friend potroast, "thanks for playing along."

UB

__________________
PLANT MOISTURE STRESS aka leaf edge/tip curling - symptoms and solutions
Note- Due to some technicality, I can not reply to "New visitor messages"

glad you are with us U da MAN

__________________
IT REALY SUCKS THAT SOME PEOPLE WIG AND HOLD IT AGAINST ME FOR TRYING TO GROW A STASH THEY JUST DON'T UNDERSTAND

Thanks man! Really happy to be here! The abundance of master gardeners and the good will of the general membership is refreshing.

Still learning after all these years,
Uncle Ben

Attached Images

JH8c.jpg (75.6 KB, 233 views)

__________________
PLANT MOISTURE STRESS aka leaf edge/tip curling - symptoms and solutions
Note- Due to some technicality, I can not reply to "New visitor messages"

PLANT MOISTURE STRESS - symptoms and solutions (content revised Jan. 12, 2009)

Quite often I hear groans from folks having leaf problems -> “Help, my leaves are cupping and the leaf edges are turning brown!”, or, “My plant's leaf tips are curling down and turning black ....what's wrong?” Unless insect damage has occurred or the plant is suffering from a severe case of calcium deficiency, the plant is trying to tell you that it is water stressed. It's hard to tell *exactly* what the culprit is, and unfortunately the “solution” the grower chooses many times is not the right one. A mis-diagnosis only serves to make matters worse by promoting further decline. I’ll try to cover some of the more common causes that can induce these common symptoms and try to offer a few simple solutions. The ultimate and correct solution is in the hands of the grower.

1. Over-fertilizing - the most common cause of leaf cupping aka leaf margin rolling, leaf margin burn, leaf spotting and leaf tip curl/burn is the overzealous use of too much plant food in relationship to factors such as plant size, vigor and rate of growth. The first unit of a plant to show moisture stress is the leaf at its margins and/or tips, reflected by margin rolling (cupping) or burning. Sometimes copper colored necrotic spots show in the leaf also. A hard, crispy feel to the leaf frequently occurs as well, as opposed to a soft and cool feel of a happy leaf. When you have a high concentration of salts in solution (or in the root medium) compared to lower salinity levels found in the plant’s tissue, water is actually drawn out of the plant across the root gradient in order to fix the ppm imbalance. IOW, this is a natural, osmotic response that serves to equalize salinity levels on both sides of the root’s epidermal gradient. Back off on the amount and/or frequency of plant food. Too much plant food can also burn the roots, especially the sensitive root tips and hairs, which then creates another set of problems such as nutrient deficiencies. A note for the bio folks - as soil dries, the concentration of the remaining salts rises further exacerbating the problem. Leach (flush) your pots once in a while to get rid of excess salts.

2. High Heat - the plant is losing water via it’s leaves faster than what can be replaced by the root system. The leaf responds by leaf margin cupping or rolling (up or down) in order to conserve moisture. A good example is reflected by the appearance of broad-bladed turf grass on a hot summer day, high noon, with low soil moisture levels - the leaf blade will roll in and the grass will take on a dull, greyish-green appearance. Upon sunrise when moisture levels have returned to normal, the leaf blade will be flat. Lower the heat and concentrate on developing a large, robust root system by practicing sound plant culture. An efficient and effective root system will go a long way to prevent heat induced leaf dessication and leaf margin curling by supplying sufficient moisture for good plant health. One short episode of high heat is enough to permanently destroy leaf tissue and cause a general decline in the leaves affected, which often occurs to leaves found at the top of the plant located near HID lamps. The damaged leaf (usually) does not recover, no matter what you do. Bummer in the summer. One can only look to new growth for indications that the problem has been corrected.

3. High Light - yes, it’s true, you can give our faves too much light. Cannabis does not receive full sun from sunrise to sunset in its natural state. It is shaded or given reduced light levels because of adjacent plant material, cloudy conditions, rain, debris and dust collection on the leaf surface, twilight periods of early morning and late afternoon, and light intensity changes caused by a change in the seasons. Too much light mainly serves to bleach out and destroy chlorophyll as opposed to causing leaf cupping, but it often goes hand-in-hand with high heat for indoor growers. Again, back off on the light and concentrate on developing/maintaining an efficient and robust root system. Keep in mind that all but equatorial material receive less light during flowering than during the vegetative stage.

4. Overwatering - this practice only serves to weaken the root system by depriving the roots of proper gas exchange. IOW, the roots are not getting enough oxygen which creates an anerobic condition causing root decline and root rot with the end result showing up as leaf stress, stunted growth, and in severe cases, death. <gasp!> Alot of times folks think the plant is not getting enough plant food (which it can't under such adverse conditions), they add more nutes for a "curative", and just add insult to injury.

5. Underwatering - not only is the plant now stressed due to a low supply of adequate moisture, but carbohydrate production has been greatly compromised (screwed up). Step up the watering frequency, and if need be, organic growers may need to soak the pot from the bottom up until moisture levels reach an even consistency throughout the medium especially with mixes that are heavy in peat. If severe, a little surfactant (liquid Ivory dish soap) added to the drench will help return the organics back to a normal moisture retentive state. If the pot feels light to the lift - it’s time to water. Don’t wait until the soil pulls away from the sides of the pot or leaves droop before you water.

Happy gardening,
Uncle Ben

__________________
PLANT MOISTURE STRESS aka leaf edge/tip curling - symptoms and solutions
Note- Due to some technicality, I can not reply to "New visitor messages"

Like all others have said, thank you! Looking forward to what is up your sleeve! I never though about roots "spinning out" being a problem, but makes some sense when compared to a root ball which has not "spun out".

__________________
Hayduke's "Seldom Seen Garden!"
http://www.rollitup.org/grow-journals/100867-haydukes-seldom-seen-garden.html
The United States Constitution (c) 1791. All Rights Reserved.

Well, the fate of the western world does not rest on me draft, just some thoughts I'm putting together. I've started it and as thoughts evolve I'll finally finish it and post the ditty. Thanks for the kind words.

Yep. The whole drill is for roots to explore as much as soil as possible for maximum uptake of water and minerals. Root spinout is not good. There are ways to address the problem both chemically (copper hydroxide root tip pruning paints) or by mechanical means - scoring when upcanning, using air pruning type pots etc.

Here is one way to address root spinout using Griffin's Spin-out paint...a grow journal.
Spin-Out for chemical root pruning

cya~

__________________
PLANT MOISTURE STRESS aka leaf edge/tip curling - symptoms and solutions
Note- Due to some technicality, I can not reply to "New visitor messages"

I checked out your article on the Griffin's previously, interesting to say the least. I am a little sketched do to ignorance, and the similarity of this product to anti-bottom fouling marine paint. the guys who scrub boat bottoms are exposed to some nasty sh!t as well as the area under the boat slip. I am sure since you are using this product though, there is no health concern. I am interested in the mechanical means as my friend who worked in horticulture for years asked me about cutting the roots...I just figured it was not good, and when I "upcan" my roots look like they have been chasing something around the pot...I thought well there is lots of roots and that is good. Using the net pots is also interesting. My buddy mentioned his local garden center selling cuttings in rapid rooters that they just let the outside roots dry out or cut them off...this seemed like a bad thing to me but now has me interested...Thanks for sharing your experience here on RIU. This is the kind of stuff that keeps this exciting.

¡Mucho Garcia Tio!

__________________
Hayduke's "Seldom Seen Garden!"
http://www.rollitup.org/grow-journals/100867-haydukes-seldom-seen-garden.html
The United States Constitution (c) 1791. All Rights Reserved.

Still standing after all these years. If there was a toxicity issue, my plants would have taken the hit first. Because of the application and plant's root tip response, copper ions are not translocated thru the plant.

Cut 'em. I'll repeat what I've recommended for years - when you upcan pop the rootball out and using a razor or very sharp knife score the roots vertically. IOW, starting at the top of the rootball, plunge the razor about 1/2" deep and draw down to the bottom making sure you cut thru the roots at the bottom. Rotate the ball so that you do this about 4 times around the perimeter of the rootball.

And before you ask, no, you won't get root rot. Yes, you will get profuse root branching behind the cuts. This a very common practice in the commercial nursery trade.

Those pots work fine unless the RH is real high. I have seen roots continue to grow thru and below the pot under humid greenhouse conditions.

De nada.

Tio Bendejo

__________________
PLANT MOISTURE STRESS aka leaf edge/tip curling - symptoms and solutions
Note- Due to some technicality, I can not reply to "New visitor messages"

Cool thanks for the info on the razor technique this is what my friend was suggesting I believe. Makes sense about the plant taking the first hit and the lack of ion transport. good stuff!

__________________
Hayduke's "Seldom Seen Garden!"
http://www.rollitup.org/grow-journals/100867-haydukes-seldom-seen-garden.html
The United States Constitution (c) 1791. All Rights Reserved.