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Leaves curling under-please help
Posted 21 June 2005 - 08:02 AM
I need some advice ASAP please. Got no idea whats wrong with my plants. Leaves are curling under like some kind of claws(photo). New and older leaves(except big fan leaves). The strain is Hollands hope, 9 weeks old, planted outdoors(porch) in 2 gallon pots. I water them app. every 4-5 days, nute 8:6:6 + Mg. Could it be poor drainage issue ???
Thanks in advance...
- Grow oh likes this
Posted 21 June 2005 - 02:17 PM
Leaf curl/cupping & leaf margin rolling-signs of Plant Moisture Stress
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, and leaf tip curl/burn is the overzealous use of too much plant food in relationship to factors such as plant 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. 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 (in the root medium) compared to the 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, which then creates another set of problems. Note - as soil dries, the concentration of the remaining salts rises further exacerbating the problem.
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 (most times up) 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 upward/inward with the grass taking 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. One short episode of high heat is enough to permanently disable or destroy leaf tissue and cause a general decline in the leaves affected, which often occurs to leaves found at the top of the plant. The damaged leaf (usually) does not fully 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, dust, twilight periods in the 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.
4. Overwatering - for those doing soil, 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 inducing root rot and root decline with the end result showing up as leaf stress, stunted growth, and in severe cases, death. <gasp!> Overwatering creates a perfect environment for damp-off disease, at, or below the soil line. 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 water from the bottom up until moisture levels reach a norm throughout the medium. 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. And of course, leach once in a while to get rid of excess salts.
All of the above issues relate to a plant's internal cell turgor or cell water pressure. If water pressure within the plant's stem and leaf cells are positive, the plant will look strong and stocky with flat leaves that are cool to the touch due to good transpiration from the leaf surface. By the same token, if the water pressure is not up to par, whereby water is being extracted from the plant and not replenished like it should be.... the leaves and/or stems will droop.
Do you know what your PH is at?
- kshow77 and bongwater923 like this
Posted 22 June 2005 - 06:48 AM
It gets me more and more confused:confused: Reading the post I would say that I got 3 out of 5 causes(Over-fertilizing,High Heat and Overwatering).
Reading some old posts I also figured out that I might have a pH problem. Ph of the soil is slightly under 8 which is way beyond optimum(I guess I got too much lime in pots - 25%) but ph of the water I use for watering is just about 6. So, if the soil has 8 and water 6, does it mean that overall ph should be about 7?
- Zapa likes this
Posted 16 December 2005 - 05:07 AM
Posted 30 December 2005 - 10:37 PM
Posted 01 January 2006 - 02:30 PM
<~~~Equal oprtunity grower
hey your ph levels should range anywhere from 6--7.5...unless your skilled enough to control the drops and sudden raises, many are not.
and i do not believe in too much light, photosynthesis is the process which creates energy, a plant cannot create to much energy, energy is then broken down into glucose, a sugary substance the plant thrives on, you cannot have an over energized plant in my opinion.
yes poor drainage is definatly a possibility, i have heard of several techniques to combat this problem, 1: remove plant and soil, layer the bottom with packing peanuts, the kind u get out of boxes shipped to your house, make sure its not the kind that break down under water, layer the bottom of your pot with these, not too many, just a good layer, to wher none of your soil will hit the bottom of the pot, this is a professional green house technique, use at your descretion.
Posted 02 January 2006 - 03:37 AM
Posted 05 September 2009 - 08:56 PM
thanks anyone in advance*
Posted 12 January 2010 - 06:45 AM
I spray it daily almost, with a neutral ph water solution w Epsom salt added...my ph is around 6.5. I use mother Earth super tea. I never water unless the soil is dry. It just seems like the leaves dont fill out completely you know? I just transplanted to a bigger pot about 10 days ago. Ill take your advice and cut out the mg for a little while and see what happens. She still growing though! about an inch per day!
Try not Spraying every Day, Spraying with lights on or Off? Does it normally rain every Day in Nature? Try Every 3rd Day and Lights Off. If Money is not an Issue Try Some DM Liquid Light you actually use this with Lights on with Most DutchMaster Foiler Sprays
Posted 22 July 2010 - 03:32 PM
I hope it isn´t fungus... surely it´s happened too fast for that. Some leaves have rust spots, but not much. They are 8 weeks old, and all of the fast growing variety.. big bud, fast bud etc.
Posted 29 July 2010 - 05:26 AM
I think you might do well to put them in partial shade,or maybe over watering ,I don't think you should be watering during the day,it wont cool them down the roots will stew in the heat.Water them at night.Spain ffs ....I'm a bit jealous.
I have 6 plants outside in large pots(spain), with temp regularly over 90... today, 3 plants have black leaf curl. No visible insect damage, no fertilizer, just soil and water. So I think my plants burned up a bit today, and I´ve just watered them to cool them down.
edit:it was the fifth post reply#4 dirty.I went up there a few weeks ago with 30 litres of rainwater a few weeks ago and the next day or 2 they were back to perfect.end edit.
I have just joined this forum,looking for a cure for my curling leaves.
I thought it might possibly be,lack of air to the roots,under watering,watering from a nearby drain that has a red algae growing in it upstream or many other things it could be..Thank you the first replier and maybe the fifth.My problem plant is growing outdoors 52 deg.north under a tree hedgerow.
When I moved them from the window to the spot I only took a small trowel and hadn't prepared the site(last minute decision on plot location). I could only dig 12" round and 8"deep holes and filled with a good soil mix.I was thinking of getting a garden fork up there and loosening the soil uner the plants.....good or bad idea?
Edited by Wulf, 29 July 2010 - 05:40 AM.
Posted 12 November 2010 - 04:29 AM
Posted 15 November 2010 - 02:20 AM
Posted 16 November 2010 - 11:53 AM
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