Plant Moisture Stress - Symptoms and Solutions

Hola Uncle Ben

I just took these pics of my plants. The old fan leaves are fine but the tops are cupping and twisting. This freaked me out so I stopped watering thinking the plants were overwatered. The moisture in the pot was a little low though. What is wierd is that the twisting is only occurring on the plants in the center of the room under the 1000w lights. The heat is not the cause as the light is almost 2.5 ft above them and is not hot to the hand at canopy level.

This is the first time this has happened. Last grow went off without a hitch, same strain same light setup watering schedule etc.

My first guess is underwatering induced by panic from fear of overwatering since it is only occurring in the newer leaves and some of the bigger newer leaves are a little cupy. Wasnt sure about the twisting though. Any thoughts and help is appreciated?

Hey Uncle Ben,

I have a question. I'm finishing up my first grow right now - coming along pretty darn well (should be done in 4 weeks) and I wanted to start my new grow (super silver haze) right now because I need to flower the plant by june and harvest by the end of august, due to moving.

I have my current plant under a 400w HPS lamp. I also own a MH bulb, but only have one ballast and one grow room.

My question is - Can I germinate my new plant and begin growing it under my HPS lamp on the 12/12 cycle alongside my flowering plant, or will this create problems? I also own a few flourecents, but I would like to veg my new guy under a solid lighting setup. - ...Could I switch the bulb back to MH and continue the 12/12? I'm stuck with how to go about this...

Any suggestions for what to do?

Thanks a ton.

greenthumb111 said:

Hola Uncle Ben

I just took these pics of my plants. The old fan leaves are fine but the tops are cupping and twisting. This freaked me out so I stopped watering thinking the plants were overwatered.

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Hola! Plants look great all in all. Most likely what you've created is dry spots or channels such that the soil is no longer capable of holding moisture, it's an ion thingie. I have found over the years that there is no way I can overwater my plants. Why? Because they have a large enough root system and abundant foliage such that they quickly wick off moisture. The more the foliage, the less chance of EVER overwatering due to the capillary action (negative water turgor) and leaf transpiration. Having said that, you may want to rotate plants in your garden. Overwatering is not the issue, lack of aeration at the root zone is.

The moisture in the pot was a little low though. What is wierd is that the twisting is only occurring on the plants in the center of the room under the 1000w lights. The heat is not the cause as the light is almost 2.5 ft above them and is not hot to the hand at canopy level.

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For starts, heat on the back of the hand is a poor way to gauge anything, it surely doesn't gauge the amount of light a plant is and should be receiving. Like I said, perhaps those plants in the center can't take the heat and/or light and should be rotated out. Increase your watering frequency too.

BTW, you can restore the soil's moisture retention properties by watering from the bottom up. The addition of a squirt of Ivory liquid dish soap into a tub of water will as a surfactant. Set the plant in a tub with sides higher than the pot, run water into the tub, not the pot, and let it sit there for about 10 minutes.

Good luck,
UB

brsweet said:

Hey Uncle Ben,

I have a question. I'm finishing up my first grow right now - coming along pretty darn well (should be done in 4 weeks) and I wanted to start my new grow (super silver haze) right now because I need to flower the plant by june and harvest by the end of august, due to moving.

I have my current plant under a 400w HPS lamp. I also own a MH bulb, but only have one ballast and one grow room.

My question is - Can I germinate my new plant and begin growing it under my HPS lamp on the 12/12 cycle alongside my flowering plant, or will this create problems?

Click to expand...

It depends on genetics and other factors, all you can do is try. Me, I'd wait until after I moved...... but then again you and me have different objectives. I do 20/4 for veg and get my best foliage out of that photoperiod.

I also own a few flourecents, but I would like to veg my new guy under a solid lighting setup. - ...Could I switch the bulb back to MH and continue the 12/12? I'm stuck with how to go about this...

Any suggestions for what to do?

Thanks a ton.

Click to expand...

You can flip any way you want as long as you don't stress the plants by going from a low f.c. to a high one. That will bleach out chlorophyll - not good. If it was my garden, I'd choose the best, most convenient plan regarding light installation, veg your new plants with the flowering ones, pull the them out just before lights-off and place them in some kind of light to simulate long days/short nights. You can do it with normal room lighting, west window, take 'em out to the patio for a sunbath, etc. Contrary to popular belief, HPS is great for vegging, it has plenty of the blue spectrum. I've done the experiments. You don't need to switch to different HID's.

Have fun!

[For starts, heat on the back of the hand is a poor way to gauge anything, it surely doesn't gauge the amount of light a plant is and should be receiving. Like I said, perhaps those plants in the center can't take the heat and/or light and should be rotated out. Increase your watering frequency too.]

THx for the response UB. I watered them and this AM they were perked back up. Whew! Thx again

Hey Ben,

Thanks for the post, good stuff. I have some cupping and tip growing upwards on some plants, not too appealing, but they are my babies. Their medium is rock wool cubes in a deep water culture with a constant drip feed from a Rain-Bird drip emitter, works great. Saw a little algae build-up on some nozzles but cleaned them off. I'm at 800 ppm right now according to my math using Advanced Nutrients, really amazing stuff. I worried about the heat levels off my HPS used for veg (cant afford anything else rite now). Its at 18 inches in distance from the tops now, and seems to be OK. I noticed a few spots on the leaves, very minimal, looks like I fed them a little too much this round (only 3 weeks in). My pH is maintained constantly at 6.0. The roots look fantastic, started them off with GH's Instant Karma.

I want to make sure I am doing the right things before I consider doing something wrong. Obviously we want the healthiest appearance possible and the slight curning on the first wide set of leaves and some on the 2nd sets. Any advice as to what I can to to prevent or stop anything further from happening? I worry about algae and what it can do, but my retailer said I will get algae no matter what I do, I just have to minimalize it.

THanks

Great!

Love the avatar lol.

Great thread helped me a lot with some issues I was having with some babies. Thanks...I sure hope they pull through

wow, i think some one should write a book. Can call it, "Uncle Bens grow guide".

RollinBlunt said:

wow, i think some one should write a book. Can call it, "Uncle Bens grow guide".

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Yeah Ben, you got some good stuff

Thanks for the info!

Glad to be of help!

Ben

Hi Ub, I need the benefit of your xperience!
I started a number of plants from seed about a month ago and they have been exhibiting pretty bad leaf burn for the last couple of weeks. they are about 12" below a 250w bank of florescents and they are potted in specialist compost (which has a 5% base fertiliser). All of them have some leaf burn, and on some of them the foliage is turning yellow! The temperature is 20 degrees c (I have a thermostat regulating the exhaust fan) They are in 2 litre pots, and the largest is about 4" high. I have not been feeding them.
From what you were saying earlier in the thread, it sounds like I might be giving them too much light, but this is my first time round so I'm not too confident in my own diagnosis. What do you think?
Many thanks

Majestic Pagent said:

Hi Ub, I need the benefit of your xperience!
I started a number of plants from seed about a month ago and they have been exhibiting pretty bad leaf burn for the last couple of weeks. they are about 12" below a 250w bank of florescents and they are potted in specialist compost (which has a 5% base fertiliser). All of them have some leaf burn, and on some of them the foliage is turning yellow! The temperature is 20 degrees c (I have a thermostat regulating the exhaust fan) They are in 2 litre pots, and the largest is about 4" high. I have not been feeding them.
From what you were saying earlier in the thread, it sounds like I might be giving them too much light, but this is my first time round so I'm not too confident in my own diagnosis. What do you think?
Many thanks

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Sounds like a watering issue. Is the soil too hot?

Uncle Ben said:

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

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when you say up-can, would that be the same thing as when i take my plants out of the pot. Then taking the blade and cutting the root system apart? If im wrong can you help.?

greengold69 said:

when you say up-can, would that be the same thing as when i take my plants out of the pot. Then taking the blade and cutting the root system apart? If im wrong can you help.?

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"upcan" as in transplant to a larger pot, can. Don't cut the root system apart, only score the roots doing the spin out thingie.

It may be too hot - I'll test it. Will put some pics up next time I get to the internet - they really aren't doing brilliantly at the moment. Its a steep learning curve to be sure... Thanks UB

i put a thread on rollitup to help people,, i found all the info on another site,, people then winged at me for it, although it did help alot ov people on here

ive read the plant moisture stress article lots of times on all different sites a long time ago,,, so i was just wondering if any one winged at u for posting the plant moisture stress article on rollitup UB?

UB, what do you mean, score the roots? Cut a little bit?

+ Rep def a help