Is this a sign of Ph problems? Or light burn?

  • Thread starter Custom45
  • Start date
  • Tagged users None
dextr0

dextr0

1,608
113
So could simply removing the softener solve the problem lol? =P
I’m also totally against advising anything other than ro myself personally I’ve seen and had too many problems when starting with other water sources.
 
Last edited:
Custom45

Custom45

59
18
Cheers for the replies. Coco is 70/30 Coco perlite mix (buffered).

Bottom of pots we're still quite wet last night, but felt like they needed watering further up, I just gave them a litre. Went light on the a+b nutes (20%) but added some calmag and some epson salts, ec was 1.6 (start of week 5), pH was 5.9.

Worth noting that problem with brown patches on upper leaves hasn't really got any worse over last 4-5 days. I'll keep adding the calmag to every water and a little epson salts once a week.

I read Aquamans watering guide, it suggested watering quite frequently though, but my work/home life makes that difficult, watering once a day or every two days (what I've been doing) is much more practical.

To be honest this has become a bit of side issue (although still important to get sorted) since the discovery of spider mites. Trying to get those pricks under control or it's game over anyway.

Sprayed See ya Mite (couldn't find the stuff OldManGrower recommended) but hasn't been effective. Last night out up 10 sachets of predator mites and ordered a pot of the more aggressive predator mite, so hoping they'll do their job, but they have mixed reviews.

Nice plants dextr0!
 
Custom45

Custom45

59
18
I wonder if feeding with softened water is causing problems, like I say though I often forget to top upmwoth salt tablets, so it's not usually 100% softened.

Next grow I might go with bottle of mineral water on one plant, to see the difference.
 
dextr0

dextr0

1,608
113
Cheers for the replies. Coco is 70/30 Coco perlite mix (buffered).

Bottom of pots we're still quite wet last night, but felt like they needed watering further up, I just gave them a litre. Went light on the a+b nutes (20%) but added some calmag and some epson salts, ec was 1.6 (start of week 5), pH was 5.9.

Worth noting that problem with brown patches on upper leaves hasn't really got any worse over last 4-5 days. I'll keep adding the calmag to every water and a little epson salts once a week.

I read Aquamans watering guide, it suggested watering quite frequently though, but my work/home life makes that difficult, watering once a day or every two days (what I've been doing) is much more practical.

To be honest this has become a bit of side issue (although still important to get sorted) since the discovery of spider mites. Trying to get those pricks under control or it's game over anyway.

Sprayed See ya Mite (couldn't find the stuff OldManGrower recommended) but hasn't been effective. Last night out up 10 sachets of predator mites and ordered a pot of the more aggressive predator mite, so hoping they'll do their job, but they have mixed reviews.

Nice plants dextr0!

Thanks man I trying really hard to get this right. I got tired of having leaves die off and watch plants that I knew would be beautiful preform ok. To think I just needed calmag. It’s really humbling experience to me.

The reason frequent irrigation is
wanted:

What Happens to the Water and the Salt?​

When you add nutrient solution to the coco, you are adding both water and salts. To understand how EC changes between fertigation events, it is important to consider what happens to each. Remember, plants do not absorb nutrient solution “through a straw” or “like a sponge”. Water and salts (fertilizers) are taken up by the plant separately. Under normal conditions, water is removed about four times faster than salts are absorbed. As a result, the EC of the nutrient solution in the media will rise between fertigation events.

Where Does the Water Go?​

The Plant: Plants absorb water through osmosis leaving increased concentrations of salt in the nutrient solution in the coco. Plants also absorb nutrients and thus lower the quantity of salts in the solution. However, they remove the water much faster than they remove the salts. The vast majority of this water moves through the plant and is lost through transpiration. The water that goes to the plant raises the EC of the nutrient solution in the coco.

Evaporation:
As water sits in the pot suspended in the coco between fertigation events it is constantly evaporating. The water that is lost to evaporation causes EC in the remaining nutrient solution to increase. Evaporation raises the EC of the nutrient solution in the coco.

Because of transpiration and evaporation, the EC in the coco is lowest immediately following a fertigation and “Peak EC” occurs just prior to the next fertigation event. The fertigation events themselves are responsible for lowering the EC in the coco. It may seem counter-intuitive to lower the level of salts by adding nutrient solution, but the process occurs through run-off.

The Run-off: As fresh nutrient solution is added to the coco it pushes out old nutrient solution which had been suspended in the coco. The run-off is not the same water that you are adding in the top. Run-off is higher EC than inflow because it has been sitting in the coco and subjected to the forces of transpiration and evaporation. Run-off carries salts out of the coco. Following each fertigation, the nutrient solution in the coco is closer to the inflow EC. Run-off lowers EC by flushing excess salts.

Water is removed through transpiration and evaporation, whereas salt is only removed via run-off. As a result, frequent fertigation with adequate run-off is essential to manage EC and get the best results from your coco grow!

The Effects of Incorrect EC on Cannabis Plants​

What Happens when EC is Too HIGH​

Plants receive water via osmosis across the membranes in their roots. Water moves through root membranes in the direction of higher concentration. In order for the roots to get water, the concentration of sugars within the roots must be higher than the concentration of salts in the nutrient solution. Plants are adapted to adjust to the osmotic gradient and produce sugars in their roots which raise the concentration and encourage water to enter the roots. However, high EC nutrient solution can easily overwhelm the plant’s ability to raise the concentration of sugars in her roots.

High EC Causes “Nute Burn”: If the EC of the nutrient solution is higher than the plant can handle she will start to struggle to get water. In fact, if the EC gets too high, osmosis can flow in the opposite direction and water is literally pulled out of your plant. This struggle for water and “reverse osmosis” is what causes all of the symptoms that are known as “nute burn” or “fertilizer burn”: wilting, burned tips, crispy dry leaves, leaf curling, slow growth, and eventual plant death.

If you are experiencing even minor signs of nute burn, that indicates that your plant is struggling to pull water against a too high EC. Rather than helping growth by “giving lots of food” you are hindering it by starving the plant of water. “Burn” symptoms should be met with remedial actions. See our tutorial, “How to Manage Run-off EC”.

What Happens when EC is Too LOW​

When the EC of the nutrient solution is too low, plants drink too much water and produce fewer sugars. This is because the concentration of sugars within their roots is in response to the EC of the nutrient solution. When the EC of the nutrient solution is low, plants may initially take in too much water because the concentration of sugars in their roots is higher than the concentration of salts in the nutrient solution. Drinking this extra water does not mean they are taking in additional nutrients. Plants take in water through osmosis and nutrients through separate diffusion and transport processes. Low EC exposes the risk of under-fertilizing because there is necessarily less fertilizer in the water. However, under-fertilizing is only one of the concerns. Plants produce sugars and other good things when EC is correct. They must do this to pull water into the plant through osmosis. If EC is low, plants produce less of the “good stuff”.

What Happens when EC is Not Stable​

When EC is constantly fluctuating, the plants are constantly working to adjust. To receive water through osmosis, plants need to adjust the concentration of sugars within their roots. When the EC of the nutrient solution is lower than they are prepared for, they take in too much water and have to lower the concentration of sugars in their roots. Conversely, when the EC of the nutrient solution is higher than they are prepared for, they cannot take in sufficient water and have to direct their energy into producing sugars to raise the concentration in their roots. When the EC goes up suddenly, plants can suffer burn even at relatively low ECs because the roots are prepared for even lower.

The common practice of interval flushing in coco with one watering of nutrient solution and one watering of "plain", "pHed", or "CalMag" water should not be practiced because it results in unstable root zone EC and forces plants to constantly adjust. Keeping plants healthy and happy requires delivering a nutrient solution with a consistent EC at each fertigation event.

 
Custom45

Custom45

59
18
Thanks, quite an interesting read. I'm currently watering once every 2 days, so perhaps once every day instead would be a slight improvement. My lights on are 8pm-8am, so difficult to water several times a day.

My combination of using softened water with probably a higher sodium content and coco medium are probably causing me problems too, so that'll be corrected for next grow. I think I'm one of these growers that's guilty of using too many nutrients, thinking more is better, but it's not.

Some people skip a nutrient feed every now and again and just water with plain pH'ed water to flush out the old crap, might give that a go. Skip a nutrient feed once a week and do a flush watering instead? I'll measure run off EC when I water next, got a feeling it'll be very high.
 
dextr0

dextr0

1,608
113
Thanks, quite an interesting read. I'm currently watering once every 2 days, so perhaps once every day instead would be a slight improvement. My lights on are 8pm-8am, so difficult to water several times a day.

My combination of using softened water with probably a higher sodium content and coco medium are probably causing me problems too, so that'll be corrected for next grow. I think I'm one of these growers that's guilty of using too many nutrients, thinking more is better, but it's not.

Some people skip a nutrient feed every now and again and just water with plain pH'ed water to flush out the old crap, might give that a go. Skip a nutrient feed once a week and do a flush watering instead? I'll measure run off EC when I water next, got a feeling it'll be very high.

Get drippers Makes it so easy.

I feel like your latching on to bad advice all around.

I’m not advocating doing exactly what it says is bad procedure...in fact I’m advising against it.

What I am advocating is getting cal mag into your coco. It’s a good START to having healthier plants in coco. If your medium is stealing your nutrients (cal mag) your plant is trying to compensate by using other nutrients which starts another deficiency/deficiencies.

If frequent watering is a problem I would grow in soil next time.

Don’t take this as rude I’m just like bro your latching on to the opposite of what I’m trying to share.

Flushing with plain water causes fluctuations in EC. Frequent feeding (even twice a day) helps keep the EC where we want.

Those fluctuations are bad because it cause your plant to waste energy trying to correct the osmotic pressure to receive nutrients or water. This again wastes energy that the plant could use for maybe be using for say buds or growth depending.
 
Custom45

Custom45

59
18
No worries, thanks. I thought maybe flushing occasionally would prevent nutrient build up and would be a substitute to watering occasionally rather than frequently, I know a few growers who flush regularly and water every 2-3 days and do very well so figured it was ok to do??

Like I say I'll start adding in regular doses of calmag and will do it for future grows and look at the type of water I'm using (from a domestic water softener).
 
Custom45

Custom45

59
18
Sorry, yeah I missed the bit in the article at the end where it says why not to interval flush due to causing EC fluctuations. Defo won't be flushing!
 
Custom45

Custom45

59
18
Just checked EC and pH on run off after a watering...

EC 7.5 (3750ppm)
pH 6.2

😟

Both meters were calibrated before and ok.
 
Custom45

Custom45

59
18
When I thought I had some deficiencies I bumped nutes up a bit and fed with EC of 3 a few times, before then 2.5-2.8?
 
Custom45

Custom45

59
18
Was looking at it earlier, I'm way above what they recommend (2.6 last week, 2 this week).

My tap water ec is 0.8, which seems quite high?
 
Mugwort

Mugwort

389
63
Hi all,
Growing a few plants in coco coir, feeding Canna nutes (in week 4.. feeding per 10 litre: 45ml A+B, 25ml Cannazyme, 15ml pk 13/14, 40ml Boost accel, and adding a little TNC Bactorr s13). Temps with lights on 25°c, lights off 20°c. Humidity around 45-55%. Had some browning on leaves and wanted a second opinion on cause. I think it may be light burn.

I'm feeding every other day, each plant is taking about 3 litres. In week 4 of flowering so using pk 13/14. Previously had what I think was potassium deficiency (brown leaf edges and some yellowing) so I started adding a small amount (.3ml per litre) of pk 13/14 in week 2, that seems to have gone away. Also had what seemed to be either nitrogen or manganese deficiency.. lower leaves were yellowing and turning brown. I've been pHing water to around 6.0-6.2, however I checked run off and it came out around 6.3, I read plants take up manganese at slightly lower pH, so lowered to around 5.6 for last few feeds, that seems to have helped, can't see any more leaves turning yellow.

However I've now noticed the brown patches on some top fan leaves. A couple of leaves at first, then a few more, and now even more. It appears to be spreading. Light is a 300w Lumatek Attis led, approx 350mm from plants. Was at 100%, turned down to 80% but problem still getting worse. Think it's too close to the plants. I can raise it, but only by 50mm or so. Is this a light problem and if so whats best course of action? Lower to 60%? I'm worried buds and leaves on plants edges won't then get enough light.

Another thing, I could be wrong, but I'm sure buds have slowed development since I noticed this.

The brown patches look a little yellow in the pictures, but they are browner in real life....
View attachment 1194468 View attachment 1194469

View attachment 1194470 View attachment 1194471

View attachment 1194472 View attachment 1194473

These aren't pollen sacs are they??
View attachment 1194474
I think your instinct that your lights are too close or intensity too high is correct.
Hi all,
Growing a few plants in coco coir, feeding Canna nutes (in week 4.. feeding per 10 litre: 45ml A+B, 25ml Cannazyme, 15ml pk 13/14, 40ml Boost accel, and adding a little TNC Bactorr s13). Temps with lights on 25°c, lights off 20°c. Humidity around 45-55%. Had some browning on leaves and wanted a second opinion on cause. I think it may be light burn.

I'm feeding every other day, each plant is taking about 3 litres. In week 4 of flowering so using pk 13/14. Previously had what I think was potassium deficiency (brown leaf edges and some yellowing) so I started adding a small amount (.3ml per litre) of pk 13/14 in week 2, that seems to have gone away. Also had what seemed to be either nitrogen or manganese deficiency.. lower leaves were yellowing and turning brown. I've been pHing water to around 6.0-6.2, however I checked run off and it came out around 6.3, I read plants take up manganese at slightly lower pH, so lowered to around 5.6 for last few feeds, that seems to have helped, can't see any more leaves turning yellow.

However I've now noticed the brown patches on some top fan leaves. A couple of leaves at first, then a few more, and now even more. It appears to be spreading. Light is a 300w Lumatek Attis led, approx 350mm from plants. Was at 100%, turned down to 80% but problem still getting worse. Think it's too close to the plants. I can raise it, but only by 50mm or so. Is this a light problem and if so whats best course of action? Lower to 60%? I'm worried buds and leaves on plants edges won't then get enough light.

Another thing, I could be wrong, but I'm sure buds have slowed development since I noticed this.

The brown patches look a little yellow in the pictures, but they are browner in real life....
View attachment 1194468 View attachment 1194469

View attachment 1194470 View attachment 1194471

View attachment 1194472 View attachment 1194473

These aren't pollen sacs are they??
View attachment 1194474
I think you were right about your light intensity being too high. I don’t think in metric so I had to convert it. 355 mm is 14 inches. I have a 240W ViparSpectra XS-2000 and I’ve learned the hard way to keep it at least 20 inches above my canopy!
 
GreenMtnGuru

GreenMtnGuru

341
93
Do not use water that has been run through a softener system.

Do not EVER let pots sit in their runoff.

Try to get your watering practices figured out so you can water those things like 3 times a day. Bring your ppm waaaay down.
 
ezenzyme

ezenzyme

489
93
Dexter for the win!! Thanks for taking the time to post real links that contain the information needed. Teach men to fish n all
You can figure all this out with a lil foot work and reading. Quick glance at dexters links gave me info that you seem to have missed.
You need the imput PPM and the out put PPM to figure what the Root Zone PPM is.
You need to change your water source. Yesterday.
You need Cal Mag in EVERY watering for your coco.
You can download apps that tell you your PAR and can take the guess work out of your lights mate.

And jeeezuzzzz thats a high PPM, thats above what i feed outdoors monsters in huge soil!!!

Green is right as well, sitting in runoff is a big no no, have your pots elevated in the runoff trays with drainage in the trays themselves. Your insane PPM needs reigned in, theres a tendency to want to do something more or give something more when there is issues and often that can cause more problems.
Quick quiz the questions are answered in Dexters link. Why would you want to water more frequently in coco?


The above thread by the excallent Aquaman should be your bible! read up, and next time BUFFER your coco to help with the constant cal mag needs.

Post some more pics, how we looking mate?
 
Custom45

Custom45

59
18
Yep, been using softened water the whole time, which goes some way to explaining why my plants and yields are never great.

Also never bother to remove run off after feeding, so plants usually sit in it for a day or so til it evaporates.

Also clearly been over feeding nutes, tested run off pH on plants, ranged from between EC of 6 and 8!

Last night I spent 4 hours and around 100 litres of plain water flushing them. EC down to 1.8-2 range now. Left it several hours and gave a feed with light dose of nutrients, tested then removed run off, stayed 1.8 area.

Will resume normal feeding tomorrow with as regular feds as I can manage, ensuring I always check run EC and pH and adjust follow feeds to suit.

Thanks again for all the help, it's been really appreciated.

Lights have been raised to sit 420mm above canopy. Manufacturer recommends 400-600mm.
 
Custom45

Custom45

59
18
Dexter for the win!! Thanks for taking the time to post real links that contain the information needed. Teach men to fish n all
You can figure all this out with a lil foot work and reading. Quick glance at dexters links gave me info that you seem to have missed.
You need the imput PPM and the out put PPM to figure what the Root Zone PPM is.
You need to change your water source. Yesterday.
You need Cal Mag in EVERY watering for your coco.
You can download apps that tell you your PAR and can take the guess work out of your lights mate.

And jeeezuzzzz thats a high PPM, thats above what i feed outdoors monsters in huge soil!!!

Green is right as well, sitting in runoff is a big no no, have your pots elevated in the runoff trays with drainage in the trays themselves. Your insane PPM needs reigned in, theres a tendency to want to do something more or give something more when there is issues and often that can cause more problems.
Quick quiz the questions are answered in Dexters link. Why would you want to water more frequently in coco?


The above thread by the excallent Aquaman should be your bible! read up, and next time BUFFER your coco to help with the constant cal mag needs.

Post some more pics, how we looking mate?

Yep, the info and links to the Coco for cannabis website have been a massive help, much appreciated dextr0!

As above, did a massive flush light night, EC now a more sensible reading and will be draining after every feed.

Coco I use is pre buffered.

Regarding water source... have an outside water butt fill of rain water that I've never thought of using. Tested it last night, EC of 0.2 and pH of 6.3. Water in it looks clean, but I mixed in a water butt treatment that kills all the nasty shit, it's organic and safe to use water on plants after. I'll use that on 1 of my plants to see how I get on, but confident it'll be a much better source of water. Will add calmag if course before adding main nutes.
 
ezenzyme

ezenzyme

489
93
right on man! your on the right path now! once you use the barrel and get some fresh rain water you need not worry about treatment a 32 gal trash can can be a cost effective water catchment system!
once you get dialed in coco can be a very very productive and rewarding system, i hope your garden turns out well!!
 

Similar threads

C
Replies
9
Views
136
Chubsbudz
C
Deforced
Replies
101
Views
3K
Deforced
Deforced
C
Replies
3
Views
328
CookiesLikeWhoa
C
S
Replies
9
Views
188
SmokinJo421
SmokinJo421
Vb2flat2surf
Replies
17
Views
473
Vb2flat2surf
Vb2flat2surf
Top Bottom