First post, first grow, first problem!

[NumptyDumpty]

Hi there all,

This is my first post so to begin with may I congratulate the contributors to this board - it is an excellent resource and also a great read.

I'm hoping to tap your collective wisdom to get to the bottom of my first grow problem. I've been lurking for a while and have searched extensively and discovered that it could be a few things but I'm not sure exactly.

The plants are all 16 days old from seed.
They are growing in a John Innes based seed mix which is very nute light (almost none I believe) - they were germinated in the pots in which they still reside (10cm wide).
I'm watering with 1ounce of mineral water a day - pH=6.2-7 EC=0.1
The temperature was high at around 30*c for the first week after sprouting but is now controlled to 25*c stable (day and night).
The RH is very low ie less than 30% - I have tried to raise it with buckets of water in the room but to not much avail.
The room is 1m2, with good ventilation.
They have been under a 400w MH since sprouting at about 20inch above the plants.
The strain are satori and feminised cheese - both strains are showing the same symptoms, some plants more than others.

I plan to repot into larger pots very soon and they will go into a John Innes no2 mix with added mycorrhizal fungi, nothing else.

The problem;
Starts when the tips of the first two true leaves began to go a shiny deep green. The edges curl upwards slightly and the leaves feel dry and crispy after a few days - this spreads slowly towards the base of the leaf. The leaves then show some golden brown freckles and sort of delaminate - crumbling apart at the end. New growth seems strong and healthy but I'm concerned that the new leaves are beginning to go shiny and darker green at the edges.

I cant yet post pictures (or am too dumb to work out how) but you can see them in my gallery.

My feeling is that this may be related to the low humidity - almost as if the leaves are being freeze dried on the plant - but hey, I'm a noob and a Numpty so what would I know!

I'd much appreciate any feedback on this.

 

[Jerry Maine]

Can't help you with the plant but to post pics just right click on the pic, copy image location, and then paste that between

Here's one of the pics from your gallery

 

[NumptyDumpty]

Hi Jerry and thanks for the info but it seems I am not allowed to put my pics up yet (I get a message that says "post contains one or more URL's, please remove before reposting." or somesuch - but the picture you have posted is probably the best illustration of the problem.

 

[tree&leaf]

The plants are all 16 days old from seed.
They are growing in a John Innes based seed mix which is very nute light (almost none I believe) - they were germinated in the pots in which they still reside (10cm wide).
I'd much appreciate any feedback on this.

Hiya Numpty,

Therein lies the clue to your problem. Everything else you're doing sounds fine to me, although I don't like that light so close to new sprouts, they don't need that much light in their early days.

The bottom line is, they're running out of the nutrients in the soil, John Innes seedling mix carries very few nutrients as it is and what there was have been exhausted and the plant is beginning to cannibalise existing nutrients (mainly Nitrogen, which is a mobile nutrient meaning it can be moved) to support new growth. That's why you're seeing the tips of your leaves beginning to turn yellow and shrivel as they die.

The solution is easy - repot them into some John Innes No2, (1L, 2L pot) which is designed for middle vegetative growth stages. Please ensure correct drainage in the pots and learn the 'wet dry' watering method.

You should aim to repot up in stages until its final flowering pot as each repot develops a larger rootball. Large rootball mass = large healthy growth above the surface and maximised nutrient and water uptake - important in flowering when after the first 3 weeks or so the roots stop growing.

Good luck, particularly with Satori - fabulous plant and smoke.

 

[NumptyDumpty]

Hi T&L,

Thanks for the response. I figured that this was a possible cause and that it was time to re pot, but because the leaves were going deep shiny green I was unsure that it was a deficiency in N. So you think the low humidity has little bearing on the problem? - I'm glad if that's the case as I have no ready method for upping it and I guess as the plants grow larger the increase in transpiration will cure the low RH.

As for the lights I was all spent out (including the wife's patience!) and so had to go with the MH right away, I plan to get some CFL's for next time.

I'm basically trying to follow the advice given by Mandala on the grow including the re-potting in stages and minimal fertilisation - just letting the good earth (or JI in this case) do its job - which leads me to another question; would you add any vermiculite/perlite to the JI compost (mandala suggest not and I wasn't planning to) or should I be fine if I just go with 100% JI compost and only water when the pot is light? What is the wet-dry method of which you speak? Sorry to bombard you but I've read a few of your posts and feel that you have a very good knowledge of gardening!

I'm very much looking forward to tasting the Satori (far more so than the cheese, but I also wanted some heavy mong-weed and cheese looks like it'll fit that bill), but also not counting chickens etc as I know there is a lot that could go wrong between now and then

Thanks again.

 

[Queso45]

I'm not an expert, but I have grown Big Buddha Cheese and have learned a few things about the strain. I've learned that cheese barely eats anything.

I don't want to sound like I'm saying the previous suggestions are wrong, but I want to suggest maybe thinking of an additional solution. I think it is more likely that the mineral water you are using is causing these problems. Maybe consider after you transplant into bigger pots ---to water with RO or good tap water.

Just my two cents..

 

[NumptyDumpty]

Hi Queso,

One of the things I considered was that the mineral water I've been using may not contain enough mineral salts/micronutrients (EC 0.1), but I was using it as at the time I had no accurate way to measure the pH of my tap water. I've now got a pH meter and discover that our tap water is pretty good, its hard with a pH at around 7.7 and EC of about 0.4, it contains a small ammount of iron, manganese and nitrate so I'm going to switch to that and use vinegar to adjust the pH down.

Thanks for your insight on the cheese - I'm hoping that a repot to richer compost will do the trick.

 

[tree&leaf]

So you think the low humidity has little bearing on the problem?

Low humidity may have a bearing on the deep green leaf, but it won't be the cause of the leaf yellowing.

It's worth understanding how humidity affects the growth of a plant. Humidity is essentially a measure of how much water the air holds and it's relative - relative to the maximum amount of water the air can hold at a given temperature as a ratio to the actual amount of water the air is holding. So when people talk about 60% Relative Humidity, what theyre actually saying is, the air is currently holding 60% of the maximum amount it can hold at this temperature.

Hotter air can hold more water than cooler air and this is why RH goes up as the air cools and the reason humidity levels tend to be much higher at lights out than it is during lights on and precisely the reason people need to monitor this with a max/min RH and temp meter. This becomes particularly important in flowering as high humidity levels (over 60%) fosters fungus and mould growth.

Relative humidity also influences the opening and closing of the plant stomata (the little holes on the underside of a leaf) whose main purpose is to intake co2 and expire o2, but it also regulates water transpiration. Water transpires very slowly into high RH and faster into low RH or drier air. When water levels in the plant are very low (or RH levels very high), it will close the stomata altogether to pevent any further water loss and dehydration. If this happens then the plant can no longer intake co2 - which is the key building block of photosynthesis and plant growth halts altogether.

So what you want ideally for maximum growth potential is neither high nor low RH, which is the optimum levels of 40-60% Relative Humidity that Canna thrives in. Low humidity 10-30% simply means that the plant transpires water faster and therefore uses more water. Personally I prefer RH at or around 20-40% in flowering to prevent mould and fungus from forming.

So as you can see, low RH, will not cause your leaf to turn yellow!

would you add any vermiculite/perlite to the JI compost (mandala suggest not and I wasn't planning to) or should I be fine if I just go with 100% JI compost and only water when the pot is light?

A small amount of perlite is beneficial - it helps drainage and also helps to retain water and nutrients for slower release but certainly not to the madness levels I see some people using it on here - 60% soil to 40% perlite? Why? To cut a soil back for seedlings if it's too hot in nutrients - yes, fine, but not for anything other than seedlings, because all you're doing is denying the plant those extra nutrients which will mean you'll either have to repot earlier than you should or start having to use expensive liquid nutrients.

The best grows in my opinion are the ones which use the minimum of liquid nutrients and if your repot sequence is correct, you really should only need to feed liquid nutrients in the last 4-6 weeks of flowering, primarily because at that stage in flowering you cannot repot the plant into a fresh set of soil. The more you let nature do the work for you - the better the end result.

So, a small handful of perlite into a 2-3L pot fine, but no more than that. Vermiculite serves a similar but slightly different function to perlite as it can hold a lot more water and nutrients on its surfaces than perlite can and therefore can be helpful in stretching the time frame between waterings. Even if I needed to do that still I wouldn't use much more than 10-20% vermiculite and would put it in a bigger pot so I wasn't losing soil nutrients.

With todays modern Multi purpose composts and the John Innes range you use, as long as they're reconstituted correctly from their compacted compressed transport form into light fluffy soil with no large lumps or stones or twigs, you should not have any drainage problems, and therefore do not require the huge amounts of perlite that old growers used with poor sandy or clay based soils that tend to compact when watered.

What is the wet-dry method of which you speak? Sorry to bombard you but I've read a few of your posts and feel that you have a very good knowledge of gardening!

The wet/dry method of watering is basically watering to saturation (with a little run off out of the pot, not too much or you'll wash out nutrients) and then waiting till the pot feels 'dry' before watering again and then repeat the procedure. The way of testing this is to simply lift the pot and feel its weight, if it feels 'light' its time to water again. Fill a plant pot full of fluffed up soil to the top and lift it and feel its weight. Now saturate that pot with water till it runs out the bottom, now lift it and feel its weight - see the difference? One will weigh a lot more than the other and understanding these weight changes will tell you when its time to water again. After a while it will become second nature and you'll never have to wonder whether you're watering your plants correctly ever again.

I'm very much looking forward to tasting the Satori (far more so than the cheese, but I also wanted some heavy mong-weed and cheese looks like it'll fit that bill), but also not counting chickens etc as I know there is a lot that could go wrong between now and then

I'll look forward to hearing your views on both. Personally I think Cheese is highly over-rated (it is after all, just a Skunk #1 pheno) and for a variety that was intended to be distributed via clone for free to all that wanted it, having to buy it in seed form rather sticks in the craw of many people, myself included. Those people who got a clone of cheese were given that clone on the specific instructions to pass it on for free - sadly the selfish twats now don't do it.

Sadly, the Canna world and industry has got greedy. In any case, in my opinion, Satori blows it out if the water. Pay little attention to people going on about how wonderful cheese is, most of them don't even have the original pheno anyway.

Just my opinion, and I'm sure many will disagree as they usually do

 

[NumptyDumpty]

Thanks again for your considered reply T&L.

I'm in agreement with the "less is more" ethos with regards to liquid feed in a compost based medium, and this is in part why I decided to undertake this venture - there's so much overpriced, adulterated, shitty smoke out there I cannot countenance paying for it any longer.

With regards to RH; I'm reassured by your explanation (plant anatomy - its all coming back to me now, I undertook half of a degree in biology many moons ago!), I'll stop worrying about that for now.

Anyway I decided to repot a little earlier than I had expected and did so tonight. I skipped on the perlite as per mandala's faq and will just water very carefully, but I think I've got the hang of the wet dry method as this is pretty much what I've been doing thus far. I put them into 8" pots (2.5l i think) with JI no2; what surprised me was the enormous root growth in such a short space of time - they had reached the edges of the pots and I'm very encouraged by this. Fingers crossed this'll sort the yellowing out.

I wasn't aware of the history of cheese before I got the seeds - they were the cheapest feminised I could get and my grow is so small scale I wanted a fairly good guarantee that I'd get a couple of ladies pop up. My main interest is in the Satori, which from all I've read is a fantastic plant and I'll certainly keep you posted on the results.

Thanks again.

 

[MynameStitch]

Your problem is simple, with the mixture you are using, it's mostly peat based mixture, check the pH.

I honestly think the biggest problem like queso has stated IS the MINERAL WATER.

GET rid of it; it contains sodium which is very bad for plants, causes stunting slow growth and it causes vascular breakdown inside the plant causing moisture issues and such.

BUT ANotehr thing I see, how close is this 400 watt HPS? I see tips curling upwards a bit which means they can be getting more heat. I f I were you I would put them under compact fluros or a metal halide.

Those leaves are either A) caused by the dry heat the 400 loves to produce
B) pH which you have not checked, I don't think it's the problem; but it's very important to always check.....
C) mineral water is bad; use tap water as long as it's not way too hard.

Since your humidity is that low, get a humidifier or get a wet towel put it near the plants, not soaking wet, but wet, this will keep humidity near the plant, but not cause mold since your humidity is that low.

 

[NumptyDumpty]

Hi Stitch and thanks for the reply,

To answer a few of your questions;
the plants are under MH as opposed to HPS, the light is about 20" above the canopy, temperature is at a constant 25*C.
The compost I'm using has a pH of 6.5 and the water is between 6.2-6.5 (mineral water that is), the mineral water also contains less sodium than our tap water.

Here is the info on my tap water;

Hardness Level Hard
Hardness Clark 18.13
Aluminium 7.9 μgAl/l
Chloride 36.36 mgCl/l
Chlorine 0.28 mg/l
Conductivity 541.24 μS/cm at 20°C
Fluoride 0.2 mgF/l
Iron 9.95 μgFe/l
Manganese 1.6 μgMn/l
Nitrate 16.01 mgNO3/l
Pesticides 0 μg/l
pH 7.73 pH Value
Sodium 25 mgNa/l
Plumbing Metals
Copper 0.03 2.0 mgCu/l
Lead 1.96 25 μgPb/l
Nickel 2.96 20 μgNi/l

What do you think to the quality of it? Good enough to grow with (pH adjusted down with vinegar)?

Thanks for the help.

 

[MynameStitch]

Sodium in the tap water is natural compared with the sodium that is in bottled water; 2 totally different things........

Tap water is fine, just let it sit out 24 hours before you use it.

I would slightly raise it just to be sure, a lot of strains have different tolerances to heat and strong of light.

I would give your plant a good flush with tap water and go from there
Also vinegar is not a good pH adjuster as it;'s not stable; does not stay stable long enough to keep the way you want too; you will need to get some pH down from a hydro shop or pet shop and ensure it says safe to use for plants.

Sulfuric acid which is also known as battery acid, from a shop is ok to use even though it sounds crazy. Not taken from a battery, stuff you buy from a store...... just sulfuric acid. Small amount needed.

 

[tree&leaf]

Tap water is fine, just let it sit out 24 hours before you use it.

And let all the dissolved oxygen evaporate out so there's none or little for the rootzone? That's not a very good suggestion, in my opinion. And the tiny amounts of sodium you're removing by doing this cause no harm.

I would give your plant a good flush with tap water and go from there

Another suggestion I do not recommend, as that simply washes out any nutrients that may remain in the soil as well as removing any potential dissolved salts, as well as potentially water logging the soil.

Flushing is usually the last resort by anyone who cannot figure out what the problem is.

The problem with his plant is simple - its run out of nutrients, because the soil the plant is in never had many nutrients to begin with.

Water quality is important, particularly hard water that contains high levels of dissolved salts, but mineral water does not contain high levels of dissolved salts and would therefore not cause that kind of problem within that timeframe.

Also, I do advise the use of sulphuric or any acid as a ph adjuster in compost soil grows - the acid buildup over time does contribute to the TDS content of the root zone and can also over time kill and damage the beneficial bacteria and funghi required for chelating down organic nutrients and increasing plant metabolism like myrorhizzal.

In situations where ph stability is critical as in hydro, fine, but soil/compost grows do not require precise ph adjustment as compost is largely self buffering and comes with its own ph value, well within the range of acceptable nutrient uptake.

 

[NumptyDumpty]

Hi T&L,

I get the feeling Stitch meant leave the water standing to get rid of the chlorine but i could be wrong. I usually "bubble" my water before watering using a hand pump or shaking to increase the levels of dissolved oxygen - whether this is effective or not I have no idea, but it makes sense that it should from a physics point of view.

I certainly have no intention of flushing the soil nor adding acid to it. I'm only adjusting the pH of my water, using the vinegar in tiny ammounts (as suggested by mandala mike) and I'm not concerned about the pH of the medium itself, which as you say should pretty much take care of itself, and will be replaced in two or three weeks with fresh JI no3 ready for flowering.

What do you think to the quality of my tapwater T&L (see above post) - is it too hard, and if so what problems might that present and how can I mitigate them.

After the re-pot I've found that the RH has also increased due I'm sure to the larger surface soil area from which water is evaporating.

Anyways, thanks for all the input - I'll keep you posted as the the condition of the plants in the new pots over the coming days.

 

[tree&leaf]

I get the feeling Stitch meant leave the water standing to get rid of the chlorine but i could be wrong.

Yes, that would be the reason for letting water stand 24 hours, to allow some unwanted dissolved solids to evaporate - but as I said, it also allows the dissolved oxygen to escape as well - which is the greater of the two evils. Bubbling and invigorating the water before watering does help to restore some of that lost oxygen as you rightly point out. Another way to add more oxygen is to water with a fine rose watering can - the little sprinkles of water not only help penetrate the soil surface but also push more dissolved oxygen into the root zone at the same time. It mimics the action of rain.

What do you think to the quality of my tapwater T&L (see above post) - is it too hard, and if so what problems might that present and how can I mitigate them.

It's not ideal - it contains too much sodium, which after a while will build up and start locking out nutrients, the most notable being Mg, but it depends on how you grow. Salt levels only build up to toxic levels after the plant has been in the same pot and soil substrate for some time - most notably in flowering, where you add to existing salt levels with nutrient and fertilisers.

You shouldn't have a problem in vegetative growth - simply because the plant does not stay in one pot long enough for salt levels to build up to toxic levels and, you're not adding to it with nutrients, the main exception to that of course is when you keep mothers.

A lot of this is also strain dependant and also depends on soil/compost quality, nutrient and fertiliser quality, whether they're organic or mineral/chemical based and so on. Some varieties are more sensitive to salt levels than others, and some varieties are not as efficient at metabolising nutrients as others. This is why pretty much every time you grow a new strain, you almost have to reset your knowledge bank back to zero and start again - as each variety has its own strengths and weaknesses and don't all grow in the same way.

You really have to grow out a particular strain many times before you begin to understand what it likes and what it doesn't like. If you're continually growing new strains you'll never get the best out of any of them.

I've done it both ways - grown with hard water like you have and with RO water as well and each method requires a slightly different approach. If you use 100% RO water, then you've taken out all the dissolved salts - as well as useful ones - so those trace minerals will need to be replaced. If you use plain tap water than you'll need to adopt an agressive repot schedule, which is good in its own way because each time you repot up into a larger pot the rootball increases in size and large rootballs = maximised nutrient and water intake, which is effectively what the Mychorizzal funghi you use does - increases the size of the root zone. Another way might be to use 50% RO and 50% tap water, thus reducing down TDS levels but still keeping some of those trace minerals and elements.

There's no real right or wrong way, but only which way works best for your own situation and strain, and to understand that requires experience, experimentation and observation. You're lucky (we all are) in many ways that Mandala strains are relatively easy to grow, have great hybrid vigour and are highly efficient at using and metabolising nutrients. Many strains, DJ Shorts Blueberry rather springs to mind, can be a nightmare to grow and are very finicky about salt levels, nutrients and so on.

After the re-pot I've found that the RH has also increased due I'm sure to the larger surface soil area from which water is evaporating.

Yes, that's consistent with the greater expiration and evaporation of water from the larger pot. The higher RH goes, the more important ventilation and air circulation becomes.