Losing leaves from the lower canopy!

[seedsandsticks]

Hi all,

I haven’t got a camera, so I will try to be as descriptive as I can. I have 4 large plants, which are 2 weeks into flowering, and they are starting to lose some leaves (2-3/plant / day) from the lower canopy. The leaves, which are falling off, show signs of what I think looks like nitrogen deficiency.

The plants were started in a commercial soil mix, I started the seeds in cardboard type (jiffy) pots then moved them to expanded polystyrene cups, then after about 3 weeks when they were nice and stocky (under fluorescent) I moved them to 6 inch pots. They were in All mix from Bio bizz in Holland, and were fed either pH-adjusted water or a very dilute food solution (1/10th of recommended) for the first 4-5 weeks. Then they started to show signs of wanting food (leaves loosing colour from the margins on the older growth) so I increased the food strength (bio bizz grow) and soon caused problems for the new growth. This started to grow very yellow so I assumed I had caused a build up of salts and after flushing this appeared to stop and the leaves returned from their very yellow state to become healthy(ish) green leaves (if a bit scarred).

At around 6 weeks when they were around 0.8 metre tall and looking very healthy and bushy they were re-potted into 10 L containers and they around a week later went into 12/12 (400 HPS, room 1M*1M*2.5M, Lti extractor (100mm 175/M3) 2 circulating fans, flower at night, measuring temp and RH accurately and conditions OK).

I was aware of the growth spurt and the need for N so I continued with the grow food and even went up to somewhere around the recommended dose (whilst adding trace amounts of Bio Bloom((0.5ml/L)) and top max ((Bio bizz bloom stimulator I think again only 0.5ml/L), I was also using superthrive and H2O2.

The plants (2 Sweet tooth #3 and 2 blockhead) are now around 1.3 M and although the majority of the plant looks very healthy (no burned leave tips and a lush green, especially when away from the HPS and viewed under incandescent light), the extremes of the lower canopy (where the sun don’t shine!) are not so healthy and I find the odd leaf is on the floor when I open the door each time. These leaves still have some colour in them so I assume the plant hadn’t completely finished with them and they were not supposed to fall off. They do show signs of deficiency though and as it was just the lower leaves which were suffering and ‘cos of the pattern of the discolouration I think it is nitrogen deficiency.

This is my first grow and I was expecting it to be a slow learning process (especially in soil). I have probably made so many mistakes (under fertilisation/over fertilisation and excess or lack of water leading to stress), that it would be hard to determine the culprit from so many candidates.

For the past fortnight whilst they were stretching I have been giving them ~1.5-2.0 Litres daily (or twice every 3 days) of a mixture containing 2-3 ml grow food/L, 1ml of bloom food/L and 1ml of Top max, 1 drop superthrive/L and ~ 0.1ml 27% H2O2/5 L in water adjusted to pH 6.5

It the typical new grower fashion I am not sure whether to flush them (‘cos it looks a bit yellow/deficient at the bottom)or feed them (‘cos they seem to be growing well). Any advice which may help me limit the damage would be greatly appreciated.

Could the leaves just be dying off due to lack of light at the bottom of the canopy? There really is no light down there, I mean its hardly dark but if you look up through the canopy towards the light you can see the canopy effectively utilises the all of the available light and shades the lower extremes.

Cheers

seedsandsticks

[StonedBrittania]

S&S,

I probably pick 3/4 dead/yellow leaves off the bottom of my plant everyday, i've put this down the the fact they ain't getting much light down there. I'm not too worried about that, should I be?

Cheers

[Rastafarout]

high,

are you overfeeding or over watering?

these both cause your symptons.

ive never heard of a healthy plant dropping its leaves in the way you describe.

good luck

http://www.uk420.com/cultivationfaq/index....php?op=view&t=7

someone sent me this when i had probs and asked a question,i hope it helps you out.

[Sal]

Hi

Only a novice myself But from what your saying S&S it could a combnation of both light and n / def.

I also use BioBiz products but i use the stated dose ie 20 to 40 ml per litre starting at the lower end of the scale first. BioBiz grow and bloom have a relitvely low NPK. The build up of salts you describe could of been mag def is ( a recoring problem in allmix )

as you dont seem to have given corse for toxic salt build up your flushing might have unlocked the mag and thats why growth got better . A dose of epsom salts sorts the mag def out if you look at the faq the stated dose is there

I am by no means an expert this is just my conculsion of what i think to be right

Edited June 16, 2003 by saldo1

[seedsandsticks]

Thanks everybody,

Niceone, StonedBrittania, that has made me feel a bit better. Hopefully I’m being paranoid, wouldn’t be the first time.

saldo 1, I had seen some information indicating there may be Mg deficiency problems reported/associated with Bio bizz and I was wondering if this could be the problem. I will get some. When I suspected toxic salt build up I also had Mg deficiency in mind, as the symptoms seemed very similar from the pictures and descriptions available. Found some for £6.60 for 500g with some company my firm orders stuff from, so I’ll slip it on the company order.

It is funny you should say that Rastafarout, I was reading that trouble shooting guide this morning. I think I may be over watering as I only let the pots go light about twice a week and the rest of the time

I feed them regardless of pot weight. I have read they don’t like arid conditions, but I don’t know how long a pot needs to be light (and the soil to have broken away from the sides of the pot), before the conditions could be classed as arid.

I have also read about the dangers of root damage from over watering and that it is better to let them indicate they need water by drooping leaves.

So I’m never sure what to do.

I often see that they have grown (stretching) and I convince myself they have eaten all their food and that unless I fill ‘em up with everything I’ve got, then they wont get the chance to make the most of the next 12 hours growing.

Despite this I don’t think I’m giving them too much food (fertiliser) though.

Do you let your pots go light?

Cheers

seedsandsticks

[Sal]

When to water ?

Thats a dilema i think we all have when starting off my first grow i overwatered the second one i might have left to dry out to much which can also cause probs ie roots getting damaged but i always wait til the pots are light as you will know yourself there is a big difference in weight. Also i remember OT telling me that it was vertuly impossible to overwater in allmix because it has such good drainage.

My method of watering is as follows water plants till run off apears in saucer leave for no longer than 10 mins if water is still in saurcer i know theyve had enough if saucer is empty i repeat process. Your plants will tell you when they have had there fill by not taking up anymore water from the saucer. This is all knowledge which i got from thease forums and it works.

Happy Gardening

[seedsandsticks]

Thanks saldo 1,

That's what I'm going to do then. I read the post about purple stems and got OT 1's advice about the watering and it all makes sense. I also found the fert advice very relevant. I shall start reading the posts a bit more!

Cheers

seedsandsticks