what's happening to my 2 weeks old baby...

[420amsdude]

Hi all, thankfully I found this forum while browsing for a lil help with my baby plant... 3 days ago I noticed that a couple of the leafs have yellow spots on them and now I noticed that the new born leafs are coming yellowish... I couldn't find the reason that is causing this so perhaps someone experienced maybe be able to help me on here... these are the conditions I've been growing it on:

pre-lightmix soil I got at the growshop, growing it under a 400w master son-t pia philips bulb with a reflector. I use bottled water with pH 6 to 7 tops. the temperature in the closet is a steady 27 degrees (80F) sometimes it gets a degree higher or lower but it's not for long. the first week I had it under light 24 hours a day but 4 days ago I started to do 18/6 lighting, and after I changed the lighting (6 hours of darkness overnight) I noticed that way the temperature at night in the growcabinet gets around 18 degrees (64F) because the light is off, when the light was on 24h it was a steady 27 degrees always. yesterday I got a fan to help with the airflow.
everyday I spray water around the cabinet to help increase humidity to around 60% but most of the times it's around 40% (since I added the fan I noticed that it's steady around 50% but I have seen 30% before but not for long cuz I would spray water around, I use a fine mist sprayer)

I think I included everything need, please let me know if there is anything else you need to know to diagnose my problem.

ps.: the smaller plants are 1.5 weeks old, I also noticed that some yellowness to it but not a lot.

420amsdude Reviewed by 420amsdude on 05-15-2010. what's happening to my 2 weeks old baby... Hi all, thankfully I found this forum while browsing for a lil help with my baby plant... 3 days ago I noticed that a couple of the leafs have yellow spots on them and now I noticed that the new born leafs are coming yellowish... I couldn't find the reason that is causing this so perhaps someone experienced maybe be able to help me on here... these are the conditions I've been growing it on: pre-lightmix soil I got at the growshop, growing it under a 400w master son-t pia philips bulb with a Rating: 5

[Rusty Trichome]

Hi all

Hello

pre-lightmix soil I got at the growshop

Huh...? Is this a peat based mix? (potting soil) Is it pre-fertilized or ph buffered?

growing it under a 400w master son-t pia philips bulb with a reflector.

HPS? What distance from tops? The seedlings can't yet handle the lumens and heat like the larger plant. I'd raise the larger plant 6 inches or so (15 to 20 cm) and the light too if necessary. My 400w batwing I was keeping at about 12-16 inches,(30 cm?) more if necessary because of heat. My 400w glass enclosed hood was at 10-12". (25 cm?) For seedlings, about 24 inches. (60 cm?)

I use bottled water with pH 6 to 7 tops.

Best to keep your ingoing ph as stable and consistent as possible. Growth and nutrient uptake issues if not. What's wrong with your tapwater?

the temperature in the closet is a steady 27 degrees (80F) sometimes it gets a degree higher or lower but it's not for long. the first week I had it under light 24 hours a day but 4 days ago I started to do 18/6 lighting, and after I changed the lighting (6 hours of darkness overnight) I noticed that way the temperature at night in the growcabinet gets around 18 degrees (64F) because the light is off, when the light was on 24h it was a steady 27 degrees always. yesterday I got a fan to help with the airflow.

Try and keep the gap in temps as tight as possible without getting all anal and obsessive about it. I live in the desert, and my plants handle the heat of summer better than they handle the cold of winter. There are upper limits though. Me...I'd raise the temps at night a tad. Easier than trying to cool off during the day. This is insight, not a recommendation.

everyday I spray water around the cabinet to help increase humidity to around 60% but most of the times it's around 40% (since I added the fan I noticed that it's steady around 50% but I have seen 30% before but not for long cuz I would spray water around, I use a fine mist sprayer)

Some folks fret over low humidity. In my region, low humidity is less than 8%. But if properly watered, they can usually provide their own moisture, (roots) and the soil evaoprates moisture, raising humidity a tad anyway. Only time I ever spray is to correct deficiencies.

[420amsdude]

Hello

Huh...? Is this a peat based mix? (potting soil) Is it pre-fertilized or ph buffered?

it's peat based mix and it is pre-fertilized

HPS? What distance from tops? The seedlings can't yet handle the lumens and heat like the larger plant. I'd raise the larger plant 6 inches or so (15 to 20 cm) and the light too if necessary. My 400w batwing I was keeping at about 12-16 inches,(30 cm?) more if necessary because of heat. My 400w glass enclosed hood was at 10-12". (25 cm?) For seedlings, about 24 inches. (60 cm?)

yes it's an HPS lamp and I have raised it a little over 24 inches from the top but the new leafs are being born with some yellow spots still.
the pH in the tap water in holland is way too high (8.6) so I use bottled water for that reason.

Best to keep your ingoing ph as stable and consistent as possible. Growth and nutrient uptake issues if not. What's wrong with your tapwater?


Try and keep the gap in temps as tight as possible without getting all anal and obsessive about it. I live in the desert, and my plants handle the heat of summer better than they handle the cold of winter. There are upper limits though. Me...I'd raise the temps at night a tad. Easier than trying to cool off during the day. This is insight, not a recommendation.

Some folks fret over low humidity. In my region, low humidity is less than 8%. But if properly watered, they can usually provide their own moisture, (roots) and the soil evaoprates moisture, raising humidity a tad anyway. Only time I ever spray is to correct deficiencies.

...

[Rusty Trichome]

Have you checked the ph of your bottled water? If bottled locally, chances are it might have the same ph as your tap. Just cleaner. Still worth checking, regardless. 6.3 to 6.8ish ph recommended.

With pre-ferted mediums, sometimes you have to ride-out the nutrient assault on the youngsters. Not optimal for seedlings and clones, but they usually acclimate over a couple of weeks. Hold-off on additives or extra nutrients, at least a few weeks. You have to let the nutrients burn-off a tad. But usually by then they'll need a transplant, and will get more nutrients from the additional pre-ferted soil. After transplanting, again, watch their reaction, and no nutrients till necessary. Might develop a micronute shortage, depending on which nutrients you medium includes.

Looks like ya need a little practice with the quote and answer thing. I almost thought you forgot to answer. Once you've hit the quote button and got the reply screen, you make sure the 'open quote' tag starts the line, then the text you want to quote, then the 'close quote' tag, then answer the quote. You can break-down the quotes into individual sentences or paragraphs by copy-n-pasting the open and close quote tags. Repeat as necessary, and check the quote using the 'Preview Post' button.