Can too much light be harmful 4 small plants?

[dvine]

Can lets say a 250w mh lamp be to much light for small plantsSmall plant (not clones) even if the temprature is correct?

 

[kmk420kali]

No...as long as it isn't hot...you are good-- The only time you can get too much light, is with clones, before they root--

 

[yohomz]

You want to keep it far enough from the tops so that they don't get burned. Keep a 250 mh 12 to 18 inches above your plants.

 

[dvine]

You want to keep it far enough from the tops so that they don't get burned. Keep a 250 mh 12 to 18 inches above your plants.

12-18"... 18-45cm, alright

 

[Guest]

The above posts are right on - it's all about the heat, not necessarily the light or lumens.

One side note and suggestion - you may want to look at using CFL's if possible during the seedling phase. The seedling grows just as well (due to lower light requirements) and your electricity bill will be a little lighter.

Just no sense using a flame thrower to light a BBQ...a match works just as well.

 

[dvine]

at what size should i start using the mh lamp then ?, how tall should they be?

 

[Guest]

as soon as they pop, and it can be 1 inch away as long its cool enough,

 

[NiteTiger]

Yep, heats your issue, not lumens or watts. If things are cool enough, drop it right down on them

On another note, I don't keep my 1kw 18" from the canopy (unless I need to for footprint's sake. Just gotta have that heat under control.

 

[dvine]

How can i messure the temp in the best possible way?, i have one of thouse "in/out" things with a cable and a sensor at the end. Is it a good way to but a small roof over the sensor of lets say aluminium and then try to place it close to the top?

Btw thanks alot for all the awsome help i get here

 

[Merman]

I'm sure many of you have seen this before.....



Yup, its all about heat..... You can almost grow'em up to the glass of your aircooled unit if ventilation is under control.

 

[dvine]

Ok.. then my problem cant be the problem with heat :/ im going crazy atm becouse i have no clue what my problem is, i can try and explain it here so sorry for not posting my problem at the right place.

Space:
* 100*70*200 (cm)
* Temp: 25-27 (mabye some times as high as 30) (celcius)
* Fans: Yes, 2*120mm computer fans

Light:
* Kind of lamp: 1 MH 250w with cooltube + 2 coldwhite florrecent
* Distance: 40cm(mh) 10-15cm(florrecent) (different places)

About the plant
* pot size: about 1L

Vater and nutrients
* nutrient: None, just clean tapwater with a modyfied ph around 6.5-7

Other:
Earth: Good earth i have used before and have getten realy good crops - Mixed with 30% vemriculite
Draining: Hole in the bottom of pot.
Water PH: 6.5-7
Air humidity: 45-60%
Ventilation:175m3/h
floors and so on: Coverd with mylar and white paint
Description of problem: The plants are growing realy realy slow and for some reason start getting yellow/blown at the edges of the bottom leafs and the problem is spreading. Here is a picture.
Seeds: Home made seeds from the strain skunk passion, about 2 year old stored in a darkspace (germinated pritty easy).

 

[NiteTiger]

That looks like a PH issue to me. 6.5-7 is higher than I've ever used. I was always put my PH at 6.

Copy that post over to the Cannabis Infirmary forum and you'll get better feedback. Also, check the stickies for The Complete Sick Plants Guide by mynamestitch, it's a great reference.

 

[dvine]

about the ph... something is realy strange.
Normaly i have 8.0 tapwater and then i add a few drops of ph down (grow) untill the ph gets to about 6, a few days later when i first mix around the water some and then check the ph again it close to 8, like 7.5 or something, realy goes on my nervs

How should i change my ph level of the water in the best possible way to get it to around 6-6.5 and have it staying there ??

(tbh, i think its a ph problem as well so it must be me who just mix it wrong so please help me)


Edit:
Is it possible to lets say take tap water and let it be for 1 day, then right before im gonna water my plants i THEN lower it down to about 6-6.5 even tho 1 day later it will be around 7-7.3?

 

[NiteTiger]

You're in soil, so did you ammend with a PH buffer like lime? Lime is often used as a PH buffer in soil.

Also, I don't mix nutes or do anything until I'm ready to use it. WIth PH that high and that much of a swing, you may want to consider using RO water, which will be a bit more stable for you. Wal-Mart's "Drinking Water" (not distilled) is R/O, and only like $0.68.

Give that a try, see if your PH stabilizes.

 

[dvine]

You're in soil, so did you ammend with a PH buffer like lime? Lime is often used as a PH buffer in soil.

Also, I don't mix nutes or do anything until I'm ready to use it. WIth PH that high and that much of a swing, you may want to consider using RO water, which will be a bit more stable for you. Wal-Mart's "Drinking Water" (not distilled) is R/O, and only like $0.68.

Give that a try, see if your PH stabilizes.

Thanks alot for the answer but i have to say im not 100% sure what you mean (I dont have english as first language and im not from us ^_^)
What is "RO water"? Rain water?
Im using a bottle that looks like this (took the photo 2 secs ago)

So what you suggest is that i use the ph- right before i water my plants to get it to the level they like?, ones its in the earth it probaly more stable becouse the earth it self has a ph around 6-6.5.
Am I correct?

 

[dvine]

Here are some previous atempts of growing (same problem). The difference here is that i had another soil (more powerfull) and did not add any ph- solutions.

 

[NiteTiger]

Looks like PH induced lockout to me. R/O water is Reverse Osmosis, a purifiying method that removes almost all contaminants, which gives you a nice stable base to work from when mixing nut solution.

 

[dvine]

I live in a contry where buying water is RARE, we have so good normal tapwater so we basicly never drink water from bottles so therefor all water we can buy are realy expencive. Is there some way i can make my tapwater be more stable or do i simply just have to adjust it right before i water with it?


Btw, soon there will be winter, how good are melted snow to use?
What about lakewater/riverwater???