how many grows?

[stonescafe]

need to ask this question as im not sure! how many grows can a 400 watt hps lamp grow before it needs to be replaced,so far it has grown 4 crops, and when i replace it im thinking of upgrading it to a 600, will this give me slight improvement on yields etc etc.any help on this subject is greatly apprecaited.

 

[drelow31@yahoo.]

ya that improvment wood probally more than double your yeild cause u have twice the lumens

 

[BL4ZE20]

I'd say it's about time to replace the bulb. but if your upgrading to a 600watt then theres no need in replacing the bulb since you'll have a new setup anyways.
unless you plan on using the 400 also then i'd go ahead and replace it.

 

[FreezerBoy]

"4 crops" is devoid of meaningful information. Do you mean less than 8 months, more than 2 years or somewhere in between? How many hours has it burned? How many hours is it rated for? You don't want to run it all the way to the end but, I'd keep it to at least the 66%-75% range.

 

[Azeotrope]

I would not expect twice the yield from a 600w upgrade. Lumens are like fools gold. They are not worth anything when talking about plant growth. Don't listen to fools that talk about them. I did have a good chuckle at that reply though.

A 600w bulb will raise your temps quite a bit if you are not equiped for it.

FreezerBoy is correct. Does that mean veg + flower? What you need to evaluate the number of hours burned.

 

[Quazi]

People preaching that lumens are "useless" don't understand what they are or how they are measured.

And don't you dare come back here telling me what PAR is... I already know.

-Q

 

[FreezerBoy]

Quaz, I luvs ya (no, I don't want your beer :friends but, I'm with Az on this one. P'tooey on lumens.

 

[messn'n'gommin']

need to ask this question as im not sure! how many grows can a 400 watt hps lamp grow before it needs to be replaced,so far it has grown 4 crops, and when i replace it im thinking of upgrading it to a 600, will this give me slight improvement on yields etc etc.any help on this subject is greatly apprecaited.

Please, do not misunderstand, I am not trying to be a smart-a$$, but your question is a bit too open ended. It is like asking that since you have been to four major cities, is it time to buy another car and would you see better gas mileage if you do?

HID bulb life is rated by the hours used and, to a lesser extent, the consecutive hours it burns also plays a factor (the more the bulb cycles on and off for less time per cycle reduces the rated life somewhat). Most HPS bulbs (there are exceptions and I have never used MH) are rated for 20,000 hours. A 12/12, 60 day schedule equates to 720 hours (an 18/6, 30 day schedule means an additional 540 hours) of life used per crop "cycle." Or almost 28, 12/12, 60 day cycles before failure.

However, plants "see" light a bit differently than human beings and what they "see" is rated in PAR (Photosynthetically Available/Active Radiation). PAR can be graphed as a lop-sided "M" with peaks in the blue and red (a bit more red than blue), and stretching well into UVB (starting at about 280nm) and well into FR (Far-Red, starting at about 700nm) wavelengths. The human eye see's light from about 380-400nm's to about 680-700nm's with a single peak right in the middle that we see as "white" light. That is why most who understand the basics of light and its relationship to photosynthesis, more or less, reject the measure of light in lumens to rate a particular bulb.

Taking into consideration that bulb manufacturers make most of their products for the human eye, that is why bulbs are rated in lumens and is what most people are used to. Lumens serve as a relative, but an inexact and unreliable, measure of light for a growers purposes.

Lumen maintenance means that a particular bulb will maintain a minimum of intensity after a sharp decline after about 3000-5000 hours of use (bulb and even manufacturer specific) to a gradual decline of a less intense level to about 70-80% of its rated lumens before failure. That is why commercial growers change their bulbs after a few grows (and I have seen a couple who said they change then every run). The initial loss of lumens equates to a reduction in yield, but, at least to me, is less of a factor for a small, personal use grow.

One of the best tutorials in lay terms on light and photosynthesis, can be found at a reef keeping site. If you like you can find them them (a four part series) here:

From "Reefkeeping," an online magazine

http://reefkeeping.com/issues/2006-02/sj/index.php
Part I: “What is Light?,”
http://reefkeeping.com/issues/2006-03/sj/index.php
Part II: “Photons,”
http://reefkeeping.com/issues/2006-04/sj/index.php
Part III: “Making Sense of Light Measures,”
http://reefkeeping.com/issues/2006-05/sj/index.php
Part IV: “Color Temperature,”

It is my suggestion that anyone and everyone copy them to file and read, read, read at their leisure.

So...lol...after all that. Yes, upgrading from 400w to 600w is a good move, provided heat management is dealt with properly.

Hope this helps some.

Namaste, mess

 

[Quazi]

*sigh* I'm so tired of repeating myself.

I'm writing a thread now just to put this whole "lumens are useless" business to rest once and for all.

I'll throw the link here as soon as I'm done.

EDIT: The Truth About PAR, Lumens, and Plants (May Surprise You)

-Q

 

[stonescafe]

yes this does include veg and flower so i estimate that the bulb has been used for around 6,500 hours so thanks to messn n gommin ive decied to replace the bulb!thanks for your help folks.

 

[Moppel]

are you from the stonescafe/coffeeshop in amsterdam?

 

[happyherb]

i run'em till they die....then put a new one in and ive seen the same yeild pretty much..also many times from a second hand shop bought 2nd hand ones....so dont loose sleep over it...HH. =]-~

 

[CMoon]

need to ask this question as im not sure! how many grows can a 400 watt hps lamp grow before it needs to be replaced,so far it has grown 4 crops, and when i replace it im thinking of upgrading it to a 600, will this give me slight improvement on yields etc etc.any help on this subject is greatly apprecaited.

id say 4 grows is about max includeing vegging

 

[swampdank]

i would replece it. nip it in the bulb.