how often to change bulbs

[RuralRoute420]

hps - how often should they be changed. after looking at it for a year, can't really tell a difference... i guess only half a year, being on 12/12.

 

[Opus]

what wattage? a 400 hps has 1/2 the life of a thousand hps... I change my bud room bulbs (the 12 on-12 off) every 4 months... the 2- 400 watt MH bulbs in my veg area get changed aprox every 3 months.

I have a pretty good light meter I found at a sally-anne thrift store for a dollar and that also helps me when I check my bulbs.

 

[Verite]

Most hps are rated for 20,000 hours. A month of 12/12 is 360 hours.

 

[RuralRoute420]

sorry, it's a 250...

 

[NAACP]

I have read that a 1000watt HPS bulb has a life of about 20,000 hours, but after about 5000 hours though 208 days of 24hrs on they lose about 25%-35% of there light intensity. I run 3 1000 watt HPS so what I do is I replace the bulbs when I switch to 12/12 and the next cycle of 18/6 I keep the bulbs then I replace them when I start flowering again.

 

[Guest]

I change my 400w hps bulbs every 8-10 months, always on 12/12

 

[Guest]

I change all my bulbs, HPS, MH, and fluros, every 4 months. If I leave it any longer yields start to deminish.

 

[Closet Funk]

I say change them every few grows. If your growing perpetual style then maybe every other grow. If using smaller HPS lights then I would change them pretty often. The small HPS lights are weak as it is and a tore down bulb will make it weaker.