# CMH bulb replacement **URL:** \ **Category:** Lighting\ **Created:** [August 28, 2021, 5:00pm UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996 "2021-08-28T17:00:22Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![rotty508](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/rotty508/32/562579_2.png) [@rotty508](https://ilgmforum.com/u/rotty508)\ **Post date:** [August 28, 2021, 5:00pm UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/1 "2021-08-28T17:00:22Z")
Bumping up my grow a little this time around. I currently have Growers choice dual 315W CMH with just their bulbs it came with (3K-R) red enhanced. Have only done 2 grows with these so far. I’ve read where some people use different bulbs for veg & flower. Wondering on thoughts about doing that? I have to buy an extra bulb just incase one blows so If i am going to buy new bulbs i want to get what’s best. I also added a Spiderfarmer SF4000 so i will be running both lights for 10 plants covering 4x8. Thanks for the help. ---
**Author:** ![MidwestGuy](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/midwestguy/32/914277_2.png) [@MidwestGuy](https://ilgmforum.com/u/MidwestGuy)\ **Post date:** [August 28, 2021, 5:15pm UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/2 "2021-08-28T17:15:15Z")
> [@rotty508](#): > > different bulbs for veg & flower CMH for veg and HPS for flower is what some people will do. ---
**Author:** ![rotty508](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/rotty508/32/562579_2.png) [@rotty508](https://ilgmforum.com/u/rotty508)\ **Post date:** [August 28, 2021, 5:16pm UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/3 "2021-08-28T17:16:55Z")
ohh i thought it was just a different wavelength. I will have to check if my light can do both. I wouldn’t think so. Just looked all the HPS are screw in so im not buying a 3rd light. I’ll just stick with what i got and buy an extra bulb. Thank you ---
**Author:** ![MidwestGuy](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/midwestguy/32/914277_2.png) [@MidwestGuy](https://ilgmforum.com/u/MidwestGuy)\ **Post date:** [August 28, 2021, 5:24pm UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/4 "2021-08-28T17:24:04Z")
Don’t quote me on this as I’ve never used bulbs, but I believe that CMH and HPS are interchangeable in the same fixture. @dbrn32, true? ---
**Author:** ![Allinherhead](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/allinherhead/32/525479_2.png) [@Allinherhead](https://ilgmforum.com/u/Allinherhead)\ **Post date:** [August 29, 2021, 4:14am UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/5 "2021-08-29T04:14:27Z")
Doesn’t change work for veg and flower without changing… ---
**Author:** ![NeoGroR](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/neogror/32/545754_2.png) [@NeoGroR](https://ilgmforum.com/u/NeoGroR)\ **Post date:** [August 29, 2021, 4:55am UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/6 "2021-08-29T04:55:30Z")
I’m pretty sure you can’t. Just because there is 315w HPS bulb. ---
**Author:** ![NeoGroR](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/neogror/32/545754_2.png) [@NeoGroR](https://ilgmforum.com/u/NeoGroR)\ **Post date:** [August 29, 2021, 5:49am UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/7 "2021-08-29T05:49:00Z")
I’ve listened to a few podcasts that say 4100k CMH bulbs can grow KILLER weed. Super terpy and great for extractions. I don’t grow under a CMH, but if I did it would be a 4100k Cultilux bulb or a Hortilux CMH bulb. I don’t think I can post YouTube links on here but look up this episode of Growcast for more information on CMH. ![image](https://global.discourse-cdn.com/growingmarijuana/original/4X/0/a/6/0a63b9e7fa990c87815819ad8259eee55f03fb62.jpeg) ---
**Author:** ![dbrn32](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/dbrn32/32/533801_2.png) [@dbrn32](https://ilgmforum.com/u/dbrn32)\ **Post date:** [August 29, 2021, 3:07pm UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/8 "2021-08-29T15:07:44Z")
Negative. At least I have never seen ballast compatible with both. Most digital ballasts will run both metal halide and high pressure sodium, but ceramic metal halide requires its own. ---
**Author:** ![GrizzlyGrows](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/grizzlygrows/32/1097976_2.png) [@GrizzlyGrows](https://ilgmforum.com/u/GrizzlyGrows)\ **Post date:** [August 29, 2021, 4:17pm UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/9 "2021-08-29T16:17:23Z")
Cmh is definitely different. Different wattage bulbs and the ballast puts out different wattage. Mh and hps won’t work on a cmh and vice versa ---
**Author:** ![rotty508](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/rotty508/32/562579_2.png) [@rotty508](https://ilgmforum.com/u/rotty508)\ **Post date:** [August 29, 2021, 9:45pm UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/10 "2021-08-29T21:45:17Z")
Is these a good place you guys like to get bulbs at or just a google search? I’ve found recently best price isn’t always the best place to go. So now i try and ask for recommendations on pricey items. Thanks again for the help. ---
**Author:** ![NeoGroR](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/neogror/32/545754_2.png) [@NeoGroR](https://ilgmforum.com/u/NeoGroR)\ **Post date:** [September 21, 2021, 2:22pm UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/11 "2021-09-21T14:22:09Z")
I’m surprised no one has responded to this! So sorry for the delay. Go to Cultilux dot com. Contact them via email or by phone to place an order. (A pain in the butt but worth it) Mention you heard them on Growcast and you’ll get 10% off ---
**Author:** ![Pet\_de\_Chien](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/pet_de_chien/32/565754_2.png) [@Pet\_de\_Chien](https://ilgmforum.com/u/Pet_de_Chien)\ **Post date:** [September 21, 2021, 3:42pm UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/12 "2021-09-21T15:42:56Z")
Yes, ONLY if you have a switchable ballast, I have a few old dogs in storage, that you have to toggle the HPS/MH switch. ---
**Author:** ![rotty508](https://sea2.discourse-cdn.com/growingmarijuana/user_avatar/ilgmforum.com/rotty508/32/562579_2.png) [@rotty508](https://ilgmforum.com/u/rotty508)\ **Post date:** [September 21, 2021, 4:44pm UTC](https://ilgmforum.com/t/cmh-bulb-replacement/73996/13 "2021-09-21T16:44:17Z")
Thank you