changing from HPS to MH. will this create problems?

honda5150

honda5150

Active Member
Ok , i have 2 1000 watt HPS hydro farm lights. I have 17 female clones 4 days old and keep them outside all day in the sun, then bring them in under ONLY 1 1000 watt HPS light about 4 feet from the plant. I was going to just use the HPS but hear that MH is much better for the veg stage. So, my question is, is it too late to switch them to MH now? I will still keep them outside for day sun, but during the night keep them under the MH light. My goal is to get them as big as possible under the MH until they are about 2 feet then switch to HPS. anyhelp would be great. thanks. ALSO, i can only afford 1 bulb, so can i have 16 babies under 1 1000 watt light, with a MH bulb too? Then once ready for flowering use both of the 1000 watts HPS bulbs? please let me know if this sounds like a solid plan. Most important questions or concern is,is it too late to switch to MH since i have been running the HPS for the last 4 days ( currently have the lights 4 feet away from the babies so i dont burn them.
 
Caregivin

Caregivin

Well-Known Member
HPS will stretch the plants, it is fine for veg. MH will make the plants grow more compact. You will see it if you veg in mh then flower in hps the plants will stretch quite bit after the change in light. Light stress can make your girls go tarded or grow male tendencies, be careful when playing with light cycle more so than source, meaning the amount of time and light it recieves is most important.IMO. If you are still in veg cycle you will be fine. once you flower for 2 weeks it is tough to go back!
 
honda5150

honda5150

Active Member
ok, maybe i didnt explain correctly. Theswe are all clones that have been in light for only 4 days, so we are very far from going into the flowering stage. 12 on 12 off. I am doing 24 hours of light as stated above, then vegging them under 1 1000 watt light about 4 feet above the plants. My question is will it be an issue if i go to 100 watt MH buld instead of the HPS i have in now. THEN ofcourse i will use the HPS for the flowering stage in a few weeks. I understand about changing the light cycle later in the process can be harmful. thank you for the feedback, but still wondering what would create more yield, and more importantly, can i switch to MH NOW?



Caregivin said:
HPS will stretch the plants, it is fine for veg. MH will make the plants grow more compact. You will see it if you veg in mh then flower in hps the plants will stretch quite bit after the change in light. Light stress can make your girls go tarded or grow male tendencies, be careful when playing with light cycle more so than source, meaning the amount of time and light it recieves is most important.IMO. If you are still in veg cycle you will be fine. once you flower for 2 weeks it is tough to go back!
Click to expand...
 
M

miteubhi?

Active Member
The thing that will stress them the most is going outside to in every day.
If I were you I'd keep 'em in all d time.
The change in bulbs should not harm them though.
Four feet is kinda far, even for hardening off.
 
danno48

danno48

Active Member
Changing from HPS to MH or v/v during vegging is no problem. However, MH for vegging, then HPS for flowering is ideal. You're gonna need more than a 100w MH bulb though. 100W HID lights might be good for one, possibly two plants is all. You can (and should) put your light a whole lot closer to those little ones than 4 feet. I would say 18-24 inches. Putting even 1000w that far away (4 feet) is gonna cause major stretching whether MH or HPS. IMHO a fat little bushy plant is a very happy plant. It's a lot easier to stretch out a short bushy plant than it is to make a tall, spindly plant fill out. If you're putting them outside to save electricity, you should realize that you are causing more stress by taking them in out like that and you ain't saving much electricity at all. Although I think 24/0 is great for vegging, 18/6 does save electricity and some say that it is even better for the plant. Keep 'em inside at around 100w HID per plant and 18-24 inches from the tops and you and they will be happy campers.
 
M

mad season

Member
can i keep my 400w hps in under 30 cm ass long as the temperature is under control due to air-condetion? thanks for the help!!!
 
honda5150

honda5150

Active Member
ok cool, thank you. I was told that its good to take them out everyday, but i actually hate it because its work, and am fine about the electricity bill. I will keep them inside from now on then. So, 4 feet is too far, even though i have a 1000 watt HPS on them? I will move them down to 2 feet and see how it works out, thanks. It was a mis-type above where i mentioned 100 watt, meant i wanted to switch to a MH light because i heard that is ideal. I just to be able to buy a bulb for vegging that will fit into my 1000 watt hood & light so i dont have to get a whole new set up for the veg. state, then i can just put my HPS bulbs back in once im ready to flower. One thing, what do you mean by "Keep 'em inside at around 100w HID per plant"? sorry, first time grower.


danno48 said:
Changing from HPS to MH or v/v during vegging is no problem. However, MH for vegging, then HPS for flowering is ideal. You're gonna need more than a 100w MH bulb though. 100W HID lights might be good for one, possibly two plants is all. You can (and should) put your light a whole lot closer to those little ones than 4 feet. I would say 18-24 inches. Putting even 1000w that far away (4 feet) is gonna cause major stretching whether MH or HPS. IMHO a fat little bushy plant is a very happy plant. It's a lot easier to stretch out a short bushy plant than it is to make a tall, spindly plant fill out. If you're putting them outside to save electricity, you should realize that you are causing more stress by taking them in out like that and you ain't saving much electricity at all. Although I think 24/0 is great for vegging, 18/6 does save electricity and some say that it is even better for the plant. Keep 'em inside at around 100w HID per plant and 18-24 inches from the tops and you and they will be happy campers.
Click to expand...
 
honda5150

honda5150

Active Member
ok cool, i was just worried about burning the plants since they are so small, and it being a 1000 HPS light on them. no worries then? cool. thanks.


miteubhi? said:
The thing that will stress them the most is going outside to in every day.
If I were you I'd keep 'em in all d time.
The change in bulbs should not harm them though.
Four feet is kinda far, even for hardening off.
Click to expand...
 
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