T5's need help!

Kingrow1

Kingrow1

Well-Known Member
So a few months ago i upgraded to some t5 flouros from some t8's i had. Seemed like a good investment as T5's are much brighter and they came in one solid unit. I have had plenty of experience with flouros over the years and run the regular and HO T5's before but never 4 together in my veg room.

Now it seems misleading when people say you can get seedlings up to 2inches from the lights? I seen people flower and harvest good yeilds under these let alone need a seedling that close.

Armed with this crazy information i have tried to sprout seedlings and keep tham close to the lights but even at 6inches i have heat problems. Seems that the optimun distance for seedlings under T5's with decent ventilation is nearer 12inches than 2inches.

Anyone else find that seedlings perform poorly under T5's when not 12 inches away? By the way these are the HO/High Output T5's not just standard ones. Peace
 
Kingrow1

Kingrow1

Well-Known Member
Yer its mainly the seedlings that have problems, more than 6 inches close and heat stress, bigger plants can get quite close no problems even touch them but seedlings im close to 12 inches away or problems. I got a big fan blowing in between lights and plants. Peace

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Total Head

Total Head

Well-Known Member
Kingrow1 said:
Yer its mainly the seedlings that have problems, more than 6 inches close and heat stress, bigger plants can get quite close no problems even touch them but seedlings im close to 12 inches away or problems. I got a big fan blowing in between lights and plants. Peace

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i've been vegging with t5 for a couple years. when you say "heat problems" what do you mean? i can't tell from the pic what is wrong with the seedling aside from being a bit stretched. i would definately have both those plants closer to the light, but i'm curious as to what you mean when you say heat problems. the only problems i have with my t5 is when i don't check the plants for a day and they grow into the light a bit because i have the light so close. i start them about 8 inches from the light (from seed) and when they start to grow into the light i start lst, and from that point on they are within a few inches at most. once a clone roots i usually start it about 4 inches away. i have a fan blowing and a fan sucking (cheap table fans, less than 40w each) and the light is inside a closed (not airtight) tent. i've never had a problem unless the actual temp in the room itself gets too hot.
 
Kingrow1

Kingrow1

Well-Known Member
Total Head said:
I start them about 8 inches from the light (from seed) and when they start to grow into the light i start lst, and from that point on they are within a few inches at most. once a clone roots i usually start it about 4 inches away. i have a fan blowing and a fan sucking (cheap table fans, less than 40w each) and the light is inside a closed (not airtight) tent. i've never had a problem unless the actual temp in the room itself gets too hot.
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The picture was just of my veg box to show the setup.

That was my problem as i was starting seedlings way to close compared to your eight inches and then they were just growing up problematic so to say. I went and moved my light up after looking at various grows with them as i realised those things kick out some light and heat.

Thanks for saying the distance you place your seedlings, im almost postitive this was the mistake i was making. When i say heat problems i would associate that with placing seedlings only 4 inches under the light, not necessarialy heat but more light etc etc maybe humidity.

Surely too close and just wanted to check distances with other T5 growers. Peace
 
ohmy

ohmy

Well-Known Member
I am using t8's when out of dome and light is right on top of em. 1/2 inch or so away with My fan set up so it's blowing straight under the light making the seedling sway real good. My t5's is set them so they are just about to tuch the dome with the fan blowing straight accross to keep temps down a lil.. If you could raise your plant bed a lil so the fan is blowing straight accros it might help rather then having the fan blowing down
 
Kingrow1

Kingrow1

Well-Known Member
ohmy said:
I am using t8's when out of dome and light is right on top of em. 1/2 inch or so away with My fan set up so it's blowing straight under the light making the seedling sway real good. My t5's is set them so they are just about to tuch the dome with the fan blowing straight accross to keep temps down a lil.. If you could raise your plant bed a lil so the fan is blowing straight accros it might help rather then having the fan blowing down
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My fan is set in optimal position so it blows over all plants, inbetween the lights and gives greatest exhaust out of my cupboard door.

My T5's are high out put ones with ballasts and i couldnt get seedlings very close without problems even with decent temps, strange i know but i read a lot of other threads where growers had the same problems with seedlings and very young plants, TotalHead above sums it up at 8 inches, seems about the closest my seedlings wana be, even turn away from the light sometimes when there closer.

I use to run T8's then a mix of T8's and T5's but now just T5's and they seem twice the strength of my T8's pretty much. Seedlings for T8's could go at 4 inches but T5's seem twice the distance and 100watts of T5's means um just gona start seedlings at 12 inches and work them up into the light. Bigger plants have no problem getting closer but still 6inches seems an optimun distance for them. Peace
 
ganjames

ganjames

Well-Known Member
seems like a complicated problem, you have the one growing plant which will want all of the t5 bulbs on to get good growth. and then you have the seedling which is stretching becuase it's too far from your t5 lights, but you can't get it closer because all of the lights are on for the bigger plant which it causing too much heat for the seedling. this is why i always start all of my seeds at once, my fixture has a switch to turn on all of the bulbs, the bulbs on the far ends or just the two bulbs in the middle. so i can just flip on the middle two bulbs for the seedlings, keep the bulbs about 4-6 inches away, and then after a couple weeks when growth starts to take off i can go ahead and raise the lights and flip on all of the bulbs.
 
Kingrow1

Kingrow1

Well-Known Member
ganjames said:
seems like a complicated problem, you have the one growing plant which will want all of the t5 bulbs on to get good growth. and then you have the seedling which is stretching becuase it's too far from your t5 lights, but you can't get it closer because all of the lights are on for the bigger plant which it causing too much heat for the seedling. this is why i always start all of my seeds at once, my fixture has a switch to turn on all of the bulbs, the bulbs on the far ends or just the two bulbs in the middle. so i can just flip on the middle two bulbs for the seedlings, keep the bulbs about 4-6 inches away, and then after a couple weeks when growth starts to take off i can go ahead and raise the lights and flip on all of the bulbs.
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There is always 5-6 plants in it just took some out for the pic which is from a few weeks ago anyway. I can adjust the height of the seedlings and the unit is always full on or nothing basically.

I think the problem is that at 96watts for under 2 foot squared leaves me over 50watts a square foot and more than enough for seedlings hence why i have to keep them 8inches away for the first week i guess.

Not really that complicated just getting use to T5's and seedling distances i suppose. Peace
 
ganjames

ganjames

Well-Known Member
can you cut a hole in your box and install a fan to vent all of the air out? that would bring the temp of the box down at least 10 degrees, then you can raise the seedling.
 
Kingrow1

Kingrow1

Well-Known Member
ganjames said:
can you cut a hole in your box and install a fan to vent all of the air out? that would bring the temp of the box down at least 10 degrees, then you can raise the seedling.
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It never goes over 25degrees celcius and bigger plants are ok, its just the seedlings but think i got it sorted moving the light futher away. The fan blows the air from the lights out of the door and the doors are always open or ajar. Peace
 
ganjames

ganjames

Well-Known Member
Kingrow1 said:
It never goes over 25degrees celcius and bigger plants are ok, its just the seedlings but think i got it sorted moving the light futher away. The fan blows the air from the lights out of the door and the doors are always open or ajar. Peace
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hmm then i don't know how it can be a heat problem, i've had seedlings hit 30-33 celcius and be fine.
 
Kingrow1

Kingrow1

Well-Known Member
ganjames said:
hmm then i don't know how it can be a heat problem, i've had seedlings hit 30-33 celcius and be fine.
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I know its been troubling me too, all i can think is we had a bit of a heat wave a week ago and seedlings just havent recovered from this, i have one just germinated two days ago that i have placed at about 10inches so will se how that dose and will move up towards the light again to find the optimun distance. Peace
 
bonjo78

bonjo78

Active Member
u upgraded the lights , now u need to upg the vent too , box + t5 tough combination , a little hps with cool tube does the job better imo

use wider than taller pots
 
Kingrow1

Kingrow1

Well-Known Member
bonjo78 said:
u upgraded the lights , now u need to upg the vent too , box + t5 tough combination , a little hps with cool tube does the job better imo

use wider than taller pots
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I did, a pc fan use to be able to do it with my T8's so got that big fan at the back for the T5's. Just wanted to hear what the general distances people started their seedlings at under HO/T5's. Peace
 
Kingrow1

Kingrow1

Well-Known Member
bonjo78 said:
its the circulation that its been raised the vent tho remained the same
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Nope, everythings cool just checked before and at 12 inches away they growing very fast and happy. Simply just had them too close to the lights. Forgot how strong those High Output T5's with independant ballasts are. Can flower with them you know so are too strong to get seedlings too close. Seedlings look real good now but thinking of maybe going back to my T8's as the T5's are a little bit overkill for a small veg area, feel like i should be flowering autos under em not seedlings and small veg plants. Really do give Hps a run for their money i reckon. Peace
 
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