When is it ok to switch young plants over to a high intensity light?

[reality]

The title is my question. The little plants I have have two pairs of serrated leaves not including the 2 starter leaves.

 

[highman]

was just wondering the same thing.. mine are about 2 inches 2.5 under 2 2 footers with mixed 5000k and 6500k bulbs. Today i took the dome off for maybe 3 hours and when i came back a couple of them were withering. This may have been from the old b1 i added the night before so when i watered today i used just ph adjusted water. I stuck them outside for some of that good ole natural sunlight and put the dome back on so my rockwool will stay damp. my outside temps are around 87-90 so im a bit worried the temps will be to hot. I had an idea using a cheap white common house hold air filter hanging directly above my dome inorder to dial down some of the intensity.

 

[highman]

my question is more directed towards direct sunlight under a dome but it is the same concept i quess

 

[reality]

are these clones or seedlings? can you see the roots coming thru whatever kind of medium u r using? If so I would recommend taking off the dome. You dont want 100 % humidity and thats what the dome tends to keep. You want it to be somewhat dryer to encourage the roots to seek out water and get bigger.

Can anyone answer my simple question?
I cant find an answer in my searches

-Reality

 

[StoneyBud]

The title is my question. The little plants I have have two pairs of serrated leaves not including the 2 starter leaves.

The best answer to your question is to explain how much light your plants need at *any* given time.

5,000 lumens per/square foot of plant canopy.

or

34.72 lumens per/square inch of plant canopy.

It's that easy.

Move your tiny plants together until their leaves are almost touching, and then, in your mind, draw a box around them so that the box touches the outermost edges of the leaves.

This is your canopy area.

If you then measure that box on one side and on either the top or bottom, multiply the two numbers, you now have the square area of your plant canopy.

Let's say it's three inches on the side and two inches on the top.

That's three times two = 6 square inches of canopy area.

34.72 times 6 = 208.32 lumens needed for your little plants.

You'll notice that amount is really small. It would be difficult to buy a light that only provided that amount of lumens.

So what you do is raise a small light with MORE lumens until it provides NEAR that amount.

It's all simple math my friend. Look on the package that lights come in and you'll see, somewhere on that package, the amount of LUMENS that the light produces.

"Lumens" are an international standard of rating based on the amount of light that will strike a globe at exactly one foot from the source of light.

Each time you double the amount of distance, the amount of lumens should decrease by approximately half.

Tiny little seedlings need only a very small amount of light. A 24 watt CFL placed at about 4 inches above your seedlings will give it all the light they can use.

When you start noticing your seedling "stretching", it's time to transplant it into a larger container and bury it up to it's starter leaves in lightly tamped soil and increase your light slightly.

All lights produce IR light. The larger the light, the more IR it produces.

Too much IR and your plant gets fried.

IR is not affected by wind. Fans won't decrease the amount of IR hitting your plants.

IR does decrease nicely with distance. The secret is to get enough usable light at a distance that reduces the IR to a non-frying amount.

I hope this post hasn't overwhelmed you with information.

Re-read it a few times and think about what I've said. It'll make sense to you.

Good luck to you !

 

[CoolAsAFan]

just start them further away from your HID and gradually close the distance as they "harden"

 

[highman]

decided to use the air filter methode well see how it works

 

[reality]

Okay...I havent grown from seed in a while and I remember reading something about HIDs burning up seedlings. I only have 2 to 2 and half feet of clearance between my plants and a 400W.

 

[CoolAsAFan]

if your temps are ok, you should be fine. just check on them often during the first few days. what lights are they currently under?

 

[highman]

are these clones or seedlings? can you see the roots coming thru whatever kind of medium u r using? If so I would recommend taking off the dome. You dont want 100 % humidity and thats what the dome tends to keep. You want it to be somewhat dryer to encourage the roots to seek out water and get bigger.

Can anyone answer my simple question?
I cant find an answer in my searches

-Reality

seedlings, my experience with seeds in very minimal as well i have removed the dome and they look good im going to keep them open while outdoors and back in the dome when they come back inside.

 

[reality]

Ive got em under one of those Sunleaves t5 with four tubes but its much father away than i usually keep it because I broke my light mover.

 

[CoolAsAFan]

imo, id go ahead and stick them under your MH and just watch closefully the first couple of days. happy growing

 

[dowjones618]

Nicely done!