Light question for seedlings.

Cornishi

Cornishi

Well-Known Member
So I've found I'm running into issues everytime I'm starting my seedlings off.

A friend of mine starts his the exact same way but gets different results to me.

Both of us run a 600watt HPS, same 20/4 cycle and just plain water till they get going.

The differences are:
His sprout and grow as you'd expect, exponential growth day after day. Strong green foliage.
Mine are stunted after the first set of leaves, they don't seem to like my light at all. Leaves immediately start to fade and yellow.

I whacked mine under a T5 and within a day they're going solid green and the growth is kicking in.

What can cause such disparity between lights? It doesn't make sense to me.

I get that HPS lighting can be too strong for seedlings, but that doesn't explain the different results.
 
hotrodharley

hotrodharley

Well-Known Member
Cornishi said:
So I've found I'm running into issues everytime I'm starting my seedlings off.

A friend of mine starts his the exact same way but gets different results to me.

Both of us run a 600watt HPS, same 20/4 cycle and just plain water till they get going.

The differences are:
His sprout and grow as you'd expect, exponential growth day after day. Strong green foliage.
Mine are stunted after the first set of leaves, they don't seem to like my light at all. Leaves immediately start to fade and yellow.

I whacked mine under a T5 and within a day they're going solid green and the growth is kicking in.

What can cause such disparity between lights? It doesn't make sense to me.

I get that HPS lighting can be too strong for seedlings, but that doesn't explain the different results.
Click to expand...
Distance from the light?
 
A

AlaskanAutoGrower420

Well-Known Member
Hps is never a good idea for seedlings, you want to be using a mh bulb for veg all the time, hps causes stretched node spacing, and with the seedlings it just causes them to stress out, are you using it at 50% on the ballast? 100% is way overkill for them little seedlings.
 
Cornishi

Cornishi

Well-Known Member
Didn't wanna get into mediums and stuff too much. Just wondered if there is potential for differences between HPS bulbs etc?
Mine is a digital ballast and my mates is a straight up 600 watt.
I don't mess with mine as i'm starting fresh seedlings whilst I'm finishing my cheeses off in the same grow space.
I've rigged my T5 system in the same space now so it's no biggy.

Just wanted to figure out how it can work for one person and not for another.

I grow in coco coir 60/40% perlite. He grows is basic peat/soil from garden store.
Light is a good 3ft away from them.

I think I'll just stick to starting seedlings under T5 from now on until they are a foot tall or summit.
 
the chin

the chin

Well-Known Member
I do all seeds an veg under 600 hps... I hav a shelf build behind the light and can get the seedlings up very close to the bulb so they don't stretch and grow vigorously..... But I can't veg directly under the hps either without bein to far away causing bad growth an stretch or two close an burning them up
 
hotrodharley

hotrodharley

Well-Known Member
Just keep them at a distance if you do at 4 days. I put all seedlings under MH as soon as I transplant them into red cups but that's at about 1 week after they pop.
 
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bird mcbride

bird mcbride

Well-Known Member
Cornishi said:
So I've found I'm running into issues everytime I'm starting my seedlings off.

A friend of mine starts his the exact same way but gets different results to me.

Both of us run a 600watt HPS, same 20/4 cycle and just plain water till they get going.

The differences are:
His sprout and grow as you'd expect, exponential growth day after day. Strong green foliage.
Mine are stunted after the first set of leaves, they don't seem to like my light at all. Leaves immediately start to fade and yellow.

I whacked mine under a T5 and within a day they're going solid green and the growth is kicking in.

What can cause such disparity between lights? It doesn't make sense to me.

I get that HPS lighting can be too strong for seedlings, but that doesn't explain the different results.
Click to expand...
You were probably not watering the seedlings enough for the HID. That's why they're doing better under the t5's.

I recommend for the serious grower a 1kw hps 12/12 set at approx 44" from glass to medium for seedlings and no veg time.
 
bird mcbride

bird mcbride

Well-Known Member
First off, 12/12 is for regular seeds and we're in the auto section.

To satisfy and not jump the thread I'll say that auto's don't/can't veg and the permanant light schedule is 20L/4d.
 
Last edited by a moderator:
B

brimck325

Well-Known Member
Cornishi said:
So I've found I'm running into issues everytime I'm starting my seedlings off.

A friend of mine starts his the exact same way but gets different results to me.

Both of us run a 600watt HPS, same 20/4 cycle and just plain water till they get going.

The differences are:
His sprout and grow as you'd expect, exponential growth day after day. Strong green foliage.
Mine are stunted after the first set of leaves, they don't seem to like my light at all. Leaves immediately start to fade and yellow.

I whacked mine under a T5 and within a day they're going solid green and the growth is kicking in.

What can cause such disparity between lights? It doesn't make sense to me.

I get that HPS lighting can be too strong for seedlings, but that doesn't explain the different results.
Click to expand...
what was your humidity under the 600 vs. the t-5?
 
bird mcbride

bird mcbride

Well-Known Member
When I put clones/seedlings under the HID I cut a 5-6" square piece of reflective plastic with a slit to the middle and an appropriate size hole in the center of the plastic and is placed at the base of the clone/seedling ASAP. This not only helps to keep the area around the base of the new plant moist until it can gain a larger root mass but it also helps to keep the light from getting through to the roots.
 
Last edited by a moderator:
Cornishi

Cornishi

Well-Known Member
bird mcbride said:
When I put clones/seedlings under the HID I cut a 5-6" square piece of reflective plastic with a slit to the middle and an appropriate size hole in the center of the plastic and is placed at the base of the clone/seedling ASAP. This not only helps to keep the area around the base of the new plant moist until it can gain a larger root mass but it also helps to keep the light from getting through to the roots.
Click to expand...
That sounds like a fair idea.
May give that a go next time round. Although I am wanting to give DWC a bash. Gotta figure out water temps for that though. Different ball game eh!
 
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