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Seedlings in light


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Hey guys,

 

This is my first attempt at growing. I have a 1x1m hydro grow tent with 4 seedling currently under a 400w MH light. They've been under the light for about a week but haven't really change since. They are in rockwool which I have now planted into coco coir. They are currently on a 16/8 light cycle. The fan is also only running when the lights are on.

I have attached some pics.

 

Is it too early to start add nutes to these seedlings? At what point should I add nutes?

 

I read I should wait until I see first real leaves but what does that mean?

 

Any help will be appreciated.

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Hey Newbud,

First off, Welcome to OS.

Placing freshly cracked seedlings under HID (High Intensity Discharge) ie MH or HPS lighting is a bit of overkill. Babies need to be nurtured, not beaten into submission lol

I start mine under a fluro light in a rockwool cube sitting in an esky. They stay under the fluro until the roots are covering the base of the 4inch x 4inch cube, then I transfer to pots.

 

By the statement "...wait until I see first real leaves..." it means the first serrated leaves. The first leaves that appear are smooth oval shaped, they are called cotyledon. These are the plants embryonic leaf. They contain nutrients for the seedling to establish itself. The next pair of leaves are the first serrated set. When the 2nd set of serrated leaves are fully formed I start adding nutrient at around 500-600ppm or a bit less than 1/2 strength Personally I like to have 2, often 3 pairs of serrated leaves present before planting. By the time I have 3pairs fully formed the nutrients in the cotyledon/embryonic leaf have been fully used by the plant and they shrivel up and die. Once planted in my pots I give her 3/4 strength nutes for around a week, then full strength nutes from then on. Now I say 'full strength' but this is not full strength as per the manufacturers recommendation as I've found that their recommendations is simply too strong for my setup and I end up with burnt leaves. Full strength for my setup is around 1400ppm, anything stronger and I have a marked decline in plant health.

 

Hope it helps

Merl1n

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Good advice from merl1n, I am also working on a seedling now, first 2 weeks I gave it 1/4 strength nutes right from the beginning which was ~250ppm, now after almost 2 weeks I've upped that to 1/2 strength which is around 500ppm and in another week or so I'll bump it up some more. I'd be a bit concerned if they have not changed at all for a week, they should be slowly getting bigger leaves and after 2 weeks you should probably be working on your 4th set of true leaves. I find within 2 days of sprouting they are showing first set of true leaves, then a few days after that second set and after about a week or so, third set will start to appear. I took a pic of my seedling every day to track it's progress which I will eventually post up somewhere as I was having a hard time figuring out how far along my seedlings should be, so this might help others too. Good luck!

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I start mine off on light nutes, about 0.8 EC, and slowly start upping that once they get the 1st set of true leaves (3 fingers instead of just 1).  I also start under HID lights, Merl1n is right that it's overkill, but it doesn't hurt them so long as it's not too close.  I used to have a nice T5 light for seedlings, but when it died I just couldn't be bothered replacing it, upside is that there's no hardening off required on changing up to HID.

 

For the 1st week you won't see much activity above ground, it's all in the roots.  But at 1 week you really should have the cotyledons and the 1st set of serrated leaves, plus the next set should at the very least be poking out a couple of mm.   Were any roots poking out the rockwool when you transplanted?

 

Give them time and they'll get going.  I'm not a huge fan of rockwool, it works and for non coco hydro systems is a great way to start off, but in my experience some auto strains at least don't seem to like them and don't get going until they finish taking ages to push roots out of the cubes.  Could be that you have a sensitive strain?

 

Best of luck :peace:

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