I have been having problems getting seeds started. I am using White Widow seeds, germinating them and planting them in 4 inch pots with seedling soil, then keeping them in a south window until they get about 4 rows of leaves on them (about 2" tall). Then I have been moving them into my grow tent under a 450 watt LED set to veg (about 36" off the plants). Within a couple days, the lower leaves start falling off and they eventually turn into 2" sticks (dead). I gave a couple to a friend before they died and he put them under a fluorescent grow light and they snapped out of it. Is this a problem with my LED light? Should I keep them under another light until they get hardier? Thanks for any help!
I’m curious to hear any thoughts on this as well. What does the LED manufacturer say about distance from plants? It is my understanding that each LED manufacturer has an ideal suggested height from the plant, which varies by brand.
In my own reading, before I purchased my LED, I also found this to be true. Some manufacturers claim 20", while others say higher or lower.
Could the added nutrients be a contributing factor? I hope some folks with greater knowledge chime in, as this is a very good question.
Which brand of LED are you using? Does it have a Veg / Bloom switch?
Are you sure that flies or bugs are not eating the nodes? Causing leaves to fall off. It happens.
The light I am using is a Platinum LED P450 unit. I called the company when I got the light and this is what they told me for height from the plants:
- For seedlings or very early growth, go for 36" with the veg switch only
- once they mature a little, go down to 24" and stay there… veg switch only
- once you move to flower, go both switched and 18"
I am not using any nutrients at this point. I have never seen any bugs in the room, but am not saying that is not possible. The plants are not being eaten, they are just shriveling up. Also, this has only happened with the White Widow seeds. I have grown other seeds this same way with no issues.
Soil can be a factor also , but with my Led from advance I start right at 12 inches above the soil until the seedling comes up , once the leaves open to used light , I move my light to 28 inches turn my blue light switch to about half , and the red flower switch on but just on until the second set of leaves grow . As the plant progress , I move the light 4 inches towards the plant and after the third set of leaves , I turn off red light and used only blue light at 3/4 on the switch , this is my way that has worked successfully for me but I start my seedlings in coco coir , only ph water at 5.8 foliar spray , misting the plants only , don’t spray directly , stem is not strong enough . After third node top plant , let the next node grow on each side , than give a very small dose of super thrive and cal-mag , only 2.5 ml in a liter of ph water at 5.8 , than once the coco dries a bit on top , transplant it to its final bucket . But before I put young plant in the next pot , I flush my soil with ph water until my run off is 5.8 -6.0 than I put the plant into soil and it should do fine . Out of five grows this method has work consistently , no stress to the plant four times . The time it failed , is when I transplanted seedling directly in fox farm ocean forest without flushing first and the seedlings died two weeks after transplant , so I started checking run off in any fresh soil I used before I put plants in it . I’m no expert but this is my selected method that works for me .
Based upon your input, not only do I continue to find this an interesting topic, but also have legitimate tie-ins.
While I am in the very early stages of germination, my Platinum LED 600 arrived today. I don’t have the proper hardware to hang it, so it’s still in the box. Additionally, I also wonder the correct time to switch from from T5 to LED…
In my shipping info, the one comment I noticed was the statement that, in the cases of the higher inensity lights, the adjustments may need to be tweaked.
I am interested to follow your thread, while leaving my couple plants that came to life, a time to live under T5. I look forward to future postings.
Kevin
**On a side note, I chose the 600 due to it’s footprint, as, even though I have a 1 meter squared tent, the 36x8 design offered the most flexibility in future upgrade for adding a second light. I coninue to watch with much interest. 
I think I need get a small T5 light to get the plants started. When I bought the seeds (from this site), they suggested putting 35watt cfls 2" over the seeds until they are hardy, So that is what I am going to try next. I think this will work better. The first grow I did, I left them in the sun for almost 2 weeks and they were much hardier when they went into the big pots in the tent.
This link is what was suggested when I bought the seeds – http://ilgm.co/germinateme
I have grown a lot of ww autos and they will turn yellow and die like that.
I have best results with a peat moss pear lite mix m. (ProMix)
I give them B1 with every watering (superthrive)
About day 7 I give them a high nitrogen nutrient
Then Every other watering until they start flowering
I used to think I was giving too many nutrients and that was my problem.
They like nutrients !!!