Auto grow: transition from CFLs to LED

ScotGrow

New Member
Hi everyone!
I'm a new member & I'm about to start a new indoor grow after encountering various growing issues.
I successfully grew feminised plants over the summer but have had much less success growing autos. Firstly, I used a Coco coir medium suggested on 'Mr. Canuck's' YouTube page, but the dry amendments used were sourced in the UK as 'Gaia Green' products are not available here. The method suggests germinating seeds in the medium in a 5 gal. pot. The amendments were too strong, some seeds rotted in the medium, others cracked the surface but their growth was extremely stunted. On the next grow I germinated the seeds using the damp paper towel method. No problems! I then placed the seeds in Biobizz light mix, which is specifically intended for seedlings. Once again, their growth was painfully slow & some could not shed their husks. I have now come to the conclusion that my LED lighting may be the source of the problem. I'm aware many say LEDs are too strong for young plants, but my SF2000 has been turned down to minimum output, hung 4ft away from the soil & with a diffuser placed beneath the light to bring the intensity down further.
Nevertheless, as these measures still seem to have failed, I have now purchased a CFL set up. Unless anyone here tells me otherwise, I will germinate the seeds in Biobizz using 2 x 100W CFL bulbs & switch on the LED once the plants have matured to some extent. Any advice you guys & girls can give me as to when & how I best handle that transition will be gratefully received.
Happy growing everyone!
 
I mean, I start my plants under COBs. I just keep 'em at around 30-36" for the 1st week or so. Always have.

The reason many say LEDs are too strong for young plants is because new growers seem to want to run full power 12" from their seedlings.
 
Thanks for the response '69. Unfortunately I'm still having problems in spite of the light being at min output & 4ft away!
 
Cannabis can take high light levels from the start, don't know what's in your mix or watering habits though.
 
So the mix drains well in your experience? Are you using seeds? Are they old stock? What's your temps and rh?
Psuagro! Thanks for showing interest. The mix drains pretty well & I'm certainly not over-watering. Maintaining temps of 20 to 24c & humidity between 60 & 75%. I have to use a humidifier as the plasterboard room absorbs moisture quite quickly. I grew from seeds supplied by a seed bank in UK & germinated in damp kitchen towel immediately after receiving them. After a week of poor growth I changed over to CFL lights & the seedlings definitely responded positively. However, their early trauma & profound lack of growth has set them back too far, so I'll be ditching them & planting 6 more auto seeds soon. I'll start them off using 3 different types of soil (2 in each). I intend to germinate them in the soil this time as I'm told it's best to disturb autos as little as possible during their lifetime. They will be moved into bigger pots at the appropriate time. I'm sure the new seedlings will flourish under the CFLs. The question remains on when I move them under LEDs & at what output.
 
Psuagro! Thanks for showing interest. The mix drains pretty well & I'm certainly not over-watering. Maintaining temps of 20 to 24c & humidity between 60 & 75%. I have to use a humidifier as the plasterboard room absorbs moisture quite quickly. I grew from seeds supplied by a seed bank in UK & germinated in damp kitchen towel immediately after receiving them. After a week of poor growth I changed over to CFL lights & the seedlings definitely responded positively. However, their early trauma & profound lack of growth has set them back too far, so I'll be ditching them & planting 6 more auto seeds soon. I'll start them off using 3 different types of soil (2 in each). I intend to germinate them in the soil this time as I'm told it's best to disturb autos as little as possible during their lifetime. They will be moved into bigger pots at the appropriate time. I'm sure the new seedlings will flourish under the CFLs. The question remains on when I move them under LEDs & at what output.

Seems like your ambient isn't too blame for poor performance. Have you tried the fixture closer and full blast? 16 inches or so? 4 ft is too far with a sf2000 imo. Remember outdoors their getting hit with 2500 umol/s midday from the start.

Also what's your water quality=using ro, filtered, tap?
 
Seems like your ambient isn't too blame for poor performance. Have you tried the fixture closer and full blast? 16 inches or so? 4 ft is too far with a sf2000 imo. Remember outdoors their getting hit with 2500 umol/s midday from the start.

Also what's your water quality=using ro, filtered, tap?
What am I missing, isn't around 27-29C the consensus under LED?
 
Seems like your ambient isn't too blame for poor performance. Have you tried the fixture closer and full blast? 16 inches or so? 4 ft is too far with a sf2000 imo. Remember outdoors their getting hit with 2500 umol/s midday from the start.

Also what's your water quality=using ro, filtered, tap?
I should also mention that the "SF2000" is a bootleg version bought on eBay. However, the diodes are the real thing & the seller has sold a few of them & there have been no 'negs' from dissatisfied customers. The output is variable but there are no markings on the dial, so when I'm trying to set the light levels it's a bit of a guess. I've noticed many growers advise not using LEDs on young plants (certainly not in the first 2 weeks). Yes Psuagro it's possible I've set the lights on too an output due to all the warnings I've had on LEDs. On this grow I'll use CFLs for the first couple of weeks, then switch to the SF2000. Do I need to get myself something along the lines of a PAR Meter to accurately measure LED light levels?
 
Unless you're adding infrared, your ambient temperature should be higher than with other light sources. I actually added some low efficiency LED bulbs into my tent just for the heat lol.
 
Sorry, don't use metric regularly..... I've run in that range with no issues before. Just have to alter watering habits. Doesn't mean it works for everyone though.....

But yes, over 80f is recommended with LEDs as the sole light source in here.

What about your water quality?
 
Thanks for the comment 1212, but that's news to me. 80 to 84F?.......phew that's hot!!
That's the sweat spot with LED, they don't have infrared to raise leaf temps above ambient like HPS/MH. I can assure you LED isn't your problem and cool temps will definitely slow growth. I think a fully dimmed SF2000 at 4 feet and cool temps are a problem, but there could be additional factors.

CFL is also fine for seedlings, but you don't need anywhere near 200w. I'm guessing that's equivalent wattage, ACTUAL wattage is the only one that matters. A typical screw-in led that is equivalent to 60W incandescent is actually around 9w.

A $15 lux meter is a great tool, check out this post by RB.
 
A belated Happy New Year & especially to those of you that have tried to help me with my grow. I have now reversed my plan to ditch this grow as the plants have recovered sufficiently under CFL bulbs. I've now moved them to 5 gal. fabric pots (60% Biobizz light mix, 40% coco coir, plus the dry amendments mentioned in my original post) & they are now under my SF2000 LED (2ft away & approx 60% power) with CFLs still in there to assist the transition & because I can't the temp above 25deg C. The photos I've attached show my general set-up of all plants, plus 2 shots of sick ones. The problem with the 2 plants are similar but the Bloody Skunk is not in good shape at all, although it is the tallest of all the plants. I've checked examples online & can't find anything similar, especially the distortion & paperiness of the leaves. The Blackberry Kush is in much better shape but the slightly mottled appearance of the leaves is similar to the Bloody Skunk. The 5 other plants are all ok, which is strange as they've all been grown in exactly the same conditions. I hope your grows are going well & I look forward to reading any suggestions you may have.
 

Attachments

  • General view.png
    General view.png
    1.8 MB · Views: 7
  • Bloody Skunk.png
    Bloody Skunk.png
    2.1 MB · Views: 8
  • Blackberry Kush.png
    Blackberry Kush.png
    2.1 MB · Views: 6
Back
Top