Grow Diaries

 

FACE-OFF: 90W LED vs 125W CFL

The Kale and Lettuce starts were end-of-season plants that were obviously struggling to stay alive at the garden centre as the weather turned against them – not the most ideal candidates for the experiment but since it was the end of the summer, alternative candidates were very limited.
As it turns out both plant types grew well under both the LED and CFL lighting that was used with both the Kale and the Lettuce doing slightly better under the LED light than the CFL light. However, the differences in growth were small and could have been due to other factors other than the lighting, so don’t read too much into this result.

Day 0

Image showing Lettuce and Kale growth under LED versus CFL grow lighting on day 0 (i.e. when seedlings were repotted in larger pots)

Day 6

Image showing Lettuce and Kale growth under LED versus CFL grow lighting on day 6

Day 12

Image showing Lettuce and Kale growth under LED versus CFL grow lighting on day 12

Day 15

Image showing Lettuce and Kale growth under LED versus CFL grow lighting on day 15

Day 21

Image showing Lettuce and Kale growth under LED versus CFL grow lighting on day 21

Day 29

Image showing Lettuce and Kale growth under LED versus CFL grow lighting on day 29

Image showing Lettuce and Kale growth under LED versus CFL grow lighting on day 29 (picture taken from a lower angle)

*******End of Experiment *******


Grow Diary: 90W LED – Cucumber

Cucumber plants started from seeds have grown very well under LED lighting with the first signs of cucumbers appearing (see Day 29 below) at approximately 6 weeks after seeds were planted. Different plants have grown at different rates so some of the spectacular growth of some of the plants have been due to genetic factors, however all plants started have grown well under the LED lighting, showing no signs of any problems.

Day 0

Image showing Cucumber plant growth under LED grow lighting on day 0 (i.e. when seedlings were repotted into larger pots)

Day 7

Image showing Cucumber plant growth under LED grow lighting on day 7

Day 14

Image showing Cucumber plant growth under LED grow lighting on day 14

Day 21

Image showing Cucumber plant growth under LED grow lighting on day 21

Day 29

Image showing Cucumber plant growth under LED grow lighting on day 29

Day 44

Image showing Cucumber plant growth under LED grow lighting on day 44

The cucumber seed that generated this plant was from a Middle Eastern source and I am told that the cucumbers themselves do not grow more than about 10cm before they should be picked. This first LED-grown cucumber was just the right size so it was time to taste!

Image showing one of the cucumbers grown under LED grow lighting

Delicious!


Grow Diary: 90W LED – Luffa

Although the Luffa plants initially grew well under LED lighting, they began to slow down and look decidedly less healthy after 3 weeks of growth. It is not clear why they failed to continue growing at this point, but it did not seem worth keeping them going from this point on and the experiment was terminated. Any number of factors could have been responsible for the failure to continue growing including too low an ambient temperature or even unsuitable soil conditions, so it may not have been due to any inadequacy of the LED lighting. Anyway, further experimentation will be carried out with the Luffa plants in the future, so stay tuned…

Day 0

Image showing Luffa plant growth under LED grow lighting on day 0 (i.e. when seedling was repotted into a larger pot)

Day 7

Image showing Luffa plant growth under LED grow lighting on day 7

Day 14

Image showing Luffa plant growth under LED grow lighting on day 14

Day 21

Image showing Luffa plant growth under LED grow lighting on day 21

*******Experiment Terminated *******


Grow Diary: 90W LED – Cherry Tomato

Started from seed, the tomato plants have grown incredibly well under LED lighting. However, after about 6 weeks of growth, some of their older leaves have begun to curl up as a result of what can only be described as blockages forming within the leaf veins (see Day 29). It is not clear what these are and why it is happening, but all the tomato plants are exhibiting the same characteristics. One possibility is that the LED lighting is too intense, and prolonged exposure is causing some sort of metabolic disruption. The good news is that the plants continue to grow well making new healthy leaves that are compensating (at least for now!) for the loss of the older ones. We will have to see how it goes….

Day 0

Image showing Cherry Tomato seedlings which have been grown under LED grow lighting. Picture taken on day 0 (i.e. when seedlings were repotted into a larger pot)

Day 7

Image showing Cherry Tomato plants which have been grown under LED grow lighting. Picture taken on day 7

Day 14

Image showing Cherry Tomato plants which have been grown under LED grow lighting. Picture taken on day 14

Day 21

Image showing Cherry Tomato plants which have been grown under LED grow lighting. Picture taken on day 21

Day 29

Image showing Cherry Tomato plants which have been grown under LED grow lighting. Picture taken on day 29

Problem with the older leaves – blockages (red arrows) forming in leaf veins???

Image showing the curling leaf problem observed in the Cherry Tomato plants grown under LED lighting

Day 44

Flower buds look to have started to form (see picture below right)

Image on the left shows Cherry Tomato plants which have been grown under LED grow lighting. The image on the right shows the flower buds on the same plants. Both pictures were taken on day 44


Other Grow Diaries on the Web

The first thing that strikes me is that almost ALL the ‘grow diaries’ that you find on the web involve growing cannabis (in the States usually – I guess they are well on their way to legalising it). I don’t know about you but I’m not that inclined to grow cannabis here in the UK! However, if I ignore their growing accounts, then I think that we could miss out on some valuable growing data using LED grow lights. So just to be clear, I don’t endorse in any way the growing of cannabis, I merely point to their sites for the information that they provide using the LED lighting technology. Ok, disclaimer made, let’s get into it…

1. http://www.420magazine.com/forums/abandoned-journals/165822-led-grow-journal.html – Here is a very interesting account of someone’s experience using one of the G8-LED grow lights that are sold by Dorm Grow which I describe on my UK review page as one of the better lights out there. The author is obviously not growing true blueberry plants (just in case you are confused by the name) but a strain of cannabis that is called the blueberry strain. What is particularly interesting here is that the author demonstrates one of the useful characteristics of LED grow lights that I alluded to elsewhere, namely that positioning your LED grow lamp can determine the size of your resulting plant. In this case, the author has mistakenly placed the lamp too close to the plants, initially stunting their growth. The author then uses the 450W LED lamp placed further away, which results in sudden spurt of vigorous plant growth. Key take away here:  450W G8-LED grow lamp should be placed about 1m above the top of the plant canopy to get good growth.

2. http://www.rollitup.org/led-other-lighting/508900-4-kessil-h350-600w-hid.html – I thought this was an interesting comparison of the differences one might get using different light sources. Once again, it looks like they are using cannabis plants, and for their LEDs, they use four  ‘professional’ 90W Kessil lamps (360W total), in this case the ‘magenta’ variant which incorporates a 4-band spectrum of blue and red with a focus on the red bands.



Using these LED grow lamps, the author  was able to get a much darker green (and healthier-looking I might add) plant than with a 600W HPS lamp. This probably has to do with stronger induction of chlorophyll pigment in the plant leaves, which is likely to make the plant far more metabolically active and have more energy for the tasks (eg. fruit production, etc) that we would like them to perform . Key take away here:  Focusing on specific light wavelengths (i.e. using LED lighting as opposed to more conventional artificial lights) can optimise plant metabolism.

3. https://www.icmag.com/modules/Journal/viewentry.php?journalid=631 – This grow diary is the type of study that is most sought after – comparing two different lamps side-by-side, in this case a 345W HydroGrow LED light vs a 330W LumiGrow LED light. Wattage-wise they can be assumed to be the same but interestingly the author gets two strikingly different results. The ‘experiment’ is well-controlled since the plant used in each set-up is a clone, and they are kept in identical conditions apart from the lighting (with a reflective wall separating the two sets). The LumiGrow light is the clear winner here, however, one should note that the HydroGrow light looks from the picture to be an older model (their current models have fans that are positioned differently and they don’t currently sell a 345W model). Key take away here:  LED Grow lights from different companies can give very different results (doh, I guess we knew this already, but it’s nice to see it in practice).

to be continued…

 

 Posted by at 5:30 pm