akgrow
Newly Registered
Posts: 2
Joined: Sat Dec 30, 2017 2:13 am

Help with new NFT system

Hello,

I'm looking for advice on my aeroponics system. I added a second LED grow light (the bright pinkish kind) about 2 weeks ago. The idea was to have a more even distribution of light across the plants. The growth exploded but about a week ago the tips of leaves started to wilt and now some are burnt/browning/and some leaves are yellowing.
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the larger plants are a 6+ weeks old
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The roots are growing very well and look good
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I've read this can be due to a mineral deficiency and that the solution could be raising the lights (I've done this) and adding a fan to increase airflow and transpiration.

The new starts also show darkening of the leaves. This is butter bib lettuce so I expect a bright green color.
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Thanks for any advice!

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MoonShadows
Senior Member
Posts: 149
Joined: Mon Dec 11, 2017 4:50 am
Location: Stroudsburg, PA - Zone 6a

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I had this happen twice in my indoor kitchen garden (not an aeroponics system). The first time I think it was due to heat from having florescent lights too close. Do you have additional heat-producing lights on these? The 2nd time, and this one took me a while to figure out, it was from salt buildup in the soil because I use a sodium water softener in my house. I read that even that little bit of salt can build up in the soil over a period of time. There was no way I could flush out the salt, so I replaced the growing medium and tapped my water supply before the water softener.

I have a question. Why did you add the red spectrum grow light? That is more useful for flowing and fruiting. The blue spectrum is more useful for vegetation growth? Just curious?

The blue light spectrum (430nm-450nm) is what is most needed for young seedlings and good vegetative growth. It encourages growth during the vegetative stage of their growth cycle, especially when “stretching” must be reduced or eliminated.

The red light spectrum (640nm-680nm) is the more important for flowering and fruiting regulation. These wavelengths encourage stem growth, flowering and fruit production, and chlorophyll production.

akgrow
Newly Registered
Posts: 2
Joined: Sat Dec 30, 2017 2:13 am

Hi! Thanks for the welcome.

Regarding heat - there isn't any additional heat. The room is around 68 and the temp measured under the lights is 72 or so. I did raise the lights about 6 inches to reduce intensity and lower potential for heat buildup.

Salt - I haven't gone so far as to use distilled water for the system and we don't have a softener but maybe it's the chlorine in the city water?

Transpiration - originally I didn't have a fan in the system at all. after reading that a lack of or low transpiration can cause both the burn and the "bubbly" leaf formation due to a lack of calcium transport to the leaves I added a fan. The immediate change is that I now have added water to the reservoir much sooner than before which is a good sign that transpiration has increased.

Lights - These are simply generic ones purchased off of Amazon. They do have blue led bulbs but maybe not enough? Link here: https://www.amazon.com/Roleadro-Galaxyh ... ight&psc=1

Thanks!

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MoonShadows
Senior Member
Posts: 149
Joined: Mon Dec 11, 2017 4:50 am
Location: Stroudsburg, PA - Zone 6a

Hmmmm...I don't know much about how chlorine might affect plants since I am on well water.

Thanks for the tip on transpiration and using a fan. I didn't know that.

I was using 2-T4 florescents and some cheap LED grow light strips I bought om Amazon and wasn't pleased. I burned through 2 DC adapters for the grow strips within a year. Hey, you get what you pay for. I watched an episode of the MIGardener where he talked about the HappyLeaf LED Grow Lights (https://www.youtube.com/watch?v=1emKxhU75aQ). The one he features covers a 1' x 1' garden. I looked at their website (https://www.happyleafled.com/) and was so impressed with the videos that I purchased a 33" grow light from them that covers my 4' x 1.5' kitchen garden. It costs $179, but I wrote them before I purchased it, and after about 2 emails back and forth, they offered me a 10% off coupon, so I only paid $161.10 (hint, hint) My lettuce, spinach and basil now look like they are on steroids. I have never had such dark, crispy greens and fast rate of growth in my kitchen garden. I saw that one you have on Amazon, but wasn't sure about it.

This is a picture of my kitchen garden the day I hung the Happy Leaf light
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This is a picture 9 days later
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