Hyper Tough 4' LED shop light from Walmart (5000 lumen 5000k 45w)

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I've had bad experiences with the flood light type LED grow lights so I recently bought this cheap LED light from Walmart to start my vegetables with. I've been playing around with it with some test vegetables to gain some insight before giving it a go in the Spring.

I rigged up a light sensor out of an old Moultrie game camera to a multimeter that gives me an ohms reading with light intensity. With the setup out of the sunlight and the sensor in place, I move the bulbs up and down and test the readings.

I realize this does not allow my readings to be compared to anything else other than what I test with my meter so for a comparison I have tested:
Outside Full Sun: 0.8 kOhms.
Outside Shade: 6.0 kOhms.

DISTANCE FROM TOP OF SOIL	SENSOR ON EDGE OF FLAT	SENSOR IN MIDDLE OF FLAT	NOTES
1.25"	235.0 kOhms	1.8 kOhms	Hood too close and shading the edges of the flat.
2.5"	9.4 kOhms	2.7 kOhms
3.5"	8.5 kOhms	3.4 kOhms	Seems to be optimal distance for edge and center readings (whole flat).
4"	8.5 kOhms	4.0 kOhms
5.5"	8.5 kOhms	5.1 kOhms
7"	9.0 kOhms	6.2 kOhms
8.5"	9.9 kOhms	7.3 kOhms

I've had the bulbs 3.5" away from the soil for about two weeks now. The setup is sitting in a southern window for extra light which has been about half sunny and half cloudy so far. I turn the lights on when I wake up and open the curtains and turn the lights out when I go to bed.

Even though the readings say they are slightly shaded these tomato seedlings don't appear leggy and are growing towards the bulbs and not the sunlight but I think the sunlight must be helping them. I'm not sure if the bulbs would produce enough light on their own without some sunlight to back them up. But as the seedling grows towards the bulbs they get more light and so far it seems like they are happy but that could change as things progress.

I did previously remove a couple tomato seedlings that were a bit leggy on a higher distance and have recently started test cucumbers which haven't emerged yet.

 

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One thing I have noticed is that the normal amount of fertilizer I am used to giving seedlings is not enough nitrogen for this inside starting of seeds. Ambients temps are consistant of about 74F. The leaves are a pale green color, not too bad but I can tell. I am used to starting my seedlings outside in the sun or in a mini greenhouse and I have learned what amount of fertilizer works for that. Not sure why because I usually start my onions Feb 12th where the natural sunlight is short lived outside anyways so surely that cant be the reason. The soil does stay damper longer inside so maybe that is why, but that doesn't make sense to me. I do blow a fan on them about once per day to help with evaporation and fungi avoidance.

 

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At this point they seem to be doing pretty good. Better results than what I've had with the flood light grow bulbs. They aren't leggy. Nitrogen input or uptake still seems a bit low. I gave the cucumbers 200 ppm N as soon as the baby leaves flattened out so I'll see if that does better than what I gave the tomato seedlings to start with which was 30 ppm N.

 

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The light seems to work well if I place it 3.5" above the soil and turn it on when they sprout and then raise it again when the plant is 1.5" from the bulb. This is still inside a southern facing window that has a tree that shades the window somewhat midday this time of year.

I decided to start over fresh with some pepper and tomato seeds to see if I can do better with the fertilizer which was lacking a bit at an early age on the previous plants.

 

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These are my newest pepper subjects. I think I fed them just a little too much nitrogen but still happy with the results. These are the best looking peppers I've ever started indoors.

So this walmart light does work just fine for starting plants indoors. I'm not sure if it works good for the flowering stage or not though but I don't need it to. Two flats can fit under it. I recently saw a Gardening name brand grow light that only one flat fits under for like $40. I just giggled at it.

There is one thing I learned. Growing seedlings under a grow light, in a direct sunlight window does not work good. The leaves bend and twist in a weird manner light they dont' know which light to stare at. I blocked out the direct sunlight from day 1 with these plants and now they grow like what is pictured.

 

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A problem I'm finding is when the top of tomato plants get to about 2" away from the lights, the leaves start to curl under themselves in a bad way, trying to avoid too intense of light I'm guessing. If you let it go on for too long, they curl too much and want to twist and carry on and it is hard to get them to straighten back up. I may have blamed that on sunlight interference before, I don't know now. You definitely want to move the lights up when they get 2" away from these lights.

I haven't noticed pepper leaves curling under like that, but they grow slower than tomato plants and are further away from the lights. I have noticed pepper plants seem to be more compact like the picture in the post above. Maybe too intense of light holds them down like a hand on a jumping dog?

Anyone ever have these problems?

 

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When the top of the plants get 2.25" away from the lights you are going to want to raise the lights. So far about 3" away or slightly more seems to be optimal.

 

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UPDATE ON THESE LIGHTS:

These lights have to be hung at the right height above the plants and this margin is pretty slim. Too close and the plant curls away in a disfiguring manner and they don't really straighten back up. Too far away and the seedlings get leggy. It can be a pain to keep plants at the correct distance as some grow faster than others so I have to set some cells on a makeshift riser to keep them all at the right height. I try to keep the top of the plant 2.5" - 3.5" away from the lights.

Also under constant LED lighting the undesides of leaves can begin to turn purple. Only the undersides. I can put them in sunlight and they will green back up after several days so I have found that the seedlings need some natural sunlight so I just take them outside on the warmer days. My guess is the LEDs are missing some type of light that natural sunlight produces.

Other than that this cheap Walmart LED has served its purpose for me and starting my seedlings. I'm going to use it next year too. I don't believe I would want to use it houseplants or vegetables that can only stay in the house.

 

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I bought a 4 foot Shop Light for my Seedlings in my Greenhouse and Heat Pads.

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