grow kit for classrooms

[catocorky3]

Hello, my wife and I are somewhat new to growing indoors and want to teach ag in the classroom to school kids. The teachers don't have much money so we want to start with a plastic tub filled with good soil that has perhaps a clipon light or other low cost growth light. We want them to be able to grow a few carrots, onions, leaf lettuce and radishes. We also prefer a light that is not so intense that it could be harmful to their eyes. We can consider building a reflective tent to go over this. This would be a starter kit that could lead them on to bigger things as they develop skills and interest in growing indoors
Thanks!

[The_Mouse_Police]

Get a >80 CRI 4000k Edison bulb (I'm partial to Hyperikon's non-dimmable ones) and a clamp light. Carrots, parsley, green onions, radishes (several varieties go from seed to maturity in under a month), and some others, need fairly low light. If you use a white bucket, and get the reflector right to edge, you could even grow basil, thyme, oregano, etc. with a single 60W equivalent bulb. Several brassica greens can be grown as baby greens, too, like bok choi and spinach, under low light.

[catocorky3]

thank you for the response and info, I noticed a GE 5000k bulb that pulls 13 watts for about $9 and also a hyper touch 48inch fluorescent daylight that pull 45 watts and claims a 5000 lumen output, fixture and tubes for $23. I believe these will also function to grow vegetables in a classroom without being too bright, your opinion?

[The_Mouse_Police]

Skip fluorescent. White LED have better spectrums. Higher CRI will tend to have more cyans and deep reds. If it has no CRI rating, assume it's low. The big light companies make good ones, but brick and mortar availability can be iffy, and specs on consumer models are often lacking.

LED tube replacement units are fine, too, just with the same color caveats, once doing anything bigger than baby greens. 3500K and 4000K tend to be a good balance for a variety of plants, but are often scarce at retail. 5000K, and 3000K and under, will be more likely to make tiny plants, or weak leggy plants, respectively.

These lights you see everybody putting together for pot, and all the popular panels with single SKUs of LEDs in them, are all 80+ CRI commercial indoor lighting LEDs, and they all have similar spectrums at a given color temp. There are minor differences in what might be ideal output spectra, but for the most part, the same kind of light used for pot is good for greens and herbs, at like 1/4 the power.

https://www.amazon.com/Hyperikon-Equiva ... th=1&psc=1

That would be an example of a pack I might get for doing mint family herbs. They have a cheaper 90 CRI 4-pack of 60W equivalents, that would do well enough for small greens, too. Dimmable often flicker, so I try to stay away from them.

[catocorky3]

This is great information, thank you for the input!
There is an LED 48" shop light that claims 250 watt equivalent, draws 45 watts, daylight non-dimmable, 5000 lumens, color temp 5000K and CRI 85 (also efficacy 111). Is this not a good grow light perhaps because it does not have correct spectrum intensity? In other words it does have CRI 85 but is weak in some of the spectrum? Is that also why 3500 and 4000k are better than 5000 and 3000K?
Sorry for all the questions but we need to know before setting these up in classrooms where the kids and instructors will hopefully be drilling us with these kind of questions

[TacticGuy]

This is great information, thank you for the input!
There is an LED 48" shop light that claims 250 watt equivalent, draws 45 watts, daylight non-dimmable, 5000 lumens, color temp 5000K and CRI 85 (also efficacy 111). Is this not a good grow light perhaps because it does not have correct spectrum intensity? In other words it does have CRI 85 but is weak in some of the spectrum? Is that also why 3500 and 4000k are better than 5000 and 3000K?
Sorry for all the questions but we need to know before setting these up in classrooms where the kids and instructors will hopefully be drilling us with these kind of questions

3000k has more red in the spectrum, and lower on the blue, thereby better suited for flowering\ fruiting.
While 3500k and arguably 4000k is more of an alrounder, where they work for both flower and vegetative stage(more blue and red in both)
Where 5000k has more blue(blue-white light) and is best suited for vegetative stage.
What is better of those is very much up to what you use them for, and in what stage they are growing in, if you want something that works for both, i would recommend 3500k.

[catocorky3]

once again thank you! I'm still wondering about the LED 48", I have one in my shop, they don't cost much, run cool (no fans needed) and claim to have a CRI of 85 and 5000 lumens. These also have a three prong power cord and therefore easy for a classroom teacher to setup and use. Will they work if positioned over two or three tubs of onion, carrot, lettuce?

[The_Mouse_Police]

If the red / blue ratio isn't too skewed, they could work well (IE, CCT). You might even need to filter it a bit for seedlings. Chances are that if it lists CRI, it should also list CCT. If that's off too much, the same people probably make one in a 3500 or 4000K, which are both very common for office and commercial bay lighting, however uncommon for home lights.

[PeteR_1]

Realize that this is an old post, but this info may be helpful to someone...

The 5000K - 5000Lm Hyper Tough is more than adequate for Seedlings, Cuttings and Early Vegetative growth with spectrum comparable to some Commercial Grow Lights but 4000K LED provide a better Spectrum Wavelength Distribution (B-G-R %)...

PC LED Spectrum Distribution compared to Commercial LED Grow Lights

Some highlighted details from; https://www.cpl.usu.edu/images/photobiology.png

https://www.cpl.usu.edu/images/photobiology.png

Hyper Tough 5000-Lumen LED Shop Light 5000K ($22.00)
The Integrated LED Shop Light has surprising performance, can cover an 8 in x 48 in area at 12 inches above the canopy for propagating seedlings and cuttings. Has two rows of 184 diodes (2835 LED) each under clear domed covers (1/2 tubes) and is ETL Rated for "Damp" Environment.
https://www.walmart.com/ip/Hyper-Tough- ... /303464059

Hyper Tough Integrated Shop Light 45 - 50 Watts / 5000 Lumens

17000 Lux (238 PPFD) @ 6.0"
9500 Lux (133 PPFD) @ 12"
6100 Lux (85 PPFD) @ 18"
4000 Lux (56 PPFD) @ 24"
2200 Lux (31 PPFD) @ 36"
54 Watts 120.5 VAC, 60.5 Hz, 0.83 PF, 0.54 Amps.

Required Light Intensity PPFD;
PPFD 100 - 200 (umol/m2/s).. = Seedlings and Cuttings (6700 - 13400 Lux @ 0.015 factor)
PPFD 300 - 500 (umol/m2/s).. = Vegetative Growth (20000 - 33400 Lux @ 0.015 factor)
PPFD 600 - 800+ (umol/m2/s). = Flowering and Fruiting (40000 - 53400+ Lux @ 0.015 factor)

Typical Phosphor Converted (PC) LEDs at 80 CRI are more than adequate as plant grow lights and are used in Commercial Grow Light Fixtures as;
5000K - Vegetative
4000K - Full Cycle
3000K - Flowering / Fruiting
Hubbell Cultivaire... https://www.hubbell.com/hubbellindustri ... /p/2056667

Lux to PPFD... viewtopic.php?f=15&t=5756
5000K = Lux (Lm/m2) * 0.014 (PPF/Lm)
4000K = Lux (Lm/m2) * 0.015 (PPF/Lm)
3000K = Lux (Lm/m2) * 0.016 (PPF/Lm)