Best Indoor Lights for Starter Veggies ?

[PaulZone8b]

I have used 4 ft fluorescent garage lights in the past, with a 3000K bulb and 5000K bulb in the same fixture and worked pretty well, but those got too big and bulky for my indoor rack where I start all my 10x20 trays so I got rid of them. I bought an LED strips 3000K and 5000K and using them now, but not sure getting good healthy starts that I used to get....so not sure if it the lights or what.

What indoor lights do all of you folks use for starter racks for germinating and getting healthy starts for the garden ?
The fall veggies need to get started now indoors since its still too hot outside. I dont trust the ads on Amazon for "full spectrum" LEDs when they are just saying 5000K. That does not mean full spectrum. I know some LEDs have some "red" lights in the same strip with the white lights which is how they are getting the "warm" range in there I guess.

 

[Meadowlark]

I don't know about the "best" but I use these because they are very handy to locate where you need them and very effective in use.

The ad "The Bloom Lume full-spectrum LED lighting closely mimics natural light, supporting the photosynthesis process with its range of colors, much like regular sunshine. High-quality tubes are mounted on a sturdy clamp with a flexible gooseneck for portability and easy adjustment, enabling direct or indirect lighting at a wide range of angles."

 

[Chuck]

I grow vegetable seedlings from seed commercially. It is a small enterprise but it keeps me busy during the winter months in Texas. I have 2 stainless tables 4 ft x 4 ft. The lighting is 4, 2 bulb 4 ft. fixtures over each table. This allows for 8, 1020 flats on each table. The bulbs are T8 daylight white 3000K. The ends of each fixture is screwed to a 1"x4"x5ft board. The end of each board is attached to an overhead pully to allow easy adjustment of the lights over the plants. IME it is not so much the type of light nor particularily the strength of the light that is most important for fast growth, it is how far the light is above the plants. Second to lighting is the soil temperature, especially so during germination. I tape 4 ft. wide plastic sheeting around each table and heat each table with a cheap tower type heater from Walmart. There is also stand type oscillating fan for good air circulation. The actual room is 12ft x 14ft. When I plant the seeds I use the 6 pack and if and when I decide to transplant into a 3"x3" continer I have shelves mounted on 12" brackets. These shelves are lighted with cheap 2 foot shop lights, the kind that can be plugged into each other and the bulbs are not replaceable. By the time these plants are getting too tall for the shelves it is normally warm enough to take them outside or to the outdoor market where I sell them. I normally grow 48 1020 flats of 6 pack containers per season.

 

[PaulZone8b]

Thanks Chuck and ML. Chuck, can I ask what you use for starter mix? and ratios? I assume you bottom water once they germinate. Any amendments at seed stage or toddler stage ?

 

[Chuck]

Thanks Chuck and ML. Chuck, can I ask what you use for starter mix? and ratios? I assume you bottom water once they germinate. Any amendments at seed stage or toddler stage ?

I use the cheapest organic soil at Home Depot which is usually Kellogg Garden Organic. I mix 75% soil and 25% horse manure compost or chicken compost. When the plants (tomatoes/peppers) have 2 sets of true leaves I start watering them with Medina Hasta Grow @ 1/2 the rate once per week. When I do a normal watering I water from the bottom up completely saturating the soil. I just put the 1020 tray with the plants in it into a 1020 tray without holes and fill it up until water is standing on the soil, then remove the tray with the plants and let them drain. If some plants start to look droopy I always give them an extra day or two. If they are not looking any better 2 days after watering I mix up a gallon of SuperThrive and give each plant a watering with this from the top down on the third day after watering. I use a whiskey bottle and pourer for this and try not to get any liquid on the plant. If this treatment doesn't work I remove the affected plant from the tray and put this plant into my "plant hospital". But usually a sickly plant will recover with just the SuperThrive. Then there are the cases of just plain old genetic deficiency and I put these in the trash.
Tomato seedlings and cucurbit seedlings are more susceptible to foliar diseases than other types of vegetables. As soon as I plant the seeds I use a pepper shaker to sprinkle a light layer of Whole Ground Cornmeal or Horticultural Cornmeal on the soil surface. This is to enhanse the growth of Trichoderma, a fungi that eats harmful bacteria and fungi. The cornmeal is its favorite growing medium. Soil temperatures are really important to germination. I try to keep the soil at 78F during the ENTIRE growing process. I have the potting soil at 78F before I stick the first seed into the soil. Tomatoes usually take 4-6 days and peppers slightly longer except for the superhots which usually take about 8-10 days.

 

[Chuck]

BTW, in a smaller or different setup than mine you can get single, double or even quadruple bulb fixtures for 2 ft lights. I also forgot to mention that the T8 bulbs are NOT for grown plants, only for seedlings. I don't know about T5's.

 

[Buulder]

I think you’re on the right track questioning the 3000K/5000K labels. Color temperature by itself doesn’t tell you how much usable light the seedlings are actually getting. A cheap 5000K LED strip can look very bright to us and still put out considerably less light at the tray than the old fluorescent fixture did.

For starting vegetable seedlings, I wouldn’t worry too much about finding a fancy “full spectrum” grow light. A decent white LED shop light around 5000–6500K can work very well. What matters more is having enough light intensity and keeping the fixture fairly close to the seedlings. Extension recommendations are generally around 12–16 hours of light per day, with the light only a few inches above the plants.

Since you’re using 10x20 trays on a rack, I’d also look at the actual wattage and coverage of those LED strips. If the seedlings are getting tall and thin, with lots of space between the leaves, that’s a pretty good indication that the new lights simply aren't putting enough light on the plants. In that case, adding another strip or moving the existing ones closer may make a bigger difference than changing from 5000K to some expensive “full spectrum” fixture.

I used to think the same way about mixing warm and cool bulbs. It does give you a broader spectrum, but for young vegetable starts I’d put more emphasis on light intensity and coverage than on getting the exact color temperature right. A simple white LED fixture that actually delivers enough light can outperform a “full spectrum” light that's too weak or mounted too far away.

If you still have the old fluorescent setup's specs and know roughly what the new LED strips are rated at, I'd compare those numbers first. That might explain the difference you're seeing with your starts.

 

[Meadowlark]

For starting vegetable seedlings, I wouldn’t worry too much about finding a fancy “full spectrum” grow light. A decent white LED shop light around 5000–6500K can work very well.

That is some good input. I really don't know what is "best" so I did some AI research. First, I asked what was the "best" W for growing seedlings. The response was :

Why 6000K Works for Seedlings​

Seedlings need:

• Bright, cool‑white light (5500–6500K) to mimic spring daylight
• Even coverage to prevent leaning/stretching
• Moderate intensity (too strong can scorch tender leaves)

Next, I asked AI for the "best" 6000W product and received this response:

Comparison Table (Seedling Performance)​

Product	Type	Coverage	Best Use	Price	Rating
Garpsen BL‑G40A Panel	Panel	Wide, uniform	Seedling trays	$16.99	9.4/10
GooingTop Clip Light	Clip	Small area	Small trays	$20.99	9.1/10
GooingTop Dual‑Head	Dual clip	Medium	Multiple pots	$19.99	9.0/10
Garpsen 80‑LED Floor	Floor stand	Medium-large	Shelves	$19.99	8.7/10
Kullsinss 3‑Head	Clip	Medium	Mixed pots	$25.99	8.5/10

I found this interesting...and the one I use and recommended to @PaulZone8b is rated second on that table list above. All are very reasonably priced.

 

[Chuck]

I have tried the 5000K-6000K and although they work fine for larger seedlings IME they are just a bit too much for freshly germinated seedlings. Once the plants have a minimum of 3 sets of true leaves is where they really shine. With the 3000K you can keep the light closer and not have to worry about burning and on the 5000K-6000K you have to maintain a much closer watch on light distance especially at the cotyledon and the beginning of the first set of true leaves. And on the color of the bulbs between the Daylight White and the Cool White I have not seen any measurable differences.

 

[Meadowlark]

I have tried the 5000K-6000K and although they work fine for larger seedlings IME they are just a bit too much for freshly germinated seedlings.

I haven't found that to be the case here. No burning at all with the seedlings I do, and I set the lights pretty close to the freshly germinated seedlings.

Right now, I have broccoli, Brussels, Kale, and Cabbage plants just about ready to set out in the garden. Several are in "conditioning" to get them ready for the heat and humidity they will soon face.

 

[Meadowlark]

I think you’re on the right track questioning the 3000K/5000K labels.

That's an interesting observation. During my AI research, AI volunteered that many (most) of the labels on those numbers are not at all accurate. Interesting.

 

[Buulder]

That's an interesting observation. During my AI research, AI volunteered that many (most) of the labels on those numbers are not at all accurate. Interesting.

Yeah, that wouldn't surprise me at all. I think the bigger issue is that people see 5000K or 6500K on the package and assume they know exactly what they're getting, whenn there's a lot more to the actual light output than that number.

It would be interesting to compare a few of these inexpensive LED strips with a light meter and see how close they actually are to their advertised specs. I suspect some of the differences people notice between fixtures have less to do with the Kelvin rating and more to do with the actual output and spectrum.

 

[nao57]

What I've noticed is... when it comes time to move stuff outside after growing inside, you have to transition very carefully to avoid losses. A lot of this is because the outside humidity is super low compared to inside. And then the temperature swings. If we don't manage that part carefully we'll lose tons of plants.

So the first day outside might be only 1 hour. Then just add a half hour every day...

...

For grow lights... I think a lot of them say its supposed to last for 20,000 hours for the life of an LED grow light. But I'm not sure if people have proven those claimed numbers. I use whatever I can get on sale, not sure what's best.

 

[Meadowlark]

What I've noticed is... when it comes time to move stuff outside after growing inside, you have to transition very carefully to avoid losses.

This is very true and most commonly the transition from inside is from warm to colder temps.

However, the transition to hotter temps is just as critical if not more so. I never see anyone write about it...except me but gurantee it is critical.

Starting seedlings at 72 deg. f and then transplanting them into 100 deg. F plus is as challenging if not more so than the reverse. It requires slow slow going.

If you want a successful fall garden here in this climate, you must learn how to do that key transplanting step.

 

[cpp gardener]

The temperature of the light (3000 or 6500) indicates the spectrum, while the lumens is the actual amount of light produced. A higher lumen 3000 light is better for growing plants than a lower lumen 6500 light. Go for the highest lumen rating you can find.