Grow Light Advice

thirsty_dirt_77(3a)March 11, 2013

I've always purchased seedlings for transplant from my local greenhouse but this year have decided to grow my own.

Last year I purchased a 48" T8 Fluorescent fixture with a light reflector and Sylvania Gro-Lux 32W Wide Spectrum bulbs. My intent was to grow my own last year but time got away on me.

My question is this - are the bulbs I have sufficient for growing tomatoes, peppers & cabbage?

I have done too much research and have just confused myself. Please help!

Thank you!

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I use a similar set-up in my basement, but I use two 48" fixtures, side by side. Instead of true grow-light bulbs I use one cool-white and one warm-white bulb in each fixture -- cheaper and seems to work well. (Many years ago I used true grow-lights but the plants didn't grow well -- I don't know if they were throwing off some kind of light that was burning them or what was going on. But that was 20 years ago so they've probably sorted that one out with modern bulbs.) Keep the tops of the plants within a couple inches of the bulbs for best light.

I've never tried cabbage under lights but have started broccoli -- unfortunately for them they had week stems and succumbed to wind damage pretty quickly when moving them outside. Peppers do extremely well under lights and I often grow hot peppers to maturity in the winter for something to grow. Tomatoes do extremely well for about 6 weeks, after that they quickly get leggy and weak so plant them 6 weeks before you intend to start hardening them off outside. BTW, the lights, at least the lights I use, give them no UV light (maybe true grow-lights do?) so be very careful when moving them outside because it would be like a person living in a cave all their life and then suddenly going outside to tan in the early summer sun :)

    Bookmark   March 11, 2013 at 2:11AM
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bdgardener(3 AB)

Good advice, I start annuals, perennials, and veg. Also make sure they are getting 12-14hrs of light. I have mine set up on a timer, it just makes it alittle easier if you get busy. Cheryl

    Bookmark   March 11, 2013 at 8:04AM
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northspruce(z3a MB CDA)

You don't need full-spectrum. I'm sure Don's advice of one cool and one warm is sound, but I just use whatever and everything's been fine for the 10 years I've been planting indoors.

IMO it's more important to use new bulbs each year, keep them close to the plants and the environment cool after sprouting, and don't try to crowd too many plants underneath. One fixture will only light about 8" and anything outside that will have to lean in. Also, the outside four inches or so at each end a fluorescent bulb produces less light than the centre.

    Bookmark   March 11, 2013 at 8:43AM
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Hey Thirsty Dirt.

Be careful. I accidentally had about 115 tomato plants last year, LOL!

One thing I can suggest. Make sure you get yourself a small fan. Also, you can read until the cows come home on the growing from seed forum, if you have the time :)

Your Gro Lux tubes should still be fine for this year, but I wouldn't waste my money on more of them if you decide to expand. (Which you will) Go with what everyone here suggests.

    Bookmark   March 11, 2013 at 10:33AM
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Thanks for the advice everyone.

If my seed order arrives before the weekend I'll be starting everything very soon. I'm hoping to move stuff out the to greenhouse (if its completed!) mid may so I think my timing should be about right.

And nutsaboutflowers, I hear ya on the 115 tomatoes! When I purchased plants from my local greenhouse I always ended up with way too many plants that I couldn't bare to throw out.

This year my set up will allow me a maximum of 64 plants which will probably be way too much but it will give me a bit of leeway if everything doesn't do well.

    Bookmark   March 13, 2013 at 3:57PM
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motion will help tomatoes achieve a thicker stock,
and actually encourages increased chlorophyll levels

a slow fan for 5 mins. a few times a day,
increasing to 30 mins.
or if you don't have a fan, blow lightly, or simply brush with your hand

16-18 hours/ day light is optimal,
with 6-8 hours darkness for the plant to manufacture sugars for food

ward off damping off with weak chamomile tea or sprinkle cinnamon on the surface

    Bookmark   March 16, 2013 at 2:00PM
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Sometime ago Jim Hole wrote about grow lights in the Edmonton Journal. He advised using T5 tubes. I forgot the reasons but T5 is what I will use if I start seedlings or grow young plants. Did anyone else read about this?

    Bookmark   March 23, 2013 at 8:07PM
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northspruce(z3a MB CDA)

I guess the purpose of using T5 would be that they give more lumens on less watts. But they're nowhere near standard in North America and the bulbs cost more and I wouldn't even know where to buy a 4' ballast that took two bulbs. I have only ever seen them in short lengths for cabinet mounts etc. I have one for my fish tank canopy.

I use the standard 4' ballast with 40W bulbs because everything is cheap and readily available.

    Bookmark   March 24, 2013 at 10:35AM
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leftwood(z4a MN)

T5s will become the norm in the future. Many T12s and some T8s will begin being phased out this July in the USA. Of course, it's easy to find T5 ballasts on the internet, but at the moment, still difficult to find at a local store.

The advantage of having one warm white tube and one cool white tube is that each supplies part of the light wavelength spectrum that plants use - in the red, and blue ranges. The red light is used more to encourage processes related to flowering. Really not needed for growing vegetatively, but certainly doesn't hurt. For seedlings, you will probably get more growth from 2 cool whites, rather than one of each. Plants use more of the blue spectrum than the red.

You might find tubes that are rated at 6500K. They are essentially grow lights and might be within your budget.


    Bookmark   March 28, 2013 at 11:25PM
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Everyone's pretty much covered all your questions, so I'll just comment on the cabbage. I grow about four dozen brassicas every year (broccoli, cauliflower, cabbage and Brussels sprouts). This family of plants doesn't do well at all if they spend more than four weeks in a pot - that's from seed to final transplant to the garden, including time for hardening off. Brassicas that spend too long in pots will "button", not form a proper head. This weekend marks six weeks until the May Long. Because my garden takes a while to get into in the spring, I won't be starting any of mine until four weeks before the May long. If you're gardening in better soil or in a raised bed, you can go earlier, but not by too much. All the best! :)

    Bookmark   April 7, 2013 at 11:24AM
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