Onion seeds

**Alison** · 14-01-2015, 05:15 PM

They shouldn't need heat now they're through so I'd take them out - they'll get better light that way.

**Bohobumble** · 14-01-2015, 08:47 PM

Originally posted by Elfeda View Post

Well, sowed onions in small trays in heated propagator indoors this sunday evening and I can see some sprouting on 3 rd day. I have been switching on/off the propagater, some times during nights as well.

What should I be doing now? when should I take out from the propagater.. shall I put the heat on during nights only or all the time before I take out from the propagator.

Well that has decided it then, mine are doing nothing in my unheated greenhouse, I shall bring them home into the warm (no propagator sadly) for a few days on the windowsill!

**Elfeda** · 14-01-2015, 09:07 PM

I set the propagator on kitchen worktop next to gas cooker. looks few started appearing, removed the heat and on the worktop light just under the cupboards. hope this will do.

**Kristen** · 15-01-2015, 07:05 AM

Originally posted by Elfeda View Post

on the worktop light just under the cupboards. hope this will do.

I doubt it, needs more "lumens" of light than you get from a regular light source (e.g. the sort of light you get from multiple bulbs in a lighting-rig, or a more powerful growing lamp with a reflector).

Assuming the light is cool (temperature-wise) then put the plants as close to the light as possible - 1" or so is fine, provided they don't overheat.

Almost certainly more light on a windowsill than a simple/single light source, the later is likely to keep them on tick-over, rather than promote active growth.

**Jay-ell** · 15-01-2015, 10:27 AM

Not to nitpick but it's technically not the lumens that's important as this is a measure of the total visible light whereas plants need light within specific wavelengths (IIRC 400 and 600 nanometer bandwidths) so it is possible to have a high lumen light source which gives little light is these bandwidths.
I can't remember which bandwidth is best for vegetative growth and which for fruit v& flower, someone who has experience of using grow lights may be able to give better quality of than me

**Kristen** · 15-01-2015, 11:14 AM

Originally posted by Jay-ell View Post

Not to nitpick

No problem, I was over simplifying.

I can't remember which bandwidth is best for vegetative growth and which for fruit v& flower, someone who has experience of using grow lights may be able to give better quality of than me

Blue for vegetative growth, Red for flowering / fruiting.

That's a bit oversimplified too! although if using LEDs, rather than a broad spectrum light, then it is possible to have arrays of specific colours, so for growth I think (I've not used LED lighting rigs) predominately Red with some Blue is normally used; seems to me that with such a narrow band of wavelengths it is possible to have relatively low Wattage, but maximum impact on the plants. LED lighting rigs don't appear to me to be very bright, but unlike white-light if they are only providing the wavelength that plants need then that would be an efficient process.

**Jay-ell** · 15-01-2015, 12:21 PM

I vaguely remember from when I worked with visually impaired people that different types of light sources giving white light have different colour temperatures and are made up of red green and blue light of different intensity and in different positions in their section of the spectrum.

I never thought that just turning on a light was so complicated.

I've looked at some of the led grow lights but not been brave enough to buy yet. In theory as led would use less power they should also give off a lot less heat so can be closer to the plants. Couple this with their targeted wavelength then this might make up for the reduction in (perceived) brightness.

I saw on a couple of programmes the guy who built a fernery out of recycled bottles only to find out at the end that the green bottles he used filtered out the useful light. What a shame

P.s.

If it's blue for vegetation then this would explain why the led lights don't look as bright. Our eyes detect colour using structures in the eye called cones. Each cone can detect one colour with the cones detecting blue light being the LEAST numerous (les than 5 percent of the total number of cones IIRC) Once we strip out the green light(which the plants don't use) we've lost almost half the intensity we can detect. Ramping up the amount of blue doesn't make it look as bright as we aren't as sensitive to blue as we are to green.

**Aberdeenplotter** · 15-01-2015, 02:27 PM

I've used a couple of 20 watt low energy bulbs above onion seedlings and the onions did just fine. They do need some heat in addition though.

**Jay-ell** · 15-01-2015, 03:14 PM

I've been toying with the idea of buying some led grow lights and as I've just sown my onions I figure that if I'm going to do it it has to be now.

The problem is that I'm fiscally challenged (low wage, bank work and descended from a Fifer) so the ones that I can afford are 14w 225ish led lights on ebay for around�20 mark. Now I know that you get what you pay for, but anyone know if they'll do the job? Don't need for them to last for ever -a season or two till I can evaluate if it's worth buying a more expensive model (and save up the cash)

It was stated earlier that blue light is for vegetative growth however these lights are predominantly red leds - would they be okay for bringing on seedlings for a range of crops (eg onions, leeks, toms, chillies) or are they best used for fruiting and flowering plants?

**Spunky** · 15-01-2015, 06:50 PM

They seem expensive for what they are and you might need At least 2 are they 59.99?
You don't need red light if you're just bringing on seedlings, red would be more for growing a plant to maturity which you couldn't with them anyway because there not powerful enough

**chilli_grower** · 15-01-2015, 08:44 PM

I know a little bit about lighting (I am an electrical engineer). And I think that 'grow lights' are only beneficial if they are pumping out the LUMENS.

My theory is to achieve the maximum amount of lumens output, per single watt of power.

Colour temperature is measured in Kelvins, and I believe that a cool temperature is best for seedlings.

My current cool white LED E40 lamp, draws 65 watts of power, and pumps out 6500 lumens.

It is seriously bright, I can only look at it for a second and then have to turn away, as I begin seeing stars!

If a lamp is pumping out a low amount of lumens, then it would probably be just the same as using a windowsill...

I might be wrong though!?

But this is my theory....

Mine is very similar to this:

Goodlight 60W G360 LED SON Replacement Lamp E40 (Daylight) - LED G360 SON Replacements - LED Products - LED Eco Lights - Retrofit LED lamps and LED Lighting services specialists

**Bohobumble** · 17-01-2015, 08:07 PM

Originally posted by Elfeda View Post

I set the propagator on kitchen worktop next to gas cooker. looks few started appearing, removed the heat and on the worktop light just under the cupboards. hope this will do.

I brought mine inside a couple of days ago especially as snow and frosts were on the forecast, they are on the windowsill so above the radiator (who needs to spend out on a heated propagator?!) The seeds have started to grow!

**Kristen** · 18-01-2015, 08:01 AM

Be careful not too much warmth if they are on a windowsill - they won't have much light this time of year, and windowsill is much lower light levels compare to, say, a greenhouse.

**Elfeda** · 18-01-2015, 02:49 PM

I set mine at southfacing french door in living on a spare table.looks better.

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