Grow lights, heaters etc, on a budget

Wish I knew what you were on about Clue but I've clicked "like" to be on the safe side ,
Jenny

 

Appreciate the feedback gents! So if I wanted to overwinter some non hardy plants, would you suggest an LED hydroponic one?

 

My one is showing good results so far, but it is still early days.

Oh, there is one other thing, if you want the plants for display while under the LED panel, you might want to consider some supplementary white light. The white light is not needed by the plant, it will just stop them appearing to be a murky brown colour. Plants are green because green is the one colour they don't want, so they reflect it. The LED panel doesn't waste energy supplying the colours the plants can't use, so under the lights the plants look almost a murky dull colour, because they are absorbing most of the light rather than reflecting it.

 

If you have some tall-ish plants then neither LED or CFL will be much good, as their light won't penetrate the "canopy".

People over-winter tender plants on tick-over by dangling CFL's above them (i.e. NOT attempting to provide an intensive light source) and keeping the temperature as low as possible so the plants don't make any/much growth. So a few CFL's dangling amongst the plants in a frost free, or slightly warmer [i.e. according to the plants' minimum temperature tolerance] garage or similar will do the job, and be cheap to buy and to run.

For active growth of a plant which needs canopy penetration you need Metal Halide.

For a reasonably large area (one or two square metres, or more) then the Watts (and thus running cost) that you need is about the same between Metal Halide and T5 tubes - bit less for T5, but not hugely so, so I think M.H. is a better choice once you get to that sort of area - because it will also do seedlings, which T5 is ideal for. Capital cost for M.H. / T5 is about the same (again once you get to a couple of square metres, or bigger).

"a couple of square metres" may well be quite a bit bigger than most hobbists need though?

LED also good for seedlings, but I am still sceptical that the number of LED bulbs needed to get enough Lumens [light "power"] for good growth is still a high initial cost. I have no doubt that both in terms of running cost, and the fact that the LED bulbs last "forever", that LEDs are the cheapest to run.

Worth a read of the Cannabis forums on the subject. Those folk are growing high value crops so have put all the time, effort and money into comparisons between the various types of lighting.

 

My panel was about £20, and so far the seedlings under it are growing string and deep green, as opposed to tall, weak and pale. The only light my seedlings have had so far has all come from the LED panel. Its still very early days yet, I've only had seedlings for a week, but early indications are all good.

 

That's good to hear. I have no idea how you measure the Lumens equivalent of LEDs. The LEDs are providing just the Red / Blue light components. That's what the plant needs, so to a certain extent the rest of the white light wavelengths are redundant, so it may be that you need LEDs that appear, to us, to be far less bright compared to white-light to get the same growth ... so maybe a straight comparison with a light meter would be useless?

I doubt your LEDs are chucking out 5-10,000 lumens, which is what I grow my plants under, for example?

 

Clueless1 - any chance of you putting a few spare tomato seeds in a pot under your lights to test how well they perform with them, as I'm sure that's the plant everbody will probably be the most familiar with and be able to compare early growth under LEDs both with other types of lights and later sown plants grown in natural light?

 

I have some tomato seeds somewhere. I'll give some a go when space becomes available. Already I'm feeling held back by the very limited size of my grow cabinet

 

I don't know how many lumens I get, probably far less than your lamp gives I have no doubt. But as you say, the LED array has the advantage of being able to use all the energy to produce exactly the right bandwidths of light, with no (measurable) loss through heat or unusable bandwidths of light.

The LEDs are also focused into a very narrow 'beam', so all the energy comes straight down (not sure I explained that right).

It is still bright though even to human eyes. If you accidentally look at it from just the right angle, it is like being whacked in the face. It really hurts your eyes. A few degrees off and it just looks like some useless novelty piece, but that's probably good because it means its casting all its light where you want it.

Another interesting observation I've made is this. My seedlings are virtually invisible under the grow light. They are not green because there is green light for them to reflect. The compost just looks empty. Lift the trays out to check what's happening and they miraculously appear, all string and healthy. I'm sure there must be some evolutionary advantage to plants appearing virtually invisible under certain colour of light. Don't know what it could be though.

 

I'm sure there must be some evolutionary advantage to plants appearing virtually invisible under certain colour of light. Don't know what it could be though.[/quote]


Yes the slugs won't find em

 

As far as my learning (so far) goes - plants have not evolved with humans in mind but insects who see differently to us - as well as being around long before we got on the scene. If I get this right, different colours reflect different amounts of UV and acts as the signal for the insect to forage or avoid.

 

The basic mechanics of plant life evolved when the earth still had an atmosphere that was very toxic to animal life as we know it. I suspect chlorophyll, (plant blood) which makes plants green, probably came into being before plants had to develop defences against creatures.

I don't know what evolutionary process triggered plants to not want green light. Red I can understand. Red light suffers less impedance so more of it can get through the a hazy cloudy atmosphere. Not so sure about blue, other than we seem to have a fair amount of it when the sky is clear

Plants can't use UV at all, it is too high energy. They reflect it in different measures to act as guides for pollinating insects that can often see just into the lower frequency end of ultraviolet, and often can't see the red end of the spectrum at all, hence they see things very differently to us.

 

Exactly what I meant!
I couldn't have put it better myself!
(Thanks, Clueless!)

 

I just thought I'd pop in an update/progress report/findings

The grow cabinet has so far proven to be a complete success. Seeds are germinating away at a good rate on the 'heat' shelf, then being moved to the 'light' shelf.

Quantity is lower than I'd hoped, but that's due to space limitations. I have two trays of 80 correopsis doing nicely, and last night a tray of 40 verbena went onto the heat shelf. I also have 20 small pots each with a Chillean Glory Flower seed in, 10 of which have germinated so far.

There is not enough room on the light shelf for all the seedlings at once. Prior to starting another tray last night, I'd started to rotate the two trays, 12 hours with one under light and one on the heat, then swap. We've had a couple of sunny days, on which the seedlings have been getting a bit of extra light by taking turns between the windowsill and the light shelf. Now the heat shelf is rapidly filling up with a new batch, the already germinated ones can no longer go onto the heat shelf for their 'induced night'. They will for the short term take turns between windowsills and the light shelf.

We're getting towards half decent daylight hours now, so I think there's little point expanding my kit just now. Over coming weeks the one LED panel will increasingly become a supplemental thing rather than the main light source. However, given the success rate I've seen so far, I'm already planning...

Project GC02 (Grow Cabinet 2).

This will build on what I've learned from GC01. It will probably be a custom built cabinet, as opposed to a retrofitted cast-off cupboard. It will be better insulated against cold (probably just made of chipboard and/or ply). There will be much more space, and the shelf size will be a direct multiple of a standard propagator size. I probably wont bother with additional heating, as the heat is only really needed to stimulate germination, and as that is quite quick, more light area is needed than heat area. I'll reuse my existing heat mat and LED panel, and probably get 3 more initially, but allow room for more as I've done with the current cabinet.

I'm going to fall short of my target of 1000 plants by the end of March, and that's largely down to planning oversights with the current cabinet. Nothing that I regret, I've learned a lot for very little investment, so for that reason alone its a success, and with all the seedlings coming out of it already, its a double success

 

Wonderful post Clueless, I can feel your intense committment and it is making me smile,
thank you,
Jenny