Growlights: Building the Perfect Grow-Box

We,ll have two ... each ... then, eh?!!

Missed that when I bought my 60cm square rig. Something to get as an extension a bit later on ... ah, now I remember, it was collection only ... and now I see 3CHhave opened a new store not that far away

You need to put the PC you use for this forum in there too ... all the extra Hot Air will be a benefit too

Useful points Gonzo. Many thanks

 

The 'beast'. It has 2 switches, one that operates the 4 middle tubes and the other operates the 4 outer (2 each side) tubes to reduce electricity consumption if only part of the area underneath is being used.



Now I've physically measured the overall dimensions at 665 x 1118mm, I reckon on fitting 170 nr 70mm square pots underneath (10 x 7), so with say 4 different batches of plant, with an average of 2 changeovers/day and costed over 3 years (I don't know when the costs of replacement tubes will kick in), that would only be 3p per plant (excluding electricty costs, and I have Economy 7) which seems reasonable to me (and I'm extremely tight with my cash).

 

Me too!

As I've got loads of Amazon vouchers I was thinking about this one:

http://www.amazon.co.uk/Sinometer-D...TF8&colid=1CVRB2TYJJZQW&coliid=I1V1PDMV292QIB

 

I've got this one (which appears to be cheaper on Amazon than it was on eBay :( )

http://www.amazon.co.uk/HDE-HDE®-Digital-Light-Meter/dp/B004VRHJTS/ref=pd_sim_sbs_ce_5

 

+ £6.50 for p&p Kristen

 

Sorry, must have been asleep on the job! In that case:

eBay £11.97 and free postage
http://www.ebay.co.uk/itm/270804604426?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

No guarantee that it is a good model though - although a friend on another forum, who has one, put me on to it

 

I think the one I've ordered has a much more snazzy liverey.

But it might be useful to compare readings from different units using various bits of kit including the one I'ved ordered. http://www.amazon.co.uk/Sinometer-D...TF8&colid=1CVRB2TYJJZQW&coliid=I1V1PDMV292QIB

 

Thank you Kristen- just bought one,
Jenny

 

OMG What have I started? !!

 

They've now sold 140. Only 10+ left,
Jenny

 

My own light meter looks similar, with a digital display and three scale settings - and I have been very pleased with it. Previously I bought a meter, in a garden centre, with a probe that doubled as a pH meter and a light meter. It was cheap but absolute rubbish. It kept telling me that a 40 watt incandescent bulb was giving out more light that 90 watts of fluorescent tube.

I am always a bit wary of multipurpose tools, and prefer one that is made to do just one job.

 

I particularly wanted a light meter to check out the effect of placing my 2 smaller lights vertically around the new, larger light.

Something I don't think has been mentioned yet as a requirement for the 'perfect grow box' is being able to start with a small area of lighting for germinating seedlings and gradually increasing the amount of lighting each time they are transplanted into larger pots, including using 'shifts' to maximise use.

Earlier this year I got all enthusiastic about getting loads of seeds sown in both trays and pots under my first light and rapidly found I needed a 2nd light and to rotate plants around up to 3x a day under each. For example if 16 chilli seeds were in a single 70mm square pot (actually 68 x 68mm) and then they were then transplanted in 40x modular cell trays (each cell 43 x 43mm), the area required suddenly increased by 640% and if each plant was then potted up in 16 individual 70mm square pots that would obviously be 16x or 1,600% more than originally.

Changing everything inside up to three times a day helped a lot, but what made things worse was the awful cold and lack of light that meant stuff couldn't go into an unheated polytunnel and my heated greenhouse was crammed full of plants all needing a boost under the lights.

So what I'm taking a long time to get around to is that it might be a good idea to have something like one small light plus one (or more) seperate, possibly larger lights that will come into use when the seedlings from under the smaller one can no longer be accomodated, even using 2 or 3 'shifts' per day.

 

I wonder?? if Metal Halide would be the answer for the growing-on "over spill"?

Covers a large area, 1/4 to 1/3rd price per sq.m., probably does a "reasonable" job if you lift it up - further from plants, covering larger area - if we have a rubbish Spring and you are faced with having to try to artificially light twice as many plants as you would in a "normal" Spring.

I had my MH lamp in flimsy polytunnel "blowaway", which was itself inside conservatory, and it was a good distance above the plants. I thought it wasn't doing much good, but I did compare photos of Coleus with a chum and although they started off the same mine were definitely much further ahead a month later - even though still, to my eye, rather small. With a better Spring I would probably not have needed the light, and both of us would have had better looking plants.

Also worth considering, in a greenhouse/conservatory setting, is that MH does not provide much shadow from the Sun (unit and reflector only covers small part of the lit area - unlike a fluorescent tube lighting rig), so daytime sunlight can still easily reach the plants. I ran mine overnight (Economy-7), plus it contributed additional heat during cold spring nights. Might be enough to do one-batch-one-night and another batch on a second night - thus supplementing daylight by "a bit"?

 

Metal Halide lighting will be one of my projects for late 2013 (my next Xmas present), once I've finally worked out how to build a multi-storey grow light box that will probably be 1.2 x 0.7m with my new single light above and 3 smaller lights below (only one more to acquire).

Setups like that costing over £300 just for the lighting units + grow box costs may sound ridiculously expensive - you can get a decent sized greenhouse for that - but for example if you're into sea fishing you can spend that amount on a rod, the same again on a reel, plus fuel & bait costs and still not catch anything enough to recoup costs.

 

An experiment the other day to test the temperature of my windowsill heated propagator (no thermostat) alerted me to the fact that although the room is 20C, and the heated propagator based 28C, the brickwork in the window reveal was only 15-16C ... so considerable heat loss by siteing the propagator in the window-space.

Also, germination needs heat, but once germinated things can be different. My windowsill propagator, with 1/4-size seed trays & transparent perspex lids, are ideal to get seedlings underway, once germinated, but the trays could be in a heated box until then (provided I am eagle-eyed to spot when they germinate, and allowing for some seeds that need light for germination)

So I think my "Perfect Grow Box" should have an a heated section ("Hot Box") for germinating seeds, and starting off Dahlia / Canna / Ginger rhizomes etc - and that Hot Box could be dark.

I've been thinking about reptile heating mats, as they are a lot cheaper than propagators. Downside is that they don't like to get wet, nor have much weight on them, thus important to avoid "point source" weight.

Discussion on another forum suggested polystyrene tiles under the mat (prevent heat escape downwards) then a heat reflector (e.g. survival blanket) then the heated reptile mat; on top of the reptile mat a standard gravel tray which will prevent any wet reaching the heated mat, and also evenly spread the weight of any pots placed in the tray.

My windowsill propagator experience is making me think that the air surrounding the propagator needs to be enclosed, so that the heat is all directed into the trays / pots stood on it (its probably fine for seed trays, not very tall and large ratio of surface area to volume, so capable of absorbing high proportion of the heat from the base, same probably not true of taller pots, and I think they would benefit from an enclosed hot-box)

Perhaps? the idea solution is soil warming cables, however that's a proper bench, several inches of wet sand, considerable weight, and not really conducive to having in the corner of my home office !!. I might have to put it in the (unheated) conservatory, insulate well, and keep the whole shebang out of the house (do you hear the shouts of Hooray! in the background? ).

I might be able to make this into a dual purpose bench for the summer with Mist propagation.

Too long being spent on the Thinking rather than the Doing. No change there then!