Geopod

Thanks for that Scrungee
So, let’s say I wanted to construct one measuring (say) 1m x 500mm, how many lights do you think I’d need? Two?

 

I use two x 600 x 400 x four flourescent tubesT5 Lightwave lights in my greenhouse growbox, and without going down there to check the overall area they cover, I'd guess about 4.8m (2 x 4 x 0.6m) run of tube for 800 x 1100mm, approx 0.88m2, so very crudely assuming LED tubes have same output as flourescent tubes, pro-rata that would be 5.45m of tube per square metre,.

So 1 x 0.5m, 0.5m2, might require 2.73m total length of tube, which would be 4.55 x 600mm tubes, and probably 4 tubes dependent on checking output compared to fluorescant tubes, and intended height above plants, the latter might be significant with cool LEDs and they should be able to be lowered closer and provide more illumination.

 

NB Since I posted the link to 4 x 600mm LED lights for £16.95 several minutes ago, they have sold out.

The comparison I wanted to post was to 4 x 600mm T5 fitting costing £69.99 and costing many times as much in running costs. Maxibright Lightwave T5 2ft 4 Tube Propagation Grow Light Hydroponics | eBay

 

I got a vitopod propagator for Christmas, which is made by the same people as the geopod I think. I really like the propagotor itself - it fits seed trays in neatly without wasting space, and is a nice sturdy build, I can see it lasting me a long time (as it should for the price!) - but the lighting unit has been disappointing so far. Flimsy in comparison to the rest of the unit, and makes access awkward. If/when I need more growing space I'll go down the DIY route as originally planned.

 

After a good night's sleep (whitefly bait?), and inspired by the Geopod design, I decided to use my 4 LED tubes to make a growbox top to sit on top of my Sankey propagators, sides consisting of 2 'stacking' sections so I can vary the height by either using 1 or 2 of them, 4 tubes on the lid which will lift off (so could be moved onto another propagator or even a plain unheated base, wired up so either 2 or 4 tubes could be used.

Just need to have a think about pacticalities of access, especially watering. I''ve sown some mini bush tomatoes and onions to use in a trial.

P.S. As soon as I get my lights I'll compare light meter readings to my other growlights.

 

Hiya @Scrungee .
I like the stacking idea.
Been having a think () and I’ve come to the conclusion that I might as well make use of the lighting I already have. I hadn’t really considered making a grow/light box. So, I’m thinking the box will be constructed of 1/8th ply or some such, with a drop-front to allow access. The lighting (with canopy) can sit on the top. I haven’t as yet measured the canopy, but I can if necessary just fill in around, leaving a small gap to allow for ventilation. I’m thinking that the box will measure around 1m x 500mm, depending on the size of a suitable heat mat.
A couple of questions. How high above the base should the lighting be? I was thinking around 12”? Regarding the heat mat, which one to go for? I’d want a good one, reliable and effective. Btw, I wouldn’t want to use eBay for this.
Cheers

 

I had to do a bit of tracking down the source of my thermostatic mat bought over a year ago, and it's one produced by Kirklees Developments ( better known perhaps for making 'Fir Tree' greenhouse gas heaters) Propagation Mats or Panels, Propagation Mats, propagation_mats N.B. The wattages are for the cable used, regardless of the mat size, so it needs to be divided by the area to compare different size mats.Use the price with VAT added then add £11.99 for delivery.

But I didn't buy from them, I got mine (larger, cheaper per m2, now sold out) from Propagation Heat Mats UK because they were selling them at allmost half the cost of getting direct from the manufacturer, but they now appear to be sold out of many sizes (not surprised). They only have 2 left, one each of the following sizes, and they appear expensive per m2 compared to the large size I bought, caused by spreading the cost of the thermostat over a small mat):

0.40 x 0.75m £75.99, 65w, 0.30m2, 217w/m2, £253/m2 (£146.99 from Kirklees)

0.60 x 0.75m £109.24, 67w, 0.45m2, 149w/m2 £243/m2 (£146.99 from Kirklees)


I haven't been looking at heated propagation muc (at all?) in the last year, as with the 7 propagators and mat on the staging down one side of the greenhouse I've run out of room to cram any more in.

 

Thanks for that
If you wouldn’t mind, could you take a look at this?
Propagation Heating Mats with variable heat control at Suttons Seeds
The Sutton’s one is slightly cheaper, but they do differ. I’m looking at the 1.2m x 600mm models. Note the probe with the Suttons model, and the different wattage.

 

I should have said, I was comparing the Suttons one to the one in your first link, just in case there was any confusion.

 

@Scrungee , could you have a look please?

 

Have a look at Heat Mats, Cables & Thermostats at Jungle Seeds.

The problems I'm now finding with heat mats are that it appears to be difficult sourcing a 'propagator sized' mat with a comparable wattage suitable for germinating seeds requiring higher temperatures, and opting for a larger size mat to get better value for money means using the same temperature setting for whatever's in it.

Which is why I continue to snap up those Sankey propagators mentioned above for as little as £10 each from ebay, but that's with collection only, as they go for much more with a delivery option.

 

Thanks again
They seem quite reasonable, compared with the other two I was looking at. As I said, I would be using it primarily for Tomatoes and Chillis, so shouldn’t pose any problems regarding temperature? I always have the option of using the propagator in the greenhouse

 

Ok, so I’ve ordered the 40cm x 75cm heat mat. I checked my lighting canopy which measures around 72cm long, so the size I’ve ordered seems appropriate.
@Scrungee , how high above the base should I have the lighting? I thought maybe 12-15”?

 

Do you have:

1) A light meter?
2) The wattage of your lighting?

I've tried calculating the wattage/m2 of my 2 different grow light systems, taking light meter readings, then comparing the 2 using Inverse Square Law of Light calculations, and can't make any sense of the results, the formula only works for me using the same light source at different heights, and using diferent arangements of differing wattage/length/spacing tubes isn't that simple to adjust.

My indoor growlight has 8 x 54w tubes over an area of 600 x 1120mm, the underside of lighting is 460mm above the base of the box (NB below top of pot/foliage levels) and with all 8 tubes on (I can select all or alternate tubes) my light meter reading is 17,000 LUX at base level (111,000 LUX is bright sunlight Daylight - Wikipedia ). It is very bright in that box!

My 2 greenhouse growlights have a total of 8 x 24w tubes, for one growlight the tubes are over an area of 500 x 250mm, the underside of lighting is 350mm above the base of the box (NB below top of pot/foliage levels) and my light meter reading beneath the one light I turned on was 11,450 LUX at base level, which seems about right to me.


So "maybe 12-15” ( 305 to 380mm) is about right, depending on what lights you have.

If you don't have a light meter, there are free 'light meter" apps available to download, but I think there's criticism about their accuracy, although calibration can be checked against either a camera's settings on manual pointed at white card/paper, or the EXIF data from taking a pic of it.