Mmmm new Project – DIY Light Grow Box…

So….. I was sitting at the Christmas dinner table (on boxing day) with the family and suddenly decided I need a grow box to play with for growing some show onions, a few peppers and chillies. As these need a warm place to have a kick start in life. I like to sow my chillies and tomatoes early in the end of January, and some tomato seeds later again in March and these tomatoes will be grown outside later in the summer.

I had a light box of sorts sitting in my garage for layering my vinyl signs which I had made out of an old cupboard from a skip with some lights inside and a perspex top. Basically a box to lay signs on and then lay another one on top in the correct positions to create different backgrounds etc. I don’t use it any more so decided it can be DIY’d into my new grow box.


I removed the lights and door, hacked it shorter and started on the new design. I had previously used 6 energy saver bulbs and had some plugs and switches in my draws.

I decided on using 2 bulbs and have them adjustable so I could follow the growth from small to quite tall as the box was now just under a meter tall!! So I got stuck in and made the light carrier bar to be adjustable and also decided it may need some air circulation so I dug out some old PC fans that I collect from dead computers. The box had holes top and bottom for convection airflow as well. There would be no need for separate heating as the bulbs would get hot and heat up the air inside. I also purchased a temperature controlled plug unit to control the cooling/circulation fan. The whole inside of the box is lined with aluminium foil to reflect light and the two bulbs have a reflector to reflect light downwards as well. It also has a “Peek a Boo” flap to look inside without letting precious heat out. To run the fan I found an old mains adaptor like you get on Christmas tree lights or phone chargers and the fan will run on about 6-12 volts so most old adaptors will be fine. I have a few spare that I collected over the years so any breakdowns can be sorted asap.

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 I put everything together and it really looked good. Then I was Googling about grow-lamps and realized that the bulbs I had were not the right light spectrum for growing purposes so I had to buy others to suit. I went for CFL type helical design (compact fluorescent lamp). The bulbs are 30W but are equivalent to 150W  incandescent light in old terms and only cost under £3 a month to run 24 hours a day.

I made a pile of seedling supports with kebab sticks and copper wire to use what they start to grow and need supporting. It all really turned out well but it was soon full with only a handful of seedlings put inside!!

Oh well – back to the drawing board….. and re-make it as a bigger but not as high unit. Really just turn it on it’s side.. and make a new light carrier, move some of the electrics, move the perspex door…. etc.


I stripped it out and started again. Now that it will be longer I need another bulb – luckily I bought 5 and I had a few spare light fittings. The light carrier is now also stronger and simply gets screwed in place to the height as required.  Put the new design together and all looks great. I still need to foil the light carrier bar and find a big reflector as the original one I made is now too small with the added extra bulb.  (It is also longer and I can place my chitting potatoes on top as it is placed where I normally do the chitting).


The temp controller clicks in the fan at 21 degrees C and runs for a few minutes every now and again. This brings in cold air and blows it in from the top and will circulate the air at the same time. I have covered (with aluminium foil) most of the previous holes with I had cut out for convection airflow and  left two each side. I can easily just punch the foil to open more if the temp remains too high and have more PC fans to add if required. My plan is to start some show onions, chilies and peppers off in the propagators then move them into the light box after they have started to grow. About 6 weeks with 24 hours a day light then down to 12-16 a day. I dont know how long they will stay in this box due to the height. I have a problem of when the seedlings out-grow the box height!!! Maybe have to sneak them into the conservatory without my wife noticing…. bit difficult!!

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 Notice the new smoke alarm I fitted above it – just in case!!


Gavin Conway
Moved to the UK from Zimbabwe in 2001. We had a 12 acre plot with a 2 acre normal garden, loads of Koi ponds, a 2 acre veg garden, 3 orchid sheds with over 400 plants, bonsai shed, granny cottage and workshop area.. Comming to the UK and into a 3 bed semi was a shock!! But we knew what to expect and just got on with our lives. I love growing veg and started to grow on my flat garage roof for a few years then moved on to a couple of garden shares then onto a full sized allotment at the end of 2011. I have done loads of work with it and got it looking good. see my blog site at Hope I can help others with info on growing and getting ground and allotments to their liking. Self employed with Kleeneze Gavins grafix doing vinyl signs and a personal courier with Yodel..

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