Lighting for polytunnel

Hi everyone anyone got any ideas about lighting in a polytunnel to extend growing season ? or am I just being over-enthusiastic (hope I spelled it right) My wife saw something on countryfile but didnt take a lot of notice Thanks Mick

 

Madmick - it can be done, but wouldn't be practical. I grow some plants under lights in both a special light-box and also in my house.

The key thing about light is the light level. Because our eyes adapt automatically, we are not very good at judging light levels. So I have a light meter. On a sunny day in summer the level can be 25,000 lux (a measure of light intensity). Inside your sitting room at night with the lights on, the level might typically be 50 lux. Now thats is a big difference. In a brightly lit office it might be 500 lux.

Sources quote the minimum for any reasonable growth is 3,000 lux. What that means is that you would need 6 times as many fluorescent lights in your polytunnel as you would find in a brightly lit office.


I have a light box, shown above, where I can get plants to grow and flower. The light level at the top of the plants is 10,000 lux, and to get this level I use 3 three foot long fluorescent tubes over a growbag tray. I also have to have the lights very close to the plants as light levels fall away with distance and I also enclose it in a white box with doors at the front to stop any light escaping.

It costs about £6 a month to run and I keep it in the house to make use of the heat. On that scale it is quite practical and great fun. I have germinated summer flowering plant seeds in November and had them in flower by early January. Its especially good for raising early plants from seed and for taking cuttings over winter. As I said it could be done on the scale of a polytunnel it would be very expensive. :D

 

I saw this on another forum a while back .... not sure if it works as stated, but found it interesting ...

LED Grow lights perfect for indoor gardens. DIY - YouTube

 

Dim - interesting video. LED lights are potentially excellent as grow lights - but they are very expensive to buy. The lights shown cost 60$ for 13 watts. Now they may give out twice as much light per watt of power as fluorescent tubes, but they can cost up to 5 to 10 times as much to buy.

As I said on another thread about grow lights, there are many ways of delivering the right amount of the right type of light, but eventually it comes down to which is the cheapest way.

 

How about getting a load of those little LED pushlights from the £1 shop - you get three in a pack. Take the back off, wire them all up in series, attatch to a length of wood about 1" wide and attatch this to the underside of a piece of guttering. Wire up to a switch connected to a battery. Maybe connect to a light sensitive switch so that it comes on as soon as sun sets. Either use two batteries - one to charge while the other is in use or wire up a couple of cheapy solar panels (Maplin £12) about 2 watts at 12 volts.

How about using an old paygo mobile phone, put a light sensitive switch against the screen and encase it in a box so if you call that mobile the screen lights up switching on your growlights, watering system or maybe a cctv camera?

 

Wow Richard I think you need to get out a bit more

 

1thing IMO that makes growing your own food so enjoyable is eating what you can fresh whilst in season,it is not really worth trying to simulate nature it can be done and is regularly by the growers in professional systems and people growing certain crops that sell by the gramme

 

That put an amusing scenario into my head, setting up a hydroponics system in the attic & waiting for plod to detect it with their thermal cameras.

Imagine how embarrased they would be when they busted your Tomato farm

 

truth is stranger than fiction ziggy
Police raid 79-year-old woman for pot, find tomato plants - Boing Boing

 

I did get asked by my neighbour if the Tomato in the kitchen was a pot plant.

I have a friend who planted a real pot plant in the flower bed at the front of Sherbourne police station. It was there all summer Police walking past it everyday