Why is our night sky turning purple?
DOZENS of readers have been contacting us asking why they can see a purple glow in the night sky every evening.
Lots of you have sent us photos of the strange phenomenon, from places such as Southport, Scarisbrick and Ormskirk.
Malcolm Herbert said: “Driving home to St Helens at 10.30pm, we observed a spectacular purple / red sky in the general direction of Birkdale and Ainsdale. It lasted for about 10 minutes before the rain clouds obscured it from our view.
“We understand from previous sightings that the cause is unusually high pressure.”
Samantha Rose said: “I have been seeing the same light in the same place on and off for a couple of months.
“I thought it was far too luminous to be aurora borealis. I tweeted the council about it, but they didn’t respond.”
But now the reason behind the purple/pink light can be revealed.
It all comes down to tomatoes.
Tomato grower Flavourfresh Salads, in Scarisbrick, has for the past year been using LED lights to help aid the growth of its award-winning tomatoes.
The lights, which are a mixture of blue and red, are used in the greenhouses and when combined appear bright purple.
When switched on, they can be seen for miles with people claiming to have seen the purple or pink colour in the sky from Southport, Formby, Ormskirk and Liverpool.
However, although the lights are turned on every night there will only be certain times people will actually be able to see the sky change colour from a distance.
Andy Liggat, nursery manager at Flavourfresh, said: “The reason you get the beautiful coloured sky is because of the weather.
“If you get a nice clear night you won’t see it but if it is misty, raining or foggy the LED lights will shine on the cloud and that is what gives it that glow.
“If you woke up at 5am and it was a nice clear morning you may see a tint of it but if you woke up to fog and looked, you would be like ‘wow’.”
The lights were installed by Tarleton-based Eco Electrical & Building Services.
Inside the six-and-a-half acre site there are 100,000 plants producing 420 tonnes of tomatoes a year.
The huge greenhouses have blackout screens on their windows, which are computerised to close at night which is when the LED lights come on.
There are gaps of about a foot left in the blackout screens meaning that the lights can shine through and up into the sky.
But there is a reason why people may see a glowing skyline more often in the coming months.
Andy explained: “The LED lights elongate the daylight in the greenhouses for the tomatoes. So as the nights get darker earlier we turn the lights on earlier. We are basically giving the tomatoes 18 hours of daylight and kidding them, in effect, to thinking it is daylight.”
The company, which produces the speciality crop for Asda and M&S, has been in operation since the mid 1970s and was the fifth in the country to trial LED lights.
In the greenhouses, which average at about 24°C (75°F), there are about 3,000 LED lights which have replaced the previous high-pressure sodium lights.
Andy said that the change to the LED lighting was in keeping with the demands from the public and supermarkets.
He said: “If you don’t have light, you can’t grow tomatoes.
“In winter you don’t have the necessary sunlight so the LED lights make it possible to grow the tomatoes all year round.”
Flavourfresh, which has 11 full-time staff and 25 seasonal staff, produces its electricity on site and has a reservoir at the back of the site for water.
There are also a number of hives in the greenhouses for the bees that pollinate the tomatoes and biocontrollers are used to rid the plants of harmful insects – rather than the use of chemicals on the plants.
Andy said there have been no negative comments about the colourful night sky and he has invited neighbours close to the factory to look around.
He said: “I am used to it now but I agree that it is quite a stunning sight to see in the sky.
“People are quite surprised when they come in and see what it is like here.
“We see so many comments about what the pink in the sky is – some thinking it is chemicals, but it isn’t.
“Only 20% of tomatoes in stores are British, the rest are imported so what we are actually doing here, with the lights and how we operate is keeping people in jobs – and it means less has to be imported.”
Here’s the answer! Clockwise from left: The Flavourfresh Salads greenhouse in Scarisbrick; Horizontal LED strip lights among the tomatoes; A staff member with the tomato plants; The plants at night with the LEDs on; The light reflected across the night sky by low cloud