"Show solar energy some love!" That's the call by Greenpeace to South Africa's big five supermarkets to become the superheroes of the campaign to move to renewable energy.Its recent report, Shopping Clean - Retailers and Renewable Energy, ranks the big five (Pick n Pay, Shoprite, Spar, Woolworths and Massmart) on four key criteria: energy transparency, commitment to renewable energy, greenhouse gas mitigation and lobbying for clean renewable energy.Woolworths ranks highest. But with a score of just four out of 10, it is clear Greenpeace believes all could and should be doing more.Greenpeace ranked Shoprite lowest "because of its lack of transparency with regard to the company's energy information".Why pick on the supermarkets? Because Pick n Pay, for example, could liberate enough electricity to supply 65000 households by switching to 100% renewable energy, according to the report. And, collectively, the retailers could free up enough energy to power at least 178400 households.Naturally, how the retailers migrate to solar in their stores and distribution centres - existing and planned - is a key indicator of their "green" commitment.It may not seem that important now that load-shedding is not a constant reminder of the state of our electricity grid, but if consumers started holding retailers to account on this issue, the effect on the grid would be substantial.As with domestic solar water heating installations, there's a significant capital outlay, but it pays for itself over time with reduced spending on electricity bills.But what about the suppliers whose products fill the retailers' shelves? How "green" are they?Well, in the case of the country's largest indoor plant supplier, LVG Plants, very, thanks in part to a prod from Woolworths and its farming for the future programme.The Krugersdorp-based company recently invested R25-million in the southern hemisphere's largest solar water heating facility. The enormous field of solar panels harvests solar energy, which heats a storage tank - housing almost as much water as an Olympic-size swimming pool - and that is then piped into eight greenhouses.That's the equivalent of 14 rugby fields of potted orchids, lavender, roses, lilies and anthuriums, none of which would grow from tiny delicate little things into saleable plants outside of a constant temperature of around 28C.Given that not every day of the year is clear and sunny, even this giant solar set-up can't provide 100% of the greenhouses' heating needs all year round, but based on its performance in the six months since installation, managing director Geert van Geest estimates that over a year it will provide a massive 80% of the required hot water.King of the indoor plant is the Phalaenopsis orchid, commercialised 20 years ago and now the most popular indoor plant worldwide, accounting for up to 30% of all plant revenue.Why so popular? Well, apart from its exquisite beauty, it's hardier than it looks, can cope with being housed in storage facilities and can be manipulated to flower on demand.Woolworths was the first South African retailer to sell this exotic plant in 2007. But there was a problem in the early days - by the time the lovely things had been trucked from Johannesburg to Cape Town or Durban, they would have dropped most of their flowers.So after a lot of trial and error, Woolworths' technologists pioneered a "blocker" that makes the plants immune to the chemical process that causes this "flower drop" in confined spaces. Problem solved.And sales soared.The day I visited the LVG plant last week, the greenhouses were a blush of pink Phalaenopsis, ready to be trucked to supermarkets in time for Mother's Day.As plants go, the Phalaenopsis has impressive green credentials, with just 6% to 8% of wasted water in its production.It takes the same amount of water to produce the entire plant - an 18- to 24-month process from in vitro - as it does to produce a single bunch of cut roses.And once in homes, offices and hotels, the plants require very little water or fertiliser, making them the ultimate low-carbon footprint indulgence.Interestingly, during a recession, sales of potted plants soar. "It's a luxury people can still afford," Van Geest says.MORE PHALAENOPSIS FACTS• Don't assume that if you buy a plant with lots of buds, you'll benefit from flowers for longer: the more open the flowers when you buy the plant, the longer they'll last.• The most common reason for the plant failing to thrive is over-watering.• The ideal temperature range is 18C to 24C. For it to re-flower, it needs to be exposed to temperatures of 15C for up to six weeks at high-light intensity. Which explains why they only flower in Durban in winter.• They flower for between eight and 12 weeks, the white flowers lasting the longest.CONTACT WENDY:E-mail: consumer@knowler.co.zaTwitter: @wendyknowler..