Lighting up time: a gardener’s guide to the new grow lamps – The Guardian
Popping up in living rooms across the country, and certainly as questions in my inbox, is the new generation of grow lights. An amazing tool, these can be a conundrum for many. So here’s a quick guide to cut through the confusion.
First things first. The concept of grow lamps isn’t exactly new. As a way to boost plant growth in areas with poor natural light they have been kicking around since at least the early 1980s. The problem is that, until very recently, they were enormous, incredibly complex to fit, and kicked out so much heat that, ironically, they could often burn the very foliage they were trying to nurture. That’s before we considered their eye-watering cost, not only to buy but to run. We were talking upwards of £200 to buy a single, incredibly energy-inefficient bulb.
About 10 years ago a new generation of LED lights started hitting the market
All this started to change, however, about 10 years ago when a new generation of LED lights started hitting the market. Using a fraction of the energy and emitting very little heat, these products have been steadily decreasing in both size and price over the years. You can now buy bulbs that will fit any standard desk lamp for little more than the price of regular ones. Even flexible LED strips can be taped into place to line the underside of bookshelves, cabinets and larger terrariums.
As pretty much all houseplants need to be grown within 2m of a window, these lamps dramatically open up new opportunities for indoor growers – and even for regular gardeners who grow many tender or half-hardy species from seed each year, such as tomatoes. Without a greenhouse, grow lamps are really the only way to get significant quantities of seedlings away at this time of year.
This sudden boom has meant there are now so many options available in different shapes, forms and colours, it can be a little bewildering. As a basic rule, the most important thing to remember is that plants will grow in really any light that humans can see. However, they do have preferred spectra, which mainly look blue or red to our eyes.
That’s why many grow lamps have crazy disco hues to them, with many even having adjustable functions to change their colour. This is because changing the wavelengths of light that plants experience can, amazingly, change their behaviour. For example, upping certain wavelengths of UV can make cannabis kick out more resins, or infrared can cause commercial tomato crops to fruit more.
However, are these really relevant to home growers who just want plants to look good? No. Can you even see a plant’s true colours under coloured lights? Nope. Do they fit in with most people’s idea of what they want their living room to look like? Probably not. So, I would always side-step these in favour of the simplest options that emit white light. Frankly, even regular daylight bulbs will work fine.
So please don’t feel confused, just pick the options that fit your budget and …….