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Grow lights

Boosting light levels early in the season

Grow light in the conservatory over sweet peas, tomatoes and Echiums
Grow light in the conservatory over sweet peas, tomatoes, and Echiums

No, it’s not Studio 54, it’s my conservatory in February.

I stepped into unknown territory this year, using a grow light for my seedlings. I’d been toying with the idea for a few years – even though the conservatory has good light, a few extra hours a day or to boost dull days would be a real help.

And it did prove handy – plants were further on, especially sweet peas and tomatoes – unfortunately, we also had a cold April which led to a logjam in the conservatory and greenhouse. Well, you can’t have everything.

It also meant I could stagger my sowings even earlier – I bought four different types of Echiums, which ended up taking up a lot of room.

“We’ll be having a visit from the drugs squad,” moaned the other half.

Three blue and nine red bulbs
Three blue and nine red bulbs

It also means there’s less chance of legginess with early seeds, like half-hardy annuals, tomatoes, and sweet peas.

Grow lights can be used to supplement natural light if there’s not enough sun; as the sole source of lighting, or during propagation.

It’s important to note this is not an ordinary light bulb – there are red, blue and orange-red elements. The red and blue parts of the spectrum are for compact foliage growth, while orange-red simulates noontime sun and encourages flowering. As I want sturdy plants, my bulb is red and blue.

My bulb was under £16 (LED Plant Grow Light, THZY 12W, E27, 3 Bands) and it fits into a desk lamp with an E27 fitting. I bought a tall one with a clamp fitting for £15 – both bulb and lamp came from Amazon. This means you don’t have to invest in a permanent fixture and it’s moveable.

Obviously, make sure there’s a plug nearby – but out of the way of any potential water spillages.

I used a basic light timer, giving the plants 12 hours of daylight, until the end of March.

This can be increased to about 16 hours, but plants also require at least eight hours of darkness each day.

For seedlings/cuttings, the light source needs to be placed as close as possible to the plants.


Potted guide: grow lightspotted-guide-logo

  • NAME & PRICE: LED Plant Grow Light, THZY 12W LED Plant Grow Light For Hydroponic Garden Greenhouse (E27, 3 Bands) – £15.65
  • BULBS: 12 LEDs (3 blue & 9 red).
  • FEATURES: Low power consumption, does not generate noticeable heat.
  • TECHY STUFF: Emits the wavelengths of light which can be fully absorbed by plants; 660 and 430nm; 630 and 460nm, four peaks of growth spectrum for maximum chlorophyll A and B production. Rich in red light for blooming and fruit and blue for promoting leaf growth.
  • OTHER EQUIPMENT: Fits standard E27 socket, a desk lamp will do.