How to use artificial lights in the home
Plants absorb mostly blue and red light (think of the colours present in a rainbow, plants use two particularly) in order to grow and flower. Blue light generally stimulates growth, while red light is important for growth and flower production.
T5 HO tubes are available that produce colour values based on the Kelvin scale (K). Tubes with a 4000K value tend to produce light with a reddish tone, while those with a value of 7500K produce bluish light. If using fluorescent tubes to grow flowering plants, a combination of red and blue tubes will provide the best light for growth and flowering.
Having the lights on for a sufficient number of hours is also an important factor – see the guidelines below for each set up.
Simple lighting system
There are a variety of kits available which include an electronic ballast (that starts up the tubes) and reflectors to direct the light downwards onto the plants.
- In the home a basic set-up could be a unit containing two 60cm (2ft) T5 HO fluorescent tubes suspended approximately 60cm above for example, a small group of houseplants, or crops such as leaf salads for fresh leaves during the winter months
- The lights can be on for around 16 hours a day
- Plants often require different light intensities. The foliage colour is a good indicator to determine whether the plants are receiving enough light and the intensity can be adjusted to suit them (See: 'Problems' below)
These benefit from predominantly blue light to promote good growth and compact plants. The T5 HO tubes should be placed around 60cm (2ft) above the seedlings for around 16 hours a day.
Tomatoes for example can be started earlier in the year under lights when natural daylight is still too weak. This enables plants to be more advanced by the time they are planted in their final positions in the greenhouse or border. Again adjustments can be made regarding light intensity requirements. (See: 'Problems' below)
Phalaenopsis (moth orchids) and African violets (Streptocarpus syn Saintpaulia) can be grown under lighting very successfully and are tolerant of a variety of lighting conditions. Leaves should be a mid-green.
Plants from naturally low-light habitats, such as ferns and many of the smaller tropical foliage houseplants that in nature inhabit shady forest floors, can be kept healthy long-term under simple artificial lighting. Use an aquarium tank as a terrarium for these plants and position the T5 HO lights in the hood. Not only will this provide a decorative focus in a room but the terrarium will help retain the high humidity which these plants love.
Other plant genera
Different plants will vary in their lighting requirements to grow and flower well. It is best to research the light requirements of your chosen plants and ensure the output of the lighting system is sufficient to ensure success. This can be done by carefully measuring the intensity and quality of light provided using a quantum light meter.