Hacker News Reader

has anyone compared energy using LED used in growing plants? sure sun is free but in winter conditions or at night for example? would it be more cost effective to keep plants in the sun during the day and give artificial light at night so that they keep growing 24x7?

View on HN

Most plants need a dark period in order to grow well. You don't actually want 24x7.

A lot of northerly greenhouses use sun + supplemental lighting to keep the day length long for maximum growth, however, while not paying to keep the lights on all day.

Many years ago I saw supplemental light used in commercial hothouses to extend the day. (~49°N)

When the sun was setting, they came on and gave a few more hours of light.

There's also the bonus of waste heat.

Reply on news.ycombinator.com