How to make your orchids rebloom?

If you love orchids and would like them to rebloom again in your house, this article is for you.

by Jille Kuipers

How often do store bought orchids bloom?

A typical store-bought orchid bloom once a year, with many flowers along the flower spike. Blooms may last several months. Eventually, the flowers will wither and drop, leaving a bare flower stem. Many people discard the orchid after it has stopped flowering. But orchids are capable of reblooming again after a period of rest. During this period the orchid can store nutrients and water in the leaves, so they can feed the orchid flowers when it is required.

How can I get my orchid to bloom?

The most important factor is sufficient lighting. Other factors that can influence an orchid’s ability to rebloom are for example a cooler temperature at night and fertilizer. However, most people overlook the importance of light. If you observe that your plant has less flowers over time, it is possible that the light is insufficient. Orchids that you buy in the store were propagated in a greenhouse with 100 to 300 micromoles (amount of light that plants can receive). In a greenhouse they most likely control the growth environment (including lighting), so they can grow orchids all year round and manage the flowering time. And at a windowsill in your home, you might get maybe 20 micromoles, especially during the winter season.

On the left an orchid with flowering buds and sufficient light exposure. On the right one with less light and no flowering buds. Photo credits to the American Orchid Society

The most important factor is sufficient lighting.

How can I see if my orchid receives sufficient light to rebloom again?

The amount of light varies per orchid variety. But as a general rule of thumb the leaves should be a light green rather than dark green. The leaves of the plants should be firm and stand upright. Plants that have very long sloppy leaves are grown under insufficient light and stretch themselves to find more light. If the light level is lower, the plant leaves have to be bigger to get to the same amount of light, but bigger leaves makes them more sloppy and the leaves won’t be firm and upright.

Nice bright green leaves are an indication that the orchid receives sufficient light

Does a general spot light create sufficient light for orchids?

General spot lights are designed to provide light that is visible to the human eye. White light for the human eye contains generally a large amount of green, with a much lower amount of red and blue. These colours together are perceived as white light by the human eye. However plants perceive light differently. The human eye is most sensitive to light in the green area, whereas plants are most sensitive to light in the red and blue areas. Different colours of the light can support different plant hormones and processes. For example for flowering the amount of red is very important. For the growth, the amount of blue is very important. It is therefore recommended to use grow lights that are designed for plants.

My windows are coated, will my orchids receive enough light?

A glass coating can alter the spectral quality of the light. It is important the orchids receive enough red, blue and a bit of green.

My window receives a lot of light, can I rebloom my orchids without a growlight?

If you have south-facing windows (northern hemisphere) you might get sufficient light. Watch your plants to see if they indeed develop flowering buds and if the leaves are light green. However, it also depends on the actual brightness of the natural daylight. E.g., in Northern Europe the days can be very short during wintertime and the amount of natural daylight quite week. Your orchid needs at least 8 to 12 hours of access to good bright daylight.

Are my orchids receiving too much light?

Orchids naturally grow in tropical areas and thrive on trees and other vertical structures. It means that they have some shade and the amount of light that they receive is less than plants that grow in the open. Orchids prefer something around 100 to 150 micromoles, which is about half of, for example, a tomato plant prefers. Orchids should therefore not be placed in direct sunlight as they might get hot and sunburn. They should also not be placed under grow lights that are too powerful or designed for high-wire crops.

What grow-light would you recommend?

Well-designed grow lights such as the Bloomer 2 and Nurser 3 emit the right spectrum for orchids and have an appropriate intensity. Bloomer 2 can be used in desk-lamps or any fixture that enables screw-in lamps (E27). The Nurser 3 can be mounted in a greenhouse cabinet or rack at home and is available in different lengths to fit in your space.

An example of a yellow orchid with flowering buds that were stimulated by the Bloomer 2 grow light.

Grow lights that contain only red and blue emit purple light, which could be a bit unpleasant in a decorative setting. The color of a Bloomer 2 and Nurser 3 growlight is white with a pinkish color tone. The human eye will primarily see white with a pinkish color tone and it enables you to see the plants well. The plants will primarily receive red, blue and a bit of green. It is therefore an excellent light effect for an indoor grow light.