Is plant growth affected by container colour?

Does container colour matter when potting plants? If this is something you have wondered about when creating container gardens, you are not alone. It turns out researchers have thought about this too, and they've experimented with different-coloured containers and the impact this factor has on plant growth and health.

Academic studies have proved that planter colours have a measurable impact on plant growth. The direct impact is on soil temperature. Variations in temperature, in turn, impact how the plant grows. Researchers have found that containers in darker colours, especially black, heat the soil more. For instance, in one study researchers grew bush beans in black, white, and silver containers. Soil temperatures on the sunfacing sides of the containers were highest in the black pots and lowest in the white pots. The plants grown in black containers had significantly lower root mass than those grown in the white ones.

Researchers found that the effect was less pronounced in plants that tolerate heat well. Choosing white or light-coloured containers is most important for heat-sensitive plants.

Another study tested a wider range of coloured pots while growing azalea. The researchers found that plants in fibre containers grew the tallest. Those that were grown in white containers grew to the greatest diameter and had the highest dry weight. This indicates that a natural fibre container, or a white pot, is a good choice for maximising plant growth.

While there are different effects of planter colours, these are the most important for nurseries and commercial growers. In a nursery, growers are trying to maximise production for profit, and even small www.gardeningknowhow.com

decisions such as pot colour can make a big difference. As a home gardener, the choice of container colour is less important. For maximum growth, choose white or fibre pots. If you prefer terracotta or other colours, your plants will still grow well. The choice of lighter colours is most important for heat-sensitive plants, especially if put outdoors in hot weather or full sun.