For peat's sake: Alternative growing media

Sep 04, 2009
These are colorful camellias which were used in the study. Credit: Photo by Federica Larcher

Peat, or semi-decayed vegetation matter, has been used by commercial growers and amateur gardeners since the middle of the 20th century. Peat is added to potting soil to help retain moisture and provide additional nutrients. As the demand for peat grew, acres of peat bogs were being drained and destroyed. Now, concerns about the environmental impact of extracting peat from wetlands are mounting. And as peat supplies are reduced, the cost naturally increases. Diminishing supplies and environmental and economical concerns are encouraging researchers to find viable alternatives to this popular growing medium.

A recent research study led by Federica Larcher and Valentina Scariot of the University of Turin's Department of Agronomy evaluated five materials as partial peat substitutes. The results, published in HortScience, show these alternatives have potential.

The study focused on growing camellia, a woody plant that prefers acidic soils and is often grown in containers for decorative purposes. Three varieties of camellia ('Charles Cobb's', 'Nuccio's Pearl', and 'Dr. Burnside' ) were tested using a combination of peat and the following peat alternatives: green such as grass clippings and leaves, pumice, coconut husks broken down into fibers, composted coconut "peat", and pine bark. Each variety was also grown using the standard commercial Sphagnum peat as a control.

Plant growth and the ornamental quality of each plant was evaluated during each phase of cultivation, potting, before repotting, before and after branching and at the end of the experiment. "The alternative growing media tested…performed as well or better than the standard substrate," the study reports. However, green compost was the exception. Plants grown in green compost had the lowest evaluations in all categories. Green compost also increased pH levels with negative effects on plants.

The impact of the different growing media seemed to be most notable during the first 2 months. After that time, no relevant differences were noticed. "Overall, coconut fibers and pine bark resulted in being the most suitable partial peat substitutes," stated Larcher, adding that none of the plants grown in any mixture showed signs of malnutrition or toxicity at any point during the study.

Coconut fibers are recommended as the best option considering technical and economic factors. The study recommends that adjusting fertilization and irrigation practices to make the most of coconut fiber and peat mixtures will help reduce the costs and losses for nurseries.

More information: The complete study and abstract are available on the ASHS Hortscience electronic journal web site: hortsci.ashspublications.org/c… nt/abstract/44/2/312

Source: American Society for Horticultural Science

Explore further: Bad reputation of crows demystified

add to favorites email to friend print save as pdf

Related Stories

Peatlands disappearance of concern

Nov 10, 2006

A report released Friday at a U.N. conference in Kenya indicates clearing peat lands threatens the world's ability to reduce carbon dioxide in the atmosphere.

Nitrogen rain makes bogs contribute to climate change

Dec 11, 2006

High levels of nitrogenous compounds can make bogs give off more carbon dioxide, thereby adding to the greenhouse effect. This has been shown by the plant ecologist Hakan Rydin in an article published this week in the Proceedings of ...

Substrate developed from sawmill shavings

Mar 07, 2006

University of Navarre scientists in Spain have developed an organic substrate from sawmill wood shavings to use for intensive crop growth in containers.

Recommended for you

Bad reputation of crows demystified

Jan 23, 2015

In literature, crows and ravens arebad omens and are associated with witches. Most people believe they steal, eat other birds' eggs and reduce the populations of other birds. But a new study, which has brought ...

How gerbils orient in the light of the setting sun

Jan 23, 2015

A light brown remains light brown: For gerbils, the fur color of their conspecifics appears identical under different lighting conditions. The ability of color constancy in rodents has been demonstrated for ...

Snack attack: Bears munch on ants and help plants grow

Jan 22, 2015

Tiny ants may seem like an odd food source for black bears, but the protein-packed bugs are a major part of some bears' diets and a crucial part of the food web that not only affects other bugs, but plants too.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.