Getting the green light:
Paper pots and solar heating at Ngodwana nursery
Greening the way we grow plants
How it works
The cylindrical containers we use in our nurseries are paper pots composed of non-woven biodegradable paper surrounding composted growing medium. These paper pots are automatically inserted into reusable plastic trays for plant growth in the nursery. Once the plant is established in the paper pot, it can then be planted directly into the plantation soil, where the paper gradually biodegrades.
The benefits
- More balanced and robust root system
- Easier sorting and grading of plants in the nursery
- No plug extraction required = less root damage and faster planting
- Paper biodegrades over time
- Faster pit capture and better survival on harsh sites.
A hot idea: solar heating
Reducing our carbon footprint
We are working to reduce our carbon footprint by making process changes, installing Best Available Technology (BAT) which is more energy efficient, reducing purchased energy (electricity and fossil fuel) by increasing our use of renewable energy – an approach that ultimately results in a reduction in carbon dioxide (CO2 ) emissions. Our new solar heating system at Ngodwana nursery is just one example of this approach.
Why it’s necessary
Heating at the nursery is required for root initiation, faster rooting and improved hedge growth during winter months. During the scoping process of the rebuild of Ngodwana nursery we investigated alternative green solutions to using fossil fuel energy to generate heat.
The solution
We eventually settled on solar thermal heating which is 100% green and which will be fully installed in 2020. The solar system is designed as a standalone ‘plug-in’ to the nursery heating reticulation network. The system designed is expected to deliver an average of 4,000 kWh per day during winter months – a total of 488,000 kWh over winter months with a solar radiation average of 4.8 kWh/m2/day.
How it works
The heat will be collected during the daylight hours by 216 solar evacuated tube systems and stored in an insulated 300 m3 water storage tank for the reticulation to the nursery’s hot ring main pipe. The solar thermal collectors consist of solar evacuated tubes that collect solar radiation from the sun, combined with a manifold on a steel frame. Water temperatures of 70 °C will be achieved and stored for circulation through the three rooting and two mother plant (hedge) structures.
The benefits
- Low operating costs
- Carbon neutral (100% green energy)
- Year-round heating, as and when required
- The blueprint for this system can also be rolled out to Sappi’s other commercial nurseries and is already in place in our Forestry Research Centre.