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In the 2023 growing season, Fargro collaborated with Ferring Nurseries in Worthing, West Sussex, to grow a crop of 6,000 0.5L cyclamen peat-free and without application of conventional chemical pesticides. The goal was to establish a model for growing ornamental crops that are cost-effective and environmentally friendly.
The outcome was an impressively low crop-loss rate, significantly below 1%. This resulted in a high-quality and uniform crop, allowing Fargro to offer a cost-friendly price for consumers and a good margin for Ferring Nurseries.
Here, Jack Haslam, technical development specialist at Fargro walks us through the five-step process of holistic crop management:
1. Growing media
The first step was to decide on which growing media would be used – always a critical factor for crop success. With peat-free mixes the medium is generally more open and less retentive of water and nutrients than traditional peat mixes.
While it’s not possible to replicate the properties of peat exactly, a blend of wood fibre, coir, green compost, pine bark, perlite, granulated clay and a wetting agent was developed. This custom-mix offered adequate porosity for root oxygenation, effective water retention, a slightly acidic pH that is resistant to change, and good nutrient-holding capabilities. Importantly, it also fostered a community of beneficial microbes, which thrive more in peat-free media. These microbes provided benefits such as improved nutrient availability, disease prevention, and steady growth of roots and shoots.
2. Nutrition
We strategically employed a combination of conventional mineral and organic fertilisers, with organic options making up the majority of the added nutrition. It's important to understand the key differences in the mechanisms of action between these two types of fertilisers.
Mineral fertilisers provide nutrients in a form readily available for immediate uptake by the plant. Yet, their simple chemical structure means they are less tightly bound within the growing medium, making them prone to leaching.
While, organic fertilisers arrive as part of a complex organic matrix, tightly bound and less susceptible to leaching. Yet, the nutrients they contain are not immediately accessible to the plant. Instead, soil microbes play a critical role in breaking down organic fertilisers into their mineral form, which the plant can then absorb. Importantly, this microbial activity closely aligns with the plant's metabolism, ensuring that nutrition was available when needed. This synchronisation minimises the risk of root burn and encourages the development of a robust root system.
To facilitate this microbial activity, we introduced beneficial microbes into the growing media through the use of green compost. The consistent and steady delivery of the correct nutrition promoted the development of strong and healthy roots, leaves and flowers. This enhances the crop's marketability and significantly reduces the vulnerability to disease and the attraction of pests, creating a harmonious and sustainable environment for plant growth.
Healthy and uniform root development
Growing media, fertiliser and analysis cost: £0.051 per plant (£51 per 1,000 plants)
The importance of soil analysis
During the trial a number of soil analyses were conducted, this is especially important when growing in peat-free media because the growing media chemical and nutritional properties can fluctuate more than peat-based mixes. Evaluating the chemical and nutrient profile is crucial when assessing nutrient availability and the plant's ability to absorb them.
In peat-free media, it was observed that nutrients became more accessible at higher pH levels, making a nearly neutral pH less concerning. Additionally, when using organic feed, it's essential to note that lower Electrical Conductivity (EC) values do not imply reduced nutrient availability. The lower EC is a result of the distinct nutrient release pattern of organic products, which aligns with the plant's requirements, ensuring a tailored nutrient supply.
A stability of EC levels between different samples was noted, which highlighted the consistency in nutrient delivery from the organic feed. This consistency benefits the plant by providing a steady nutrient supply, facilitating balanced growth and development, ultimately yielding robust and healthy plants.
Another noteworthy aspect is the lower levels of nitrates in organic feeds. Organic feeds typically contain minimal nitrate, with most of the nitrogen (N) in the form of ammonia. Soil microbes play a role in converting ammonia into forms accessible to plants. This lower nitrate level is not a cause for concern; in fact, it prevents overfeeding of nitrate, which can lead to rapid but weak growth, and increased susceptibility to pests and diseases.
3. Irrigation
Irrigation plays an important role when growing peat-free because the mixes generally retain less water which increases the risk of the crop drying out. To combat this, a granular and liquid wetting agent was used. This ensured there was sufficient water retention in the media to support plant growth. With the use of organic fertiliser, less water is needed for nutrient delivery to the roots, making it ideal for peat-free growing. Growing on the dryer side also helps with pest and disease management. The crop was watered every three to four days.
4. Disease management
A thriving plant exhibits strong natural resistance to diseases, thanks to its robust internal immune system and the protective qualities of its healthy leaves and flowers. For cyclamen, the main focus is on preventing botrytis, which appears as browning on the flowers.
The exceptional crop health enabled us to implement an innovative and cost-effective disease management strategy that eliminated the need for conventional chemical fungicides. Instead, they adopted a preventive approach, using a combination of Romeo, containing denatured brewer’s yeast (cerevisane); Taegro, containing the bacteria Bacillus amyloliquefaciens; and SBPI, which contains a number of phyto-safe surfactants.
This program proved remarkably cost-efficient. It achieved an impressive 100% control rate against botrytis, with no visible flower damage observed throughout the crop's growth cycle.
Healthy flowers, showing no signs of botrytis
Disease spray program cost: £0.0006 per plant (£0.60 per 1,000 plants)
5. Pest management
Peat-free materials retain organic matter that undergoes decomposition by fungi. These fungi become a food source for sciarid flies, resulting in higher levels of these flies in peat-free media compared to peat-based mixes. The increased presence of sciarid flies becomes a crucial factor to consider in peat-free growing.
To address this challenge, a multi-faceted approach to pest management was adopted. First, we reduced fungal growth and limited sciarid fly populations by implementing integrated organic fertilisation, creating a less humid environment. Additionally, specific control measures were used, including yellow sticky traps and the application of Steinernema feltiae nematodes, alongside the introduction of the predatory beetles, Atheta coriaria.
Three traps were placed in a 50m2 area, with two monitoring cycles during the crop's growth (totalling six traps) to track sciarid fly levels. Three applications of nematodes were also used, which parasitised and eliminated sciarid fly larvae, and a breeding colony of Atheta coriaria were introduced to prey on soil-dwelling larvae throughout the growth period.
The crops were also observed for potential threats from thrips, whitefly, aphids and spider mites. Fortunately, no infestations occurred during the growing process.
A two-week cumulation of pests on a trap
Overall cost of the pest control program: £0.014 per plant (£14 per 1,000 plants).
In summary, Fargro and Ferring Nurseries successfully grew a healthy, high-quality crop of 6,000 cyclamen in 0.5L pots while maintaining cost-effective practices. Crop loss due to pests and diseases remained significantly below 1%. The estimated cost for media, fertilisers, soil analysis, pest and disease management per plant was £0.0656 (£65.60 per 1,000 plants).
Fargro would like to thank Ferring Nurseries for its collaboration on this project. For more information, please contact Jack Haslam on 01903 256856 or email jack.haslam@fargro.co.uk.