Latest news articles for the horticulture sector.

Management notes 2016

Latest management notes for 2016 are now available using the links below:

November 2015

Autumn spray options

A very variable Bramley crop this year has left some orchards with heavy extension growth and numerous water shots. If you are concerned about the lack of fruit bud initiated for blossom next spring it isn’t too late to apply a spray of the growth regulator ‘Cerone’ (a.i. 2-chloroethylphosphonic acid). This is a recent addition to growth regulators allowed on apple trees, having proved its worth on cereal crops previously. When sprayed onto trees after fruit picking, ‘Cerone’ closes down any late season vigour. There is also strong evidence that if applied before leaf fall starts, it can change terminal bud into fruit bud, even on Bramley. The maximum dose in any year is only 0.75 litres per hectare (0.5 pints per acre). It should be effective if applied as a single spray treatment at this rate. There is an argument for better effect by applying it as two half-rate sprays, ten to 14 days apart’ although weather or surface conditions may not permit two treatments in November. Another benefit of this product is that it provides some plant defence to stressed trees, because it's active ingredient is converted into a form of systemic fungicide (similar to ‘Alliette’) on absorption.

Where an orchard has shown significant canker (Neonectria) infection on stems and fruit, it will benefit from a late season fungicide treatment to dry up live lesions, suppress further spore production and reduce the number of new infections. Active ingredients available for this purpose include copper oxychloride (sold as ‘Cuprokylt’) and tebuconazole (sold as for example ‘Fathom’, ‘Folicur’, ‘Orius 20EW’). Applied at 5 per cent and 50 per cent leaf fall, any of these products will help protect scars and wounds from fresh canker attack. Remember that Neonectria sporing can occur in any wet weather where temperatures are 6 degrees centigrade or higher.

Biological control of spider mite

Over the past number of years there has been an increase in spider mites (two-spotted mite, red or glasshouse mite and fruit spider mite) in a range of crops in protected and nursery stock plant species. Biological control is the main control in many situations following mites developing resistance to a range of pesticides.

At the Horticulture Centre, Greenmount, we use biological control agents for spider mite in a range of crops. We have identified a number of factors which need to be considered specifically in the use of biological control in spider mite control. These are as follows:

Crop surface area - as the crop grows over the season the leaf cover surface area also increases, therefore you may need to increase the volume of biological predators to give better coverage especially in high density cropping.

Limitations of the predator species - of the biological predators available for spider mite control specific species are more effective at different stages of the spider mite population and population density.

Temperature - one of the most voiced concerns of using biological control is temperature. However when you look at the temperature requirements of most biological control predators, including those which can be used for spider mite, they are able to cope with temperatures between 8 and 30 degrees.

Relative humidity - some predator species, for example Phytoseiulus persimilis, find it difficult to work in very dry warm conditions and need a relative humidity of at least 60 per cent while the other species used as a control, Amblyseius californicus, can tolerate a lower humidity.

Over-winter - spider mites have a great capacity to over-winter within a structure and crop. They go through a dormant-like period (diapauses) of not eating and reproducing (survival instincts) making them a serious threat from early in the season. On-going vigilance is important especially with reducing egg numbers before the main cropping periods.

August 2015

A ‘Unique’ weed control system

Most plants for the garden market are grown in containers which growers have difficulty keeping free from weeds, mosses and liverwort. Growers in the past have relied on chemical weed killer applied on the surface of the container. Chemical weed control is no longer an option for container plant production leaving growers with high labour costs for hand weeding. Paul Downard from Unique Garden Products in County Armagh has developed a system for weed control using sustainable local materials. The system consists of a flexible disc which is placed on top of the container after potting. To help investigate this product Paul obtained an Innovation Voucher from Invest NI and the product was evaluated at the Horticultural Centre, Greenmount Campus in 2014.

David Kerr from Greenmount Campus reports “we have tested the Unique Pot topper in nursery conditions and found it is flexible and easy to use preventing weeds, including moss and liverwort, from developing. The topper is based on natural fibres which allow it to hold moisture resulting in less frequent watering.

Results using specialist moisture recording equipment show that the moisture level in containers with a Unique Pot topper increased to a higher level after watering and remained longer at the higher level than containers without a mulch.

This method of weed control has created a lot of interest and David Kerr presented an overview of the project work at the International Plant Propagators Society Conference in Denmark in winter 2014. Here there was particular interest in the sustainable nature of the product and the potential to reduce herbicide usage.

Paul Downard from Unique Garden Products said: “the work at Greenmount has confirmed the performance of the topper as an effective weed control product. I am finding more interest from growers in this local product, especially with the reduced availability of weed killer products for ornamentals in containers.”

A grower adopting this new technology is Liam Greene of Plantation Road Nursery, County Armagh. Liam said: “we are increasingly using Unique Pot toppers at the potting stage and this is reducing our labour input for weed control significantly. We grow a wide range of plant sizes for supply to the landscape trade and find that the range of sizes of pot toppers available is helpful.” 

Chrysanthemum cut flower production

The most important locally grown cut flower crop is Chrysanthemums. Most of the locally grown Chrysanthemums are ‘bloom’ type (a single large flower per stem). Sales of locally grown blooms and sprays start in October and normally finish in December.

A cut flower project at Greenmount Campus is currently demonstrating different planting densities for bloom varieties. The project is investigating three different planting densities (24, 32 and 64 plants per square metre) to measure the impact on crop health and flower quality. Each of the three density plantings consists of four different Chrysanthemum varieties – Cassandra Pink, Dragon Red, Fred Shoesmith Improved and Shamrock Green. The crops are pinched to give a different number of stems per plant depending on planting density – three stems at 24 plants per square metre, two stems at 32 plants per square metre and one stem at 64 plants per square metre.

As the growing season continues conditions for fungal infections can increase. Of particular concern for Chrysanthemum growers is Botrytis (grey mould). This disease is difficult to control and can spread quickly. The early signs of infection include spots on the leaf or flower petals. These reduce quality resulting in crop losses and non-marketable stems. Prevention methods are the best means of protection. Non-chemical prevention methods include good ventilation/air movement, heating greenhouses early in the morning to lower humidity, removing crop debris and watering crops using trickle tape to prevent leaves becoming wet. A fungicide programme that includes biological fungicides can be used to reduce the risk of fungal infections.

June 2015

Cut flowers

Growers are now harvesting cut flower crops including scented stock, lilies and alstroemeria. An important factor in preventing pests and diseases is a proactive Integrated Pest Management (IPM) programme. Maintaining good air ventilation in greenhouses and using a combination of fungicides, including biological products such as Serenade, are important factors in preventing fungal attacks.

This month a number of outdoor crops, including peony, are ready for harvest. As wet and warm weather promotes fungal attacks, in particular Botrytis, in the stem and flower bud of peony, it is critical a suitable IPM programme is implemented throughout the growing season. This is in addition to cultural controls such as removing infected stems and ensuringgood hygiene practices for equipment and pickers.

Weed control continues to be an issue with a range of control options available including herbicides, mulches and manual removal. Two key considerations when deciding on the best control option are crop stage and type of weed (annual/perennial). A common problem in cut flower crops are annual weeds such as chickweed (Stellaria media) and shepherd’s purse (Capsella bursa-pastoris). These are soil or water borne seeds that compete with the crop for nutrients and space especially at early crop stages. Planting plug plants through a mulch can be effective in reducing weed cover but does not totally eliminate manual weeding. 

Recent results of herbicide trials on cut flower crops by the Horticulture Development Centre have shown a variation in the effectiveness of herbicides and effect on crops.

In late June direct sow sunflower at 28-35 seeds per square metre indoors and ornamental kale (Brassica) outdoors at 110 seeds per square metre or 75 plug plants per square metre in the greenhouse. For both crops the high density ensures smaller flower heads that make them suitable for floristry displays.

Controlled fertiliser application for ornamental crops

One of the main developments in ornamental crop growing has been the increasing use of Controlled Release Fertilisers (CRF). Conventional fertilisers are soluble in water and nutrients disperse quickly after application.

Controlled release fertilisers have a physical coating that allows nutrients to flow out over time. The release of fertilizer from CRF granules is dependent on temperature and in warmer conditions, such as in a protected structure, release is quicker. Another benefit of CRF products is that nutrients, such as nitrates nitrogen, can be released regularly to more accurately meet plant needs since they cannot be stored by the growing medium and are readily leached.

Continuous improvement of CRF products has resulted in a large range of different products effective from three to four months up to 16-18 months and the ability to release trace elements. Although the use of CRF is well established, there have been questions about their performance in our cooler climate. This was investigated in a project at the Horticulture Development Centre from 2013 to 2015.

Hedging plants of Prunus lusitanica were potted in July 2013 with no additional feeding and assessed in November 2014.The photograph below shows the results.

From left to right eight to nine month CRF, 12-14 month CRF and eight to nine month CRF ‘High End’. Prunus lusitanica produced satisfactory growth in all treatments. Prunus grown in 12-14 month CRF, both outside and inside, produced equivalent or better growth than the eight to nine month products in our climatic conditions. This was more evident in the second season.

Specimen plants grown at higher rates of fertiliser when moved to 10 litre pots were also investigated. The photograph below shows common laurel grown in 12-14 month CRF at 5 kg per cubic metre on the left and on the right 12-14 month CRF at 7.5 kg per cubic metre. Using the higher rate of fertiliser produced larger plants over an 18 month growing period. The additional fertiliser is a relatively low cost for growers in relation to the value of the plant. 

April 2015

Substituting imports in the ornamental plant market - a new pot plant Hydrangea crop

Growing Hydrangea as a pot plant is a relatively new market under investigation at the Horticultural Centre, Greenmount Campus. Working with growers, imported plant products are being evaluated for local production.

Growing more crops locally helps nursery businesses gain market share and supports employment. Import substitution reduces transport costs, as a typical garden plant can cost up to one euro to transport from Holland.

Derek Hanna from Hanna’s nurseries in County Antrim supplies wholesalers and is investigating new crops including Hydrangea. Derek said: “The demonstration at Greenmount Campus gave me the information I need to make decisions on the cropping plans for my nursery.”

David Kerr, CAFRE’s Ornamental Sector Development Adviser from Greenmount Campus reports: “We sourced young cold stored plants from Germany and have looked at systems of production, including using additional lighting and growth control methods.”

The Hydrangea crop was grown using heat from the biomass boiler burning woodchip. Ten varieties are being assessed to allow selection of the best performing colours. The cropping period at this time of year is 13 weeks.

Bulrush Horticulture has developed dedicated growing media to enhance the growth and flowering of Hydrangea and this technology is also part of the project.

The product is sold in a sleeve and initial feedback on the quality of the pot product has been very encouraging.

If you wish to view this crop, please contact David Kerr on 028 3752 9059 or mobile 07899 864 343.

Safe use of pesticides training for growers

Anyone who uses pesticides (approved for use in agriculture, horticulture and forestry) in their job is legally required to have a City and Guilds / NPTC Certificate of Competence in the Safe Use of Pesticides for Farmers and Growers. A current exemption in United Kingdom law is commonly known as ‘grandfather rights’. This allows anyone born on, or before, 31 December 1964 to use Plant Protection Products (PPP’s) authorised for professional use on their own or their employer’s land, without a certificate of competence although they should still be suitably trained and competent for the job.

After 26 November 2015 anyone who relied on ‘grandfather rights’ will have to achieve a Certificate of Competence through a training and assessment programme. There arevarious strands to the pesticides training delivered by CAFRE at Greenmount and Loughry Campuses:

  • if you were born after 31 December 1964 select from the following programme:
    • PA1 - Foundation module (Safe Use of Pesticides). Everyone must do this. You then can choose from the following module(s) appropriate to your business on completion of PA1
    • PA2a –Ground crop sprayer (tractor mounted)
    • PA3a – Broadcast orchard sprayer with air assistance (mounted or trailed)
    • PA6a – Handheld applicator (knapsack sprayer)
  • if you were born born on, or before 31 December 1964 you can select from the courses listed above or from the following programme:
    • grandfather Rights, Unit 051 and Unit 052(knapsack sprayer)
    • grandfather Rights, Unit 051 and Unit 053(boom sprayer)

Grandfather Rights Unit 051, which is mandatory, involves one day of classroom based training and covers the same areas as PA1. Grandfather Rights Unit 052, which is optional, also involves one day’s training and covers the same areas as PA6a. Grandfather Rights Unit 053 (optional) covers the same areas as PA2a.

For more information on Safe Use of Pesticides courses for farmers and growers please contact CAFRE Short Course Administration on 028 9442 6880 or by e-mail: You can also apply online.

It is important to remember that professional pesticide products must not be purchased or used after 26 November 2015 unless the operator applying the product is certificated.

January 2015

Biofilter at Greenmount Campus

One of the most common challenges, in even the best set up spraying operations, is dealing with spills as well as washings from containers and sprayers. Biofilters were developed to eliminate or minimise the risk of negative environmental impacts arising from the rinsing and cleaning of sprayers.

What is a biofilter?

Biofilters are basically an organic filter system. They work because pesticides have an affinity for biological matter and so bind to the biomix used. Biomix is generally a mixture of straw, peat free compost and soil. This provides conditions for enhanced microbial degradation of the active ingredients over time. The technology of biofilters for the bioremediation and breakdown of pesticide actives has been proven to be effective through trials carried out across Europe.

Biofilter at Greenmount Campus

The current design of the Greenmount Campus biofilter is based on three Intermediate Bulk Container’s (IBC’s) of a nominal 1000 litre capacity with their tops removed and with the fitting of linked plumbing to allow liquid distribution from the top container to the middle and bottom containers. It is important that the liquid spreads uniformly over the biomix surface within each container.

What can a biofilter treat?

Biofilters are designed to treat non-hazardous pesticide solutions. Examples include small spills and drips that may occur during pesticide handling and mixing, run-off from the pesticide handling area and equipment washings. However, biofilters are not a substitute for best practice and every effort should be made to avoid spills or splashes of pesticide concentrates, for example, always place a drip tray under the induction hopper. Best practice also requires that in most cases, the first set of tank washings is sprayed onto the target crop ensuring the maximum dose is not exceeded.

What are the advantages of a biofilter?

Biofilters offer the following advantages:

  • a farmer friendly, practical, ‘build it yourself’ method of disposing of left-over pesticides, sprayer tank and other washings
  • most materials required for biofilter construction can be found on-farm or can be easily supplied
  • approved by Government Authorities (currently England, Scotland and Wales)
  • a relatively small area is required for the complete set up
  • biomix only has to be replaced every five years
  • spent biomix can be recycled on land after the required resting period

How much does it cost?

Costs vary depending on whether a new handling area is required, the final choice of system, and whether farm labour and /or second hand materials are included in the cost. A typical biofilter system costs from £500 to £1,500.

Benchmarking for horticultural businesses

Benchmarking in horticulture involves recording business costs and comparing them with other businesses. Benchmark results provide detailed management information indicating the strengths and weakness of a business and identification of areas for improvement.

As a horticulture producer, key business decisions are required on an ongoing basis and it is important that these decisions are based on sound facts relating to the physical and financial performance of your business. Benchmarking is an extremely valuable tool to help with this decision making process, should it be short term agronomy decisions to improve production or longer term investment in new crops.

CAFRE’s Greenmount Campus Horticulture Benchmarking Programme is a farm management accounting system that offers you the opportunity to record your production costs and output and compare your results to previous years and with other similar farms.

For any 12 month period, all expenses attributed to your business are recorded. This is mainly covered by your VAT book. To complete the picture, a record of income generated by the business over the same 12 month period is needed.

With your assistance the necessary input sheets are completed during a visit to your business. Data from the input sheets is put into the benchmarking programme and a confidential financial report is generated. The benchmark report provides a complete breakdown of costs of production and all the associated margins for your horticulture business. 

Most importantly the report also shows averages and best of group for similar growers for comparison purposes.

A key element of the benchmarking process is group feedback for growers in the same sector of horticulture. This is a confidential service available to horticultural producers in Northern Ireland, which can be accessed by contacting your CAFRE Horticulture Development Adviser.

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