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BP2015 – Crop Storage focus

Publication Date: 
28 October 2015

BP2015 – Crop Storage focus

Crop storage is rightly commanding a new focus, with AHDB Potatoes staff at BP2015 eager to share new advice.

ONE hot topic at BP2015 is sure to be storage. Unless producers embrace advice and services developed over recent seasons they could find it increasingly difficult to deliver consistent, quality produce, at least cost, whilst meeting regulatory requirements, particularly around key sprout suppressant chlorpropham (CIPC).

“Potatoes often spend more time in the store than in the ground, so getting stores right, and fit for the future, is a big priority,” says Rob Clayton, Strategy Director at AHDB Potatoes. 

“It’s an on-going battle, with quality specs moving, regulatory requirements moving, and the whole shape of the industry moving. It’s no secret that the industry isn’t as big as it used to be, and we are still over-capacity, so it really is a case of improve your store to stay in the game.”

He commends the good work, diligence and commitment of growers, and suggests they can get a good return on their levy investment from the support available at BP2015 in Harrogate on 12 and 13 November 2015. Admission is free if pre-registered at

Newly updated StoreCheck+ is a case in point, offering store leakage measurement and energy usage advice. “It offers a pretty quick payback through improved crop quality and lower electricity bills.”

Each year about 3 m tonnes of potatoes are stored in around 2,500 stores by about 1,000 producers, notes Adrian Cunnington, Head of Sutton Bridge Crop Storage Research. But more producers need to heed its advice.

“There is a wide variation in the level of efficiency being operated in GB stores, with some otherwise comparable stores costing three times more to run per tonne than others. That could push electricity costs from £3/t to £9/t.”

Storage 2020

Storage 2020 is AHDB Potatoes’ over-arching initiative to help the industry meet storage demands up to 2020 and beyond.

“We realised too few new stores were going up, partly due to the tough economic climate, so wanted to encourage producers to improve existing ones where the economics of investing in a new facility did not stack up,” says Mr Cunnington. “It’s about getting more from what we have.”

Five key areas are being targeted:

  • Leaky stores – on a windy day warm air leaking into a store can increase running costs by as much as 50%, and heighten the risk of condensation, encouraging disease. StoreCheck can pinpoint problems.
  • Overhead-throw box stores – uneven air distribution can raise cooling costs and risk of the legal Maximum Residue Level for the key sprout suppressant CIPC. Fitting air dividers to force air along pallet slot bases improves ventilation and temperature control.  
  • Bulk stores with no fan speed control – low fan speeds help circulate CIPC fog evenly and running fans at 80% once the store is dry cuts costs by as much as 50%. Adding inverters to vary fan speed can bring payback in 2-3 years.
  • Stores used for cereals and CIPC-treated potatoes – Red Tractor Combinable Crops audits are focusing on this, since the CIPC MRL for cereals is the limit of detection. Dual use stores are likely to become unfeasible, with significant on-farm implications.
  • Fan replacement – replacing a 20-year-old fan with a new more efficient one gives better results with less electricity. £3000 spent on a fan which helps cut electricity costs of maybe £6000/year can soon pay.


So far Sutton Bridge Crop Storage Research and Farm Energy Centre have run StoreCheck in about 60 stores. A third were outside leakage guidelines, with no clear link to store age.

For 2015/16, StoreCheck+ includes a consultation with a storage/energy expert to discuss how the audit results might be addressed. Cost is £540-640/store, depending on store capacity.

Sprout suppression 

Sprout suppression is a big reason for improving store facilities. After 50 years CIPC still accounts for over 90% of all post-harvest sprout suppressant applications, equivalent to 1.2 million tonnes of stored crop. For many businesses supplying fresh and processing potatoes there is currently no clear alternative.

CIPC’s registration is due for renewal in 2017 and its future very much hinges around the CIPC Stewardship Group’s ability to prevent any Maximum Residue Level (MRL) breaches.

Good progress has been made, especially in bulk stores, with total CIPC use 51% lower than in 2002 and 2006. But box stores are proving more challenging. “As an industry we have to go further,” Mr Cunnington stresses. “Everybody needs to be compliant.” See

The maximum permitted dose of CIPC is currently being reduced each year towards a total dose of 36 g/tonne (or less) in 2017 and ventilation during application is expected to become a mandatory label requirement from 2017. Producers relying on CIPC need to be aware of this and to plan changes to stores to be compliant, both now and in the future, without impacting crop quality.

The harsh truth is that many growers may have to accept that their stores no longer comply with CIPC best practice. Modest investments in modifications to improve airflow, costing maybe £3-5,000, are now due.


Some hope is offered by alternative sprout control options, although most are likely to be used in an integrated programme with CIPC.

Dimethylnaphthalene (DMN; 1-4Sight) from DormFresh has been registered for use in the Netherlands but no date for UK approval is available yet. It is effective in pre-pack and processing stores and, when approved, is expected to be marketed by BASF.

Registration of 3-decen-2-one (SmartBlock) is also hoped for in 2016. It is also likely to be applied by contractor as a hot-fog and will be marketed by Certis.

Ethylene has been available for a few years, with Restrain and BioFresh supplying application equipment for use in fresh potatoes. On-going work at SBCSR hopes to overcome any unwanted effect on fry colour. 

Spearmint oil (R-carvone) has full UK registration (as Biox-M) and is being used in more pre-pack stores. But in most processing stores it is likely to be cost-prohibitive.

Variety dormancy characteristics, maleic hydrazide and different marketing strategies may also help reduce reliance on CIPC. An Innovate UK project is also looking at computer modelling to better predict store airflows to further enhance CIPC usage.

Another element of Storage 2020 is TIPS –The Interactive Potato Store. The interactive on-line tool shows, in a very user-friendly way, how the many research projects SBCSR and Farm Energy have been involved in can help on a farm. Register at

Bottom line

The relatively small cost of finding out if your store is running to the best of its ability, and improving performance where necessary, could be the difference between staying in potatoes and being forced out. Harvesting the best advice at BP2015 could be the key to staying in.

Case Study: StoreCheck

Greenvale has successfully used StoreCheck to target air leaks in fresh produce stores in the Borders region, with five stores tested last year and results compared. “It confirmed what I feared, and justified spray foaming two converted stores,” explains store manager John Hutchison of Craigswalls near Duns, Berwickshire. A re-test this year showed huge improvements, with air loss down from well over 20% per hour to nearer 4%. “That cuts energy costs, which on their own will give us a payback within 3 years. Fridge longevity will benefit too, since with it won’t be working so hard, or so long. We should need less ethylene sprout suppressant too. “The whole process was very, very straightforward, with professional operators and no disruption to us.” The one downside of such an air-tight store is the need to monitor carbon dioxide levels carefully. “I’d certainly recommend StoreCheck to other growers,” he concludes.

Case Study: Investing in storage

Investing in a state-of-the-art 900t bulk store for crisping potatoes is no small matter. So Lancs producer Andrew Webster worked closely with SBCSR experts, store designer Welvent, builder Wareings of Wrea Green and his CIPC contractor to ensure his store was as future-proof as possible, and CIPC compliant both now, and for years to come. “We spoke to a lot of growers, to hear their problems, and hope we’ve got round most of them.”

Farming as A W & M A Webster from Hollin House Green Farm, Aughton, Ormskirk, Lancs, he grows 150 acres of Lady Rosetta, Taurus and Shelford, for Mercian Limited.

Wooden slatted ventilation channels account for half the concrete floor area, tapering from 12in to 4in to maintain air pressure across the full width. Crop can be stored to a depth of 14ft.

Condensation from cold bridging is avoided by extending purlins to create a 7in air gap between the 4in composite panels mounted on the exterior and the steel girders inside, so warm air can be circulated as needed. “Little tweaks like that can make a big difference.”

Storage costs per tonne are strictly monitored, with inverters to control fan speed and regular probe checks helping to preserve tuber quality and keep all-peak tariff electricity costs in year one to £1.92/t. Andrew plans to be at BP2015 to gather more tips. As he says: “you never stop learning.” 

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