PSI Bulletin: August 2025
No. 08/25 SUBSCRIBER EDITION
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Dear Subscriber,
Welcome to the August Synopsis bulletin from Potato Storage Insight for all our regular subscribers.
It's a hectic countdown now to the start of lifting, with August ebbing away and September just around the corner, so many crops are now having desiccant applied as growers prepare for harvest.
We have a few tips this month on what to have to hand as a store managers' kit
And here are some seasonal tips as part of our regular Best Practice feature...
Best practice
Topical tips for August
Many growers have been reluctant to apply MH in the highly-droughted conditions of the last few weeks, fearing it would check growth to such an extent it could kill plants off. But that seems to have been the outcome for some crops in the worst hit areas anyway with canopies collapsing in the dry conditions before any application could be contemplated.
From a long-term storage angle, a lack of residual control is a concern, especially as some varieties have been showing signs of sprouting in the ridge, especially in unirrigated situations where they have been subjected to a long, hot and dry summer. Extra vigilance will be needed once stores are loaded to secure early treatment of any stocks showing signs of trigger-happy growth. Contact action products like spearmint oil or orange oil may be required for this purpose. Consult your BASIS-qualified agronomist for recommendations.
There is a body of thought that the growth we have been seeing is not necessarily break of dormancy but perhaps more akin to another form of alternate growth alongside some of the second growth, misshapes and secondary tuberisation that appear to be
commonplace.
The other major issue to focus on when loading into store is skin set. Potatoes rely on their skins to provide that all-important two-way barrier to prevent moisture escape and to stop diseases getting in. Without skin set the crop is exposed to both risks: any skinless area will lose moisture at something like a hundred times the rate of a proper, fully-set skin. Some stronger crops, such as Markies, are putting up a fair bit of resistance to an accelerated demise but others are past the point of no return. With the field conditions we have seen, many have died off early which will help to provide that important suberised barrier (although it can also lay crops open to infection from problems such as black dot). Warm temperatures also speed up the skin setting process which is key to long-term protection against weight loss, especially in warm stores needing plenty of ventilation to remove field heat and reduce crop temperatures.
That said, with extremely dry soils and high dry matter content, crops will be hugely prone to both damage and bruising. External damage will expose susceptible crops to the risk of dry rot infection, if it remains warm, although curing should be rapid at current field temperatures. Bruising will be much harder to avoid and we may need all the tools in our armoury to keep levels down to acceptable levels. Working through harvesters to minimise drops, cushion transfers and retain soil on the web will be time well spent.
Second growth and 'sprouting' in the ground are other factors to watch for this season
Store managers' kit
Here are a few tips on the kind of kit you might like to have to hand as a store manager. A lot of this will be down to personal preference but, as a starter, here are some suggestions, clockwise from bottom left:
Torch: battery or rechargeable*
Hand-held 'probe' thermometers
Personal CO2 alarm
Anemometer for measuring air speed
Workwear: gloves, hi-visibility thermal jacket/gilet, bump cap, safety boots (not shown)
Apple Tag or similar for lone working traceability (may not work inside store - check!)
Store Managers' Guide
Head torch
*Back-up torch (important if you use a rechargeable main torch as they seldom give any warning of impending loss of charge...). Phone torch is of course an alternative back-up.
Phone/camera for notes and sample recording. May also link to your store controller and/or stock recording system.
Technical insight
How air behaves (or not!)
This month I wanted to remind all of you out there that the one thing you must not compromise on when it comes to high quality potato storage is airflow.
I have spent the last few weeks visiting a lot of stores around the Eastern counties and am still amazed at the number with compromised stacking arrangements that do not provide for optimal airflow through the crop.
I won't bang on too much about short circuits again. Yes, there is probably some air penetrating a fairly large percentage of the boxes (or even bulk) in most stores but it could be so much better...
Remember that wherever you are trying to apply air, the flow will take the line of least resistance. So - with the vast majority of stores relying on passive airflow - it is simply not going to dry or cool those isolated boxes in the back corners or a 'headland' cross-stack of solid-sided boxes that the air cannot penetrate.
Don't overfill stores! Narrowing the gap between the roof and the top boxes compromises the air 'throw' that is so important for getting air to the far end of the store. If air can't distribute, it will return to the fans by leaking through boxes and by-pass the crop at the end of the store furthest from the fans/fridge.
Tortuous air paths don't work. If air has a difficult job getting through over-filled boxes, narrow openings or routing round lots of sharp corners, the chances are that the resistance to flow will be too great and the air simply won't go there. Whenever air is turned 90°, blown over a rough surface or through a fan guard, it generates resistance to the flow and the air will most likely take an easier rout leaving crop starved of ventilation. Any affected boxes stay warm, wet and generally create an environment that encourages disease or sprouting.
Snippets
Regular readers may recall that PSI flagged up a few suggestions on energy use (as kWh/tonne/day) earlier in the year. These are shown again below.
Well, now is the time to start implementing the recording that will give you that data. Why not record your pre-storage meter readings today so you know you have them noted down and can start to see how your store performs against these guidelines?
Plans are being put into place to run another Potato Storage Day in 2026. Events have taken place in 2024 and 2025 and organisers Simon Faulkner and Adrian Cunnington are on the lookout for a venue for next May. Further details will be released in the coming months.
Forthcoming events
If you are hosting a potato or agricultural industry event, please send details to admin@potatostorageinsight.com. Key dates for your diary with relevance to the potato sector in the coming months in UK and Europe include:
August
Wed 27 - Thu 28 UK Breeders' Potato Variety Days 2025
Caythorpe Farms, Lincolnshire. NG32 3EZ
September
Tue 2 PSI One Day Store Management Course, Greetham, Rutland. LE15 7SN.
Wed 3/ Potato Europe
Thu 4 Annual international working exhibition, Lelystad, The Netherlands
November
Wed 19 - Thu 20 BP2025 - the British Potato Event, Yorkshire Event Centre, Harrogate
Exhibition, seminars and industry awards dinner on the Wednesday evening. Save the dates!
Details from: bpinfo@warnersgroup.co.uk
December
Tue 9 - Wed 10 CUPGRA Conference, Cambridge
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Synopsis is written by Adrian Cunnington and published by Potato Storage Insight Ltd., 45 Main St., Gedney Dyke, Spalding, PE12 0AJ. UK.
© Potato Storage Insight Ltd. 2025
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