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Written on 9 November 2024, by Frank van der Linden (Senior agronomist/storage specialist at Omnivent)
At the start of the storage season each year, we begin with our storage advice. Note: This storage advice is based on conditions in North-West Europe. If you want advice for your region, contact us. The content of this advice has been carefully compiled. However, results may differ with specific conditions of your product and/or defects in storage equipment. Therefore, when in doubt, do not hesitate to contact us.
Check your storage computer before storing
Before you start storing, check that your storage computer is still functioning properly. It is best to always leave your Omnivent storage computer on, but older types such as the ACT-20 can sometimes show a time-out alarm after a long period of inactivity.
Then go to section 00 ACT20 Terminal, page 2 Installation, line 15 Automatic clear timeout alarm, value ‘On’.
Using outside air for cooling and drying
It must be possible to cool and dry with outside air at night, and depending on the product temperature, also during the day. The minimum dew point difference can be set at -1°C, the minimum difference outside-product at -1°C. The lowest dew point difference that is still drying is -0.5°C.
In recent days, the relative humidity (RH) and dew point outside are such that there are sometimes few moments when drying is possible. Remember that using a heater can lower the RH, and therefore the dew point, allowing you to dry sooner and longer.
An additional advantage is that the product temperature does not become too low, which means that drying with outside air can last longer.
If you do not have mechanical cooling, try to lower the product temperature slowly so that you do not reach the final temperature too early. This should not be reached until mid-December.
Dry your potatoes as quickly as possible
For potatoes, it is important to dry as quickly as possible. Adhering moisture should be removed. Do this with a ventilation capacity of 100%. Damp soil and rotten tubers/bulbs should also be dried as quickly as possible to enable long and problem-free storage.
How are the conditions for storing potatoes this year?
Smooth harvest
Almost all potatoes are harvested now, with some exceptions where fields are still slightly green. Especially plots that were planted late are often still green. As long as the foliage is still green, further protection against potato blight and Alternaria is necessary because otherwise leaf and tuber damage will occur.
This year there are still quite a lot of mother tubers present. If these tubers show subcutaneous or early rot then care must be taken to dry them well to prevent contamination of neighboring tubers.
Due to the wet weather, snail damage and wireworm damage also occur, but these have (almost) no adverse effects on storage life.
At some places, batches with Phytophthora in the tuber occur. Here too, it is important to start drying immediately to prevent further spread of rot.
Remember that the minimum temperature for wound healing is 10°C. This process takes 10 to 14 days. At higher temperatures, wound healing is faster, temperatures between 12 and 15°C are ideal.
Blackspot bruise sensitivity
This year the bruise sensitivity is much higher. Careful harvesting and storage is the message!
Potato storage settings for each storage phase
| To storage Manual control | Try to bring the product in as much as possible in 1 day to prevent temperature differences between the batches. Adhering moisture must be removed as quickly as possible by means of ventilation. Start ventilating immediately with outside air and do this for at least 5 hours/day. Use heaters if necessary to dry. Pay attention to the dew point difference. A minimum difference of -0.5°C is required for drying, i.e. the dew point outside is lower than the dew point of the product. Set -1°C on the storage computer, -2°C is ideal. |
| Warm up | Only necessary if the product temperature is too low (below 10°C) |
| Drying/wound healing (ACT) or Intensive drying (Omnicuro) | Set the minimum and maximum product temperature between 12-18°C The ideal temperature is 15°C, at this temperature wound healing takes about 7 days. Do you have a dry product and less than 2% rot? Select the “Cooling/Storage” program. Do you have wet soil or more than 2% rot? Activate program “Drying/wound healing” or with Omnicuro “Intensive drying”. In the Time block settings, set the ‘max. fan stop’ to 4:00 hours. Minimum valve position 20%. Set the desired product RH to 85%. Make sure that the ‘Minimum duct temperature’ is at least 1 degree lower than the ‘Minimum desired duct temperature’ |
| After-drying (no desired RH can be set here, but this is possible with “Intensive drying”) | This is an easier but also more limited drying program to set. The desired starting duct temperature is 2°C higher than the starting temperature of the product. Preferably use the “Drying/wound healing” program when using ACT or “Intensive drying” when using OmniCuro |
| Cooling/storage | When the product is dry enough, you can start cooling slowly. If you can only cool with outside air, try to reach the desired end temperature mid-December. November often still has warm days. Lower the temperature by 0.5°C/day, for seed potatoes 0.3°C/day. Use the following settings at Limit Values (look for heading ‘Outside’): Minimum temperature difference outside-product -1°C Min. dew point difference outside-product -1°C (possibly -0.5°C) Max. dew point difference outside-product -15°C Stop internal ventilation when the delta temperature is below 1°C (Omnicuro ‘maximum temperature difference between sensors’). Set ‘Maximum time fans off’ to 24 hours. In ACT, set desired RV 0% to switch off RH control. In the Omnicuro, no RV needs to be set, except when an RV meter is present. Then set 95%. |
Dry in time before using sprout inhibitors
Sprout inhibition can start as early as November. So it’s important that your potatoes are dry by then. So don’t save on ventilation in the first days and weeks of storage!
Are you unsure about the conditions and the storage of your potatoes?
The Omnivent representative in your region will provide advice on settings and will be your point of contact for any questions, including questions about cooling. You may already find your answer among the frequently asked questions.
Region UK/Canada/USA
Ronnie Laing
T: +44 (0) 794 006 7458
E: Ronnie.Laing@omnivent.nl
Technical problem / malfunction
Are you experiencing a technical malfunction? That’s unpleasant! Fortunately, we are 24/7 available by phone to help you.
Cooling malfunction: T: (+31)6 – 53 42 14 36
Overige storingen: T:. (+31)6 – 55 14 66 09
