Twin-skinned tunnels: If you are heating tunnels at this time of the year, the added value of having twin-skinned tunnels quickly becomes obvious. When comparing the heating costs of a single-skin and twin-skin tunnel you will see there is a 45 per cent saving with the latter.
Winter injury: Plant death can occur from waterlogging (mainly through poor bed drainage or growing media), drought (water unavailable because of frozen compost), physical damage (due to heavy snow or ice), wind chill or wind scorch. Applying an anti-transpirant helps to prevent water loss in plants. Make sure that vulnerable crops, particularly spring-flowering species, are suitably protected from strong winds by windbreaks or fleece. Plants that are pot-thick have better root protection from reduced pot surface exposure. Warm days on frozen pots of evergreens with low levels of transpiration can produce drought symptoms on the foliage. If we get a warm spell for several days, fleece them to reduce water loss.
Field planning: The potato cyst nematode (PCN) directive (22007/33/EC) that came into force this year on 1 July not only affects seed potato producers but any growers using old or new potato land. Landowners renting their land for the production of planting material of a PCN host or plants likely to be grown in rotation with potatoes come within the scope of the directive. Confirm whether any fields you rent are subject to PCN regulations and check whether they are classified "clean". You may be asked to pay for PCN testing when you hand back the land. The Food & Environment Research Agency has produced two helpful sheets - see www.fera.defra.gov.uk and click on "Plant, Bees & Seeds" then "Plant Pests & Diseases". Land preparations make major differences to planting and lifting and contribute greatly to plant growth. Keep tractor movements to a minimum to avoid compaction and maintain levels of humus in mineral soils by introducing green manure crops.
Cold stores: Watch the temperature and humidity levels in cold stores. Consider spraying stored material with chlorothalonil as protection against fungal growth on the stems and old foliage, which can become a breeding ground for fungi.
John Adlam is managing director at Dove Associates www.HorticultureWeek.co.uk/nursery for recent articles