Soil cultivation and structure
- Appropriate cultivation is required to enable maximum rooting and uptake of water and nutrients.
- 60 cm depth of uncompacted soil may be sufficient for irrigated crops, a greater depth may be required in the absence of irrigation.
- Examine soil structure:
- Use of a penetrometer can identify areas of compaction.
- Examine with a soil pit – if compacted horizon fractures horizontally, cultivation may be beneficial.
- Do not create problems: De-stoners and de-clodders may readily create a pan immediately below seed depth, if used in wet conditions.
For more details see: Soil cultivation.
Depth of planting
- Shallow planting may offer an advantage in cool conditions, deep planting may offer an advantage in warm conditions.
- “Deep” planting may be considered as 20 cm settled soil above the seed tuber.
- “Shallow” planting may be considered as 10 cm settled soil above the seed tuber.
- Deep planting provides a greater volume of soil in which tubers can grow and reduces the risk of tubers at the edge of the ridge becoming green.
- Depth of planting should be considered in relation to soil temperature: seed should be planted when the soil temperature at planting depth is at least 8 ºC (see also: Date of planting and Influence of temperature, on this page).
Date of planting
- There is, physiologically, little benefit from planting before soil temperatures of 8 ºC are achieved.
- Potatoes planted earlier, or during unseasonably warm periods, may be vulnerable to low temperatures and soil borne diseases.
- Mean daily air temperature may provide a good indication of soil temperature at 10 cm depth; temperatures can be expected to be lower at greater depths.
- Long term average air temperatures (LTA) can be used to indicate indicate when a mean daily air temperature of 8 ºC can be expected.
- Late planting reduces tuber yield mainly by a reduction in the duration of tuber bulking but the number of progeny tubers may also be reduced.
- Experiments for the PRG suggest that maximum canopy size, maximum rate of tubers bulking and maximum number of progeny tubers may occur at the time of the “optimum” planting date of 8ºC.
- The experiments also indicate a possible planting window of two weeks either side of the optimum, though emergence and development occur more slowly at the earlier dates.
- Early planted crops may benefit from fleece or polythene covering to advance the onset of tuber bulking but:
- when ambient temperatures are low covers result in only a small increase in temperature,
- use of covers can restrict the rate of bulking, particularly if they are left on too long,
- early season applications of nutrients and late blight fungicides cannot be made.
- More information on crop covers.
More information on date of planting.
Influence of planting dates and harvest dates on tuber blemishing diseases
- Blemishing diseases may be reduced by shortening the growing season, which reduces build up of infection on progeny tubers.
- Should harvest be brought forward or planting be delayed?
- Effects of earlier harvest:
- harvesting conditions improve
- there is a probability of lower soil moisture reducing bacteria build up
- higher temperatures can result in curing starting as soon as tubers are lifted, thus reducing the risk of bacterial and fungal diseases.
- Effects of delayed planting:
- a shortened growing season may be partly or wholly compensated by an increased bulking rate
- a shorter period from planting to emergence may also reduce stem and stolon canker caused by Rhizoctonia, which in turn reduces the risk of black scurf infection of tubers.
For more information see: Tuber blemishing diseases.
Notes on planting
Planting 2014 (Influence of climate on emergence and growth; influence of storage conditions on dormancy break)
Early dates of crop production 2011 (Use of crop covers to advance early development)
Date of planting 2009 (PRG experiments; conclusions on the research programme)
Date of planting 2008 (PRG experiments)
Date of planting 2007 (PRG experiments)
Date of planting 2006 (PRG experiments)
Planting date 2005 (Includes PRG database analysis)
Planting depth 2005 (Includes ridge size and shape)
Planting temperature 1997 (Includes PRG planting date experiment)
Planting date 1996 (Modelling effects of different planting dates)
Planting accuracy 1994 (Chapter begins down the page)
Notes for 1993 (Chapter 3: Planting depth)