Editing Potato (section)

== Cultivation ==

{{anchor|Seed potato}}

=== Seed potatoes ===

Potatoes are generally grown from "seed potatoes", tubers specifically grown to be free from disease{{clarify|date=June 2024}} and to provide consistent and healthy plants. To be disease free, the areas where seed potatoes are grown are selected with care. In the US, this restricts production of seed potatoes to only 15 states out of all 50 states where potatoes are grown. These locations are selected for their cold, hard winters that kill pests and summers with long sunshine hours for optimum growth.<ref name="US Potato Board - Seed Potatoes">{{cite web |author=United States Potato Board |title=Seed Potatoes |url=http://www.potatoesusa.com/potato-products/seed-potatoes |url-status=dead |archive-url=https://web.archive.org/web/20150825053643/http://www.potatoesusa.com/potato-products/seed-potatoes |archive-date=25 August 2015 |access-date=6 October 2014}}</ref> In the UK, most seed potatoes originate in [[Scotland]], in areas where westerly winds reduce [[aphid]] attacks and the spread of [[Potato virus Y |potato virus]] pathogens.<ref>{{cite web |title=Seed & Ware Potatoes – Nuclear Stock |url=https://www.sasa.gov.uk/seed-ware-potatoes/nuclear-stock |url-status=live |archive-url=https://web.archive.org/web/20150910164423/http://www.sasa.gov.uk/seed-ware-potatoes/nuclear-stock |archive-date=10 September 2015 |access-date=12 June 2024 |website=[[SASA (Scottish Government)|SASA]]}}</ref>

=== Phases of growth ===

Potato growth can be divided into five phases. During the first phase, sprouts emerge from the seed potatoes and root growth begins. During the second, [[photosynthesis]] begins as the plant develops leaves and branches above-ground and [[stolon]]s develop from lower leaf [[axil]]s on the below-ground stem. In the third phase the tips of the stolons swell, forming new [[tubers]], and the shoots continue to grow, with flowers typically developing soon after. Tuber bulking occurs during the fourth phase, when the plant begins investing the majority of its resources in its newly formed tubers. At this phase, several factors are critical to a good yield: optimal [[soil moisture]] and temperature, soil nutrient availability and balance, and resistance to [[Pest (organism) |pest attacks]]. The fifth phase is the maturation of the tubers: the leaves and stems senesce and the tuber skins harden.<ref>{{cite web |title=Potatoes Home Garden |url=https://sfyl.ifas.ufl.edu/lawn-and-garden/potatoes-home-garden/ |access-date=14 August 2019 |website=sfyl.ifas.ufl.edu |publisher=UF/IFAS Extension}}</ref><ref name="JefferiesLawson1991">{{cite journal |last1=Jefferies |first1=R. A. |last2=Lawson |first2=H. M. |year=1991 |title=A key for the stages of development of potato (''Solanum tuberosum'')<!--- Mis-scanned in electronic versions as "Solatium". Print copies show the correct "Solanum". ---> |journal=[[Annals of Applied Biology]] |volume=119 |issue=2 |pages=387–399 |doi=10.1111/j.1744-7348.1991.tb04879.x |issn=0003-4746}}</ref>

New tubers may start growing at the surface of the soil. Since exposure to light leads to an undesirable greening of the skins and the development of [[solanine]] as a protection from the sun's rays, growers cover surface tubers. Commercial growers cover them by piling additional soil around the base of the plant as it grows (called "hilling" up, or in British English "earthing up"). An alternative method, used by home gardeners and smaller-scale growers, involves covering the growing area with [[mulch]]es such as straw or plastic sheets.<ref name="cornell1">{{cite web |title=Growing Potatoes in the Home Garden |url=http://suffolk-lamp.cit.cornell.edu/assets/Horticulture-Leaflets/Growing-Potatoes-in-the-Home-Garden.pdf |access-date=27 June 2010 |publisher=[[Cornell University]]{{NBSP}}[[Cooperative extension service |Extension Service]] |url-status=dead |archive-url=https://web.archive.org/web/20110516020007/http://suffolk-lamp.cit.cornell.edu/assets/Horticulture-Leaflets/Growing-Potatoes-in-the-Home-Garden.pdf |archive-date=16 May 2011}}</ref>

At farm scale, potatoes require a well-drained neutral or mildly acidic soil ([[pH]] 6 or 7) such as a sandy [[loam]]. The soil is prepared using deep tillage, for example with a [[chisel plow]] or ripper. In areas where irrigation is needed, the field is leveled using a landplane so that water can be supplied evenly. Manure can be added after initial irrigation; the soil is then broken up with a [[disc harrow]]. The potatoes are planted using a [[potato planter]] machine in rows {{convert|80|cm|in}} apart.<ref>{{cite web |title=Potato Production |url=https://pdf.usaid.gov/pdf_docs/pnadz110.pdf |archive-url=https://web.archive.org/web/20170227212730/http://pdf.usaid.gov/pdf_docs/pnadz110.pdf |url-status=dead |archive-date=27 February 2017 |publisher=USAID |pages=2–21 |access-date=4 June 2024}}</ref> At garden scale, potatoes are planted in trenches or individual holes some {{convert|15|cm|in}} deep in soil, preferably with additional organic matter such as garden compost or manure. Alternatively, they can be planted in containers or bags filled with a free-draining compost.<ref name="RHS planting">{{cite web |title=How to grow potatoes: Planting |url=https://www.rhs.org.uk/vegetables/potatoes/grow-your-own |publisher=[[Royal Horticultural Society]] |access-date=4 June 2024}}</ref>
Potatoes are sensitive to heavy [[frost]]s, which damage them in the ground or when stored.<ref>{{cite web |title=Potatoes |url=https://www.nsalg.org.uk/crop/potatoes/ |publisher=The National Allotment Society |access-date=5 May 2024}}</ref>

<gallery class=center mode=nolines widths=180 heights=180>
File:Planting Potatoes.jpg|Planting
File:Tractors in Potato Field.jpg|Field in [[Fort Fairfield, Maine]]
File:Potato plants.jpg|Immature potato plants
File:Potato bag cultivation.JPG|Potatoes grown in a tall bag are common in gardens as they minimize digging.
</gallery>

=== Pests and diseases ===

{{main|List of potato diseases}}

[[File:Phytophtora infestans-effects.jpg|thumb|[[Late blight]] ]]

The historically significant ''[[Phytophthora infestans]]'', the cause of [[late blight]], remains an ongoing problem in Europe<ref name="PlDis2011"/> and the United States.<ref>{{cite web |title=Organic Management of Late Blight of Potato and Tomato (''Phytophthora infestans'') |url=http://www.extension.org/pages/18361/organic-management-of-late-blight-of-potato-and-tomato-phytophthora-infestans |url-status=dead |archive-url=https://web.archive.org/web/20150702002959/http://www.extension.org/pages/18361/organic-management-of-late-blight-of-potato-and-tomato-phytophthora-infestans |archive-date=2 July 2015 |access-date=6 January 2012 |publisher=[[Michigan State University]]}}</ref> Other potato diseases include ''[[Rhizoctonia]]'', ''[[Sclerotinia]]'', ''[[Pectobacterium carotovorum]]'' (black leg), [[potato powdery mildew |powdery mildew]], [[powdery scab]] and [[Potato leafroll virus |leafroll virus]].<ref>{{cite web |title=Potato, Identifying Diseases |date=15 November 2016 |url=https://ag.umass.edu/vegetable/fact-sheets/potato-identifying-diseases |publisher=University of Massachusetts Amherst |access-date=5 May 2024}}</ref><ref>{{cite web |title=Potato Disease Identification |url=https://potatoes.ahdb.org.uk/knowledge-library/potato-disease-identification |publisher=Agriculture and Horticulture Development Board |access-date=5 May 2024}}</ref>

Insects that commonly transmit potato diseases or damage the plants include the [[Colorado potato beetle]], the [[potato tuber moth]], the green peach aphid (''[[Myzus persicae]]''), the [[potato aphid]], ''[[Tuta absoluta]]'', [[beet leafhopper]]s, [[thrips]], and [[mites]]. The Colorado potato beetle is considered the most important insect defoliator of potatoes, devastating entire crops.<ref name='Alyokhin'>{{cite book |chapter-url=http://www.potatobeetle.org/Alyokhin_CPB_Review_reprint.pdf |author1=Alyokhin, A. |date=2009 |chapter=Colorado potato beetle management on potatoes: current challenges and future prospects |editor1=Tennant, P. |editor2=Benkeblia, N. |title=Potato II. Fruit, Vegetable and Cereal Science and Biotechnology 3 (Special Issue 1) |pages=10–19}}</ref> The [[potato cyst nematode]] is a microscopic worm that feeds on the roots, thus causing the potato plants to wilt. Since its eggs can survive in the soil for several years, [[crop rotation]] is recommended.<ref>{{cite web |title=Potato Cyst Nematode |url=http://agriculture.vic.gov.au/agriculture/pests-diseases-and-weeds/pest-insects-and-mites/potato-cyst-nematode |website=Agriculture Victoria |accessdate=11 December 2019 |archive-date=2 December 2019 |archive-url=https://web.archive.org/web/20191202063605/http://agriculture.vic.gov.au/agriculture/pests-diseases-and-weeds/pest-insects-and-mites/potato-cyst-nematode |url-status=live }}</ref>

=== Harvest ===

[[File:AVR Puma 4.0 (cropped).jpg|thumb|left|A modern [[potato harvester]] ]]

On a small scale, potatoes can be harvested using a hoe or spade, or simply by hand. Commercial harvesting is done with large [[potato harvester]]s, which scoop up the plant and surrounding earth. This is transported up an apron chain consisting of steel links several feet wide, which separates some of the earth. The chain deposits into an area where further separation occurs. The most complex designs use vine choppers and shakers, along with a blower system to separate the potatoes from the plant. The result is then usually run past workers who continue to sort out plant material, stones, and rotten potatoes before the potatoes are continuously delivered to a wagon or truck. Further inspection and separation occurs when the potatoes are unloaded from the field vehicles and put into storage.<ref name="Johnson Auat Cheein 2023">{{cite journal |last1=Johnson |first1=Ciaran Miceal |last2=Auat Cheein |first2=Fernando |title=Machinery for potato harvesting: a state-of-the-art review |journal=Frontiers in Plant Science |volume=14 |date=2023 |issn=1664-462X |pmid=37284722 |pmc=10239890 |doi=10.3389/fpls.2023.1156734 |doi-access=free|bibcode=2023FrPS...1456734J }}</ref>

Potatoes are usually cured after harvest to improve skin-set. Skin-set is the process by which the skin of the potato becomes resistant to skinning damage. Potato tubers may be susceptible to skinning at harvest and suffer skinning damage during harvest and handling operations. Curing allows the skin to fully set and any wounds to heal. Wound-healing prevents infection and water-loss from the tubers during storage. Curing is normally done at relatively warm temperatures ({{convert|50|to|60|°F|°C|order=flip|disp=or}}) with high humidity and good gas-exchange if at all possible.<ref>{{cite book |last1=Kleinkopf |first1=G.E. |last2=Olsen |first2=N. |year=2003 |chapter=Storage Management |title=Potato Production Systems |editor1=J.C. Stark |editor2=S.L. Love |publisher=University of Idaho Agricultural Communications |pages=363–381}}</ref>{{-}}

=== Storage ===

[[File:Potato transportation to cold storage in India (1).jpg |thumb |Transporting to cold storage in India]]

Storage facilities need to be carefully designed to keep the potatoes alive and slow the natural process of sprouting which involves the breakdown of starch. It is crucial that the storage area be dark, ventilated well, and, for long-term storage, maintained at temperatures near {{convert|4|C|F}}. For short-term storage, temperatures of about {{convert|7|to|10|°C|°F}} are preferred.<ref name="crosstree">Potato storage, value Preservation: {{cite web |last=Kohli |first=Pawanexh |year=2009 |title=Potato storage and value Preservation: The Basics |url=http://crosstree.info/Documents/POTATO_STORAGE.pdf |url-status=dead |archive-url=https://web.archive.org/web/20200806192307/http://www.crosstree.info/Documents/POTATO_STORAGE.pdf |archive-date=6 August 2020 |access-date=12 July 2009 |publisher=CrossTree techno-visors}}</ref>

Temperatures below {{convert|4|°C|°F}} convert the starch in potatoes into sugar, which alters their taste and cooking qualities and leads to higher [[acrylamide]] levels in the cooked product, especially in deep-fried dishes. The discovery of acrylamides in starchy foods in 2002 has caused concern, but it is not likely that the acrylamides in food, even if it is somewhat burnt, causes cancer in humans.<ref name="cruk">{{cite web |date=15 October 2021 |title=Can eating burnt foods cause cancer? |url=https://www.cancerresearchuk.org/about-cancer/causes-of-cancer/cancer-myths/can-eating-burnt-foods-cause-cancer |publisher=Cancer Research UK}}</ref>

Chemicals are used to suppress sprouting of tubers during storage. [[Chlorpropham]] is the main chemical used, but it has been banned in the EU over toxicity concerns.<ref name="epp">{{cite news |last=Epp |first=Melanie |date=12 April 2021 |title=The Worry with CIPC |work=EuropeanSeed |url=https://european-seed.com/2021/04/the-worry-with-cipc/ |access-date=12 June 2021}}</ref> Alternatives include [[ethylene]], spearmint and orange oils, and [[1,4-dimethylnaphthalene]].<ref name="epp"/>

Under optimum conditions in commercial warehouses, potatoes can be stored for up to 10–12 months.<ref name="crosstree" /> The commercial storage and retrieval of potatoes involves several phases: first ''drying'' surface moisture; ''wound healing'' at 85% to 95% [[relative humidity]] and temperatures below {{convert |25 |°C |°F}}; a staged ''cooling phase''; a ''holding'' phase; and a ''reconditioning'' phase, during which the tubers are slowly warmed. [[Ventilation (architecture) |Mechanical ventilation]] is used at various points during the process to prevent condensation and the accumulation of carbon dioxide.<ref name="crosstree" />

{| class="wikitable" style="float:right; width:12em; text-align:center;"
|+Potato production <br>{{small|2023, millions of tonnes}}
|-
|{{CHN}} ||93.4
|-
|{{IND}} ||60.1
|-
|{{UKR}} ||21.4
|-
|{{USA}} ||20.0
|-
|{{RUS}} ||19.4
|-
|'''World''' ||'''383'''
|-
|colspan=2|{{small|Source: [[FAOSTAT]] of the [[United Nations]]}}<ref name="faostat">{{cite web|url=http://www.fao.org/faostat/en/#data/QC|title=Potato production in 2023, Crops/Regions/World list/Production Quantity/Year (pick lists)|date=2025|publisher=UN Food and Agriculture Organization, Corporate Statistical Database (FAOSTAT)|access-date=31 March 2025}}</ref>
|}