{"id":2243,"date":"2020-02-03T03:12:38","date_gmt":"2020-02-03T03:12:38","guid":{"rendered":"https:\/\/greenmanpublishing.com\/?p=2243"},"modified":"2020-02-03T03:34:55","modified_gmt":"2020-02-03T03:34:55","slug":"oca","status":"publish","type":"post","link":"https:\/\/greenmanpublishing.com\/index.php\/2020\/02\/03\/oca\/","title":{"rendered":"Oca"},"content":{"rendered":"\n

Oxalis tuberosa <\/em><\/p>\n\n\n\n

Introduction<\/strong>: In its native Andes oca is second only to the potato in\nimportance as a staple root vegetable. This is largely because it can be\nproductive under more adverse growing conditions. <\/p>\n\n\n\n

Unlike its compatriot the potato, oca has never been very well\nknown outside its native range. This is somewhat surprising when you consider\nof its many virtues. I think it\u2019s time is coming though and that it is going to\nbecome much more popular as a garden crop in the near future. For some reason\nit is already quite widely grown in New Zealand and it is known as New Zealand\nyam in some places.<\/p>\n\n\n\n

Oca is propagated vegetatively from tubers\nlike the potato. These are absolutely beautiful, coming in different colors\n(red, yellow, pink, white, purple) and having a shiny, jewel-like quality.<\/p>\n\n\n\n

Ease of\ngrowing: <\/strong>Oca is a rugged and\nindependent plant; it tolerates poor soil and harsh climates, is fairly easy to\ngrow and can be very productive. The only drawbacks are that it is day length\nsensitive and needs a fairly long growing season (see Climate<\/strong> below).<\/p>\n\n\n\n

Climate<\/strong>: Oca is native to subtropical mountains and grows best with a\nlong, relatively cool growing season (they don\u2019t like extreme heat). <\/p>\n\n\n\n

Oca is day length sensitive, needing short days (less than 12\nhours) to produce tubers, which means that it doesn\u2019t really start producing\ntubers until after the fall equinox. For this reason it does best in mild areas\nwhere fall frosts come late. It is well suited to my California garden, where\nit grows as a low maintenance perennial. <\/p>\n\n\n\n

About Oca<\/strong>  
Perennial
Hardiness zones: 7 – 11 (in colder areas tubers must be taken inside for the winter)
Growing temp: 55 (65 – 75) 95\u00b0F
Plant out: On last frost date
Days to harvest: 170 – 240
Yield per plant: 2 – 3 lb
Plant size:     
Height: 12 – 18\u02dd     
Width: 18 – 24\u02dd  
<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

If your garden gets early frost in September or October oca is\nunlikely to do well without protection (you can cover them to protect from\nlight frost). Dedicated growers have grown them in poly tunnels, but of course\nthis increases the amount of work required.<\/p>\n\n\n\n

Crop value:<\/strong> Oca isn\u2019t anywhere near as productive as the potato, but is a\npretty good substitute for it in the kitchen. As it is day length sensitive it\nwill only produce tubers in fall, which means you can only get one crop a year.\nNewer varieties are less day length sensitive and lower in oxalic acid, which\ncan only add to its appeal.<\/p>\n\n\n\n

Nutritional content<\/strong>: The tubers are fairly nutritious, being high in carbohydrate,\ncalcium, iron, phosphorus and vitamin A. <\/p>\n\n\n\n

Oca also contains oxalic acid, which is considered bad because it\ncan combine with calcium and prevent it getting absorbed by the body. However\nthis is no more of a problem in oca than it is in spinach (which is not much of\none).<\/p>\n\n\n\n

Soil<\/strong><\/p>\n\n\n\n

pH\n5.3 \u2013 7.8<\/strong><\/p>\n\n\n\n

Oca is known for its ability to grow and produce well in poor\nsoils (so long as they are well-drained). However it will be most productive in\na fertile, sandy soil. <\/p>\n\n\n\n

Soil\npreparation<\/strong>: For maximum productivity\nincorporate 2\u02dd of compost into the top 8\u02dd of soil. Also put a handful of an\norganic fertilizer mix in each planting hole.<\/p>\n\n\n\n

Planning<\/strong><\/p>\n\n\n\n

When<\/strong>: Oca is really a fall crop, so there is no\nrush to get it into the ground in spring (unless your growing season is very\nshort of course). Start planting around the last frost date. A hard frost will\nkill anything above ground (don\u2019t worry it will regrow), so wait until the last\nfrost date (or later) before planting. If your growing season is short you can\nstart them inside in 4\u02dd pots and plant them outside a couple of weeks after the\nlast frost date.<\/p>\n\n\n\n

Where<\/strong>: Oca is commonly planted as an annual crop like the potato. If\nyou live in a mild climate you can also give it a permanent home in the\nsemi-wild or forest garden. It needs\nfull sun. <\/p>\n\n\n\n

Planting<\/strong><\/strong><\/p>\n\n\n\n

This is an easy crop to get started as it is grown from tubers.\nPlant these 2\u02dd deep and 24\u02dd apart. If you intend to earth them up, this will be\neasier if you plant them in rows.<\/p>\n\n\n\n

Starting\nindoors<\/strong>: If your growing season is short you\ncan start the tubers in 4\u02dd pots to save some time. <\/p>\n\n\n\n

You might also start indoors if you have just bought some\nexpensive tubers and don\u2019t have many (to ensure there are no mishaps).<\/p>\n\n\n\n

Spacing<\/strong>: Space the plants 12 – 24\u02dd apart (or even wider in some cases).\nThe bigger the spacing the larger the plant will get (they can reach 24\u02dd in height\nand 24\u02dd in width). They start out fairly upright and compact, but eventually\nsprawl into a heap, with stems rooting where they touch the ground. Wider\nspacing tends to produce bigger plants which means more big tubers, which is\ngood. <\/p>\n\n\n\n

The plants don\u2019t need a lot of space for the first few months, so\nyou might want to interplant something between them.<\/p>\n\n\n\n

Care<\/strong><\/p>\n\n\n\n

Watering<\/strong>: Oca doesn\u2019t need a lot of water, but for best production the\nsoil should be kept evenly moist. The plants produce a lot of foliage through\nthe summer and the bigger they get the more tubers they will produce. <\/p>\n\n\n\n

Oca will be more productive if you give it extra water when the\ntubers start to\nform (not too much though).<\/p>\n\n\n\n

Weeding<\/strong>: Keep the young plants well weeded. Established plants can compete with weeds quite well.<\/p>\n\n\n\n

Earthing up<\/strong>: If the plants are earthed up after 3 months, they will produce\nmore tubers (this isn\u2019t absolutely necessary though). <\/p>\n\n\n\n

Mulch<\/strong>: This is helpful to conserve moisture and suppress weeds,\nespecially if you are growing your tubers in a wilder part of the garden. You\ncan\u2019t easily mulch and hill up though, so must do one or the other.<\/p>\n\n\n\n

Fertilizing<\/strong>: The plants will benefit from feeding in late summer when tuber\nstart to form. You could either side dress with a fertilizer mix or feed with compost tea or liquid kelp.<\/p>\n\n\n\n

Pests<\/strong>: I haven\u2019t noticed any insect pests or diseases (which is a nice\nchange from the potato). However rodents will eat the stored tubers if given the chance.<\/p>\n\n\n\n

Frost protection<\/strong>: The tubers start to develop quickly after the fall equinox and\nthe longer they can keep growing after this time, the bigger the harvest.\nProtect them from early frost with anything you have (ideally fleece frost\nblankets, but cardboard or plastic sheet will also work). Keep protecting them\nfor as long as you can, ideally until mid November or December. <\/p>\n\n\n\n

Harvesting<\/strong> <\/p>\n\n\n\n

When<\/strong>: The tubers don\u2019t start to develop until the\nday length drops below 12 hours, which may be anywhere from 4 – 6 months after\nplanting.<\/p>\n\n\n\n

After the tops have died down (or been killed) you wait a couple\nof weeks for the tubers to mature and then start to harvest. As a mountain crop\nit has evolved to deal with frost and the tubers continue to grow for a while\nafter the tops are dead. If it gets seriously cold before this time and the\nsoil threatens to freeze, then you will have to harvest the tubers, otherwise\nthey may be damaged.<\/p>\n\n\n\n

In mild climates you can simply leave the tubers in the ground and\nharvest as needed. Any you don\u2019t harvest will start to grow again the following\nyear.<\/p>\n\n\n\n

How<\/strong>: The tubers are found fairly close to the plant and are quite\nshallow, so are easily dug with a fork. Most are also pretty brightly colored\nand so easy to\nspot.<\/p>\n\n\n\n

Storage<\/strong>: The best place to store the tubers is in the ground. In colder\nclimates you should cover them with mulch to prevent the ground freezing. If it\nisn\u2019t practical to leave them in the ground, they can be stored like carrots,\nin a root cellar in damp sand or sawdust (or simply in slatted wooden boxes).\nThey will keep in a plastic bag in the fridge for several weeks. <\/p>\n\n\n\n

Unlike potatoes the tubers don\u2019t need to be kept in the dark, in\nfact if they are exposed to sunlight it reduces the amount of oxalic acid they\ncontain and makes them less sour.<\/p>\n\n\n\n

In their native Andes they are often dried for storage.<\/p>\n\n\n\n

Seed saving<\/strong>: Oca produces perfect (have both male and female parts) 5\npetalled yellow flowers. You don\u2019t need to worry about them though, as oca is\nusually propagated vegetatively. <\/p>\n\n\n\n

You need to save some tubers for replanting, so don\u2019t eat them\nall. I usually eat the larger tubers and save the small ones for replanting.<\/p>\n\n\n\n

Unusual growing ideas<\/strong><\/p>\n\n\n\n

Ornamental<\/strong>: The plants have attractive clover-like foliage and are pretty\nenough to be grown as an ornamental border. Though of course this border won\u2019t\nlook so pretty when you dig it up.<\/p>\n\n\n\n

Containers<\/strong>: Oca will grow well enough in containers filled with fertile soil\nmix, but they will need to be fairly big if you are going to get many tubers\nfor your efforts. <\/p>\n\n\n\n

They can also be grown in grow bags as described in Potatoes<\/strong>.<\/p>\n\n\n\n

To save bed space some people grow then in containers for a while\nand plant them out when they start\nto get big.<\/p>\n\n\n\n

Perennial<\/strong>: In a mild climate oca will grow quite happily as a perennial,\nyou just have to leave it alone. <\/p>\n\n\n\n

Varieties<\/strong><\/strong><\/p>\n\n\n\n

Finding any oca tubers to plant isn\u2019t easy and finding named\ncultivars is even harder. The tubers come in a range of colors, but mostly\npink, red, purple and yellow (or a mix thereof). Some newer varieties may be\nlower in oxalic acid. <\/p>\n\n\n\n

Kitchen use<\/strong><\/p>\n\n\n\n

The root can be used in the same ways as the potato, though they\ndon\u2019t need peeling and are easy to clean. They can be boiled, baked, roasted,\nfried and used in soups. Unlike the potato it is also quite good raw, being\ncrisp and slightly tart. In Mexico they are eaten with salt, lemon and chile\npepper. They can also be pickled.<\/p>\n\n\n\n

In its native Andes they sometimes leave the tubers in sunlight to\nimprove their flavor. Apparently this reduces the amount of oxalic acid they\ncontain and increases their glucose content.<\/p>\n\n\n\n

The growing tops are also edible and can be added to salads.\nHowever they should be used in moderation as they contain oxalic acid.<\/p>\n","protected":false},"excerpt":{"rendered":"

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