Tragopogon porrifolius

Salsify is grown similarly to other root vegetables like parsnip and carrots and thus require similar attention.[13][14] Sowing can be done in late summer or early winter[13] to foster an early growth.[12] Planting can also be done in early spring about 100 days before the first frosts in a well prepared soil, preferably a loam or silt-loam.[14] It should be done at the depth of 1.3 to 2 cm. Spacing between rows should be around 45 to 60 cm and the seeds should be separated by 3 cm approximately. This represent 12 g of seeds per 10 m of row for the cultivar 'Mammoth Sandwich Island'. A thinning to 5 cm between the plants is needed when the seedlings reach 5 cm.[13] T. porrifolius needs deep and loose soils which are not too dry for a good development of the taproot. Stony or waterlogged soils have negative effects on yields and hamper harvesting. Other root crops, legumes and cereals have been mentioned as possible preculture. T. porrifolius is a moderate feeder, therefore the application of fresh manure does not benefit yields. During the main growing period a good water supply prevents potential branching of the taproot.[15]

There are no specific requirements known for the cultivation of T. porrifolius, but they have been successfully cultivated in temperate climate zones.[9] The seedlings need a temperature of 8–16 °C to germinate and the plant will freeze between −1.1 and −1.6 °C. T. porrifolius can cope with low temperatures and is not injured by light freezing.[15][16]

The seeds need 8–10 days of germination time. T. porrifolius is a biennial plant. In the first year only the vegetative parts of the plant are developed. In autumn, the energy is stored in the root system, which is depending on the variety more or less branched. In the second season the generative purple flowers evolve.[15] They bloom from early to mid summer.[9]

The taproots are usually harvested from late autumn onwards (later than October in the Northern Hemisphere) and during winter. Harvesting after a frost is favoured to improve the taste of the root. After flowering, the taproot becomes stringy and inedible.[15] The taproots can be stored in traditional clamps although refrigerated storage has been recommended at 0 °C and 90–95% relative humidity for 2–4 months.[9][16]

Few pests or diseases affect T. porrifolius. White rust (Albugo tragopogonis) is the most common disease of T. porrifolius. Closely related wild species (e.g. Tragopogon pratensis), black salsify (Scorzonera hispanica), gerbera (Gerbera) and sunflower (Helianthus annuus) are also found to be hosts of this fungus. At an early stage chlorotic spotting is visible on leaves and stems. These develop during the course of disease into small white blisters.

Occasional problems are reported with rust diseases caused by Puccinia hystericum, Puccinia jackyana and Puccinia scorzonera.[17] Mulching with oats and the use of spring vetch (Vicia sativa) or blue tansy (Phacelia tanacetifolia) as cover crops reduces the number of fungi infecting seedlings and roots. The following fungi have been isolated from T. porrifolius seedlings and roots: Alternaria alternata, Fusarium culmorum, Fusarium oxysporum, Penicillium spp., Rhizoctonia solani and Sclerotinia sclerotiorum.[18]

When the rows are planted too close together, powdery mildew (Erysiphe cichoriacearum) can affect the plants.[16]

When the roots are left in the ground over winter, mice and voles may nibble them.[16]

The plant is edible,[19] but the roots and leaves are most palatable when collected before the flower stalk is produced.[20] The root is noted for having a mild taste when uncooked, described as like asparagus or oysters, from which the plant derives its alternative name of oyster plant. The outer layers can be scraped off, with the root dipped in cold water to preserve its colour.[20] If too tough for eating, they can be boiled with a pinch of baking soda and a change of water.[20] Raw young roots can be grated for use in salads, but older roots are better cooked. They can be added to soups, stews or stir-fries. Salsify purée (alone or including potato) is recommended with fish.[21]

The flowering shoots can be used like asparagus, either raw or cooked and the flowers can be added to salad, while the sprouted seeds can be used in salads or sandwiches.

Raw salsify is 77% water, 19% carbohydrates, 3% protein and contains negligible fat (table). In a 100 gram reference amount, raw salsify supplies 82 calories and moderate contents of riboflavin, vitamin B6, vitamin C, manganese and phosphorus.