About This Plant
Mashua (Tropaeolum tuberosum), also called isaño, añu or cubio, is a hardy Andean tuber crop grown from 2,400-4,300 m in Peru, Bolivia, Ecuador and Colombia, and at sea level in cool maritime climates like coastal New Zealand. A relative of the garden nasturtium, it is famously rustic: no pest or disease seriously constrains it, foliage tolerates light frost, and it thrives on the residual fertility left after a fertilized potato crop. Plants form a dense, weed-smothering ground cover whose twining stems can climb past 2 m with support. The peppery tubers, among the richest known plant sources of glucosinolates, are traditionally sweetened by a few days of sun-curing before eating. Mashua is a strict short-day crop: tubers form only once day length drops below about 12 hours, and the crop needs 6-9 months in the ground, so site and season matter more than feeding. No hydroponic production has been published; all verified production is in well-drained soil.
How to Grow Mashua
Learn how to grow Mashua from seed to harvest in 250 days. Intermediate difficulty. Complete nutrient guide, pH/EC requirements, and growing conditions for soil & container.
Backed by 23 peer-reviewed citations.
Nutrient Requirements by Growth Stage
Mashua is a low-demand crop by the design of its own farming system: Andean growers traditionally plant it after potato specifically to use the residual fertility left by that crop (in Peru such fields are called 'kqalpares de papa'), or as the last crop before fallow, and the same residual-fertility practice is…
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Growing Environments
Mashua is an outdoor cool-climate crop, grown from the high Andes (2,400-4,300 m) to cool maritime lowlands like coastal New Zealand and British Columbia. It fails in continental climates where hard frost arrives before autumn days shorten below the roughly 12-hour tuberization threshold…
Temperature
Mashua is a cool-climate crop. Its home range sits at 2,400-4,300 m in the Andes, where annual mean temperatures are 8-11°C, and it is cool conditions, not altitude itself, that the plant needs: it crops well outdoors at sea level in coastal New Zealand and near Vancouver. Foliage tolerates brief -1°C frosts and young plants can recover fully from -2 to -4°C, but -5°C destroys the tops, and a -3.5°C autumn frost ended one Bolivian trial outright. Short spells around 30°C are tolerated, but sustained warmth is a stress, not a target. In controlled environments the demonstrated optimum is 19±2°C, from in-vitro propagation work. Hold plants cool and steady through the long season.
Humidity
No published humidity requirement exists for field-grown mashua. The crop tolerates the misty, cloudy weather of the eastern Andean ranges and also withstands short dry spells…
Light
Mashua is a strict short-day tuberizer, and this is the single most important thing to know about growing it: tubers initiate only once day length falls below about 12 hours, with roughly 9 hours reported as optimal, and plants failed to tuberize entirely under 14-20 hour days. Vegetative growth tolerates longer days;…
Airflow
No verified source reports airflow, wind or ventilation requirements for mashua in any setting, so no numeric target is given. As an outdoor Andean field crop it is naturally well ventilated, and its one documented moisture-linked disease pressure, Sclerotinia rot, appears only under exceptionally wet conditions…
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Hydroponic System Compatibility
No hydroponic or soilless production system has a published trial for mashua; every verified production account is rainfed field soil, hilled twice. The earlier note claiming compatibility with 'sand, TIS and aeroponics' conflated temporary-immersion tissue culture (TIS-RITA), a laboratory micropropagation technique…
Growing Media
Every verified account of mashua production uses well-drained mineral soil, typically under low or residual fertility. The crop tolerates the widest soil pH of the Andean tubers, roughly 5.3-7.5, and produced 18-36 t/ha even on an acid pH 5.0 trial soil…
Container Specs
No verified source describes container cultivation of mashua: no pot volume, depth, drainage spec or material has been published, so no container numbers are asserted. What the field evidence establishes is geometry and behaviour a container grower must respect: plants are spaced 30-40 cm apart in rows 70-80 cm apart…
Training & Support
Mashua needs no trellis, stakes or training. Plants start erect and then relax into a semi-prostrate, densely matted ground cover that smothers weeds once the canopy closes; leaf area index reaches 4.7-5 in fertilized stands…
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Propagation
Mashua is grown from tubers, not seed. Andean farmers set aside part of each harvest as next season's planting stock, about 900-1,300 kg of seed tubers per hectare, and plant them whole once the first seasonal rains are established, from mid-August through October in most of Peru and Bolivia, extending to early…
Harvesting
Mashua is ready 6-9 months after planting, around 250 days for most plantings, when the vines yellow and brown, drop their lower leaves, and sometimes push tubers up to the surface. Harvest by hand, opening the soil with a hoe, and pick a dry-soil day so the tubers come out clean…
Planting Calendar
Mashua's calendar is set by rain and day length. In the central Andes, plant seed tubers with the onset of the first reliable rains, mid-August to mid-October in much of Peru and Bolivia, extending to early November where rains establish later; Bolivian programs cite July-September planting with harvest April-June…
Common Issues
Mashua is famously rustic: surveys of Andean germplasm found no pest or disease that seriously constrains the crop, and fungicides are not recommended even when pathogens are present. The disease to know is the aphid-borne virus complex, Tropaeolum mosaic potyvirus (TropMV) plus Tropaeolum 1 and 2 potyviruses, spread…
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