Growing Mashua: A Complete Profile
By Growing Home Greens Team · August 10, 2026
Mashua is a vigorous climbing Andean tuber crop and, botanically, a relative of the ornamental nasturtium already in this dataset, though it’s grown for its tubers rather than its flowers.
It wants a trellis
Give mashua something to climb and yields can reach up to four times what an unsupported, sprawling plant produces, up to about 20 pounds per plant on a trellis versus closer to 5 pounds on the ground. It’s a vigorous vine, so plan for real vertical space, not a token stake.
A short-day crop, like oca
Most mashua varieties won’t start forming tubers until after the fall equinox, around September 21, and aren’t ready for harvest until mid-November, the same short-day pattern as oca. That makes a long, frost-free fall essential in most climates. The variety ‘Ken Aslet’ is a real exception: it begins forming tubers earlier and can produce a reasonably good yield by mid-October, useful where an early frost would otherwise cut the season short.
Cool summers preferred
Mashua does best where summer highs stay under 80°F, and it’s easiest to grow in the maritime Pacific Northwest. Elsewhere, afternoon shade helps it cope with hotter summers. It’s hardy only to about USDA zone 9a, so in most of the country it’s dug and replanted annually.
Mashua has no recorded companions or antagonists in our data. See the full companion guide for mashua for how it’s tracked. In the Garden Designer, give it a trellis and plenty of vertical room rather than treating it as a low-growing root crop.
Source: Mashua (Tropaeolum tuberosum), Cultivariable.
Companion planting guide for Mashua · Find your planting dates
Typically viable in USDA zones 6-9. Not sure your zone? Look it up by ZIP code.
Method: Direct sow: Direct-sow outside. Mashua doesn't transplant well, or doesn't need the extra time indoors.
See exact start-indoors, direct-sow, and harvest dates for your zone →
How many Mashua plants fit per square foot?
Spacing: about 2 square feet per plant (square-foot-gardening spacing). Mature height: 2-8 ft.
Varieties worth considering
- 'Ken Aslet': Cultivariable singles this variety out as an exception to mashua's usual short-day tuber timing: it forms tubers earlier and can produce a reasonably good yield by mid-October instead of mid-November. (source)
Cited from the source shown next to each variety. We haven't grown these ourselves yet, so treat this as a research-backed starting point, not a personal endorsement.
Where to buy mashua seeds
As an Amazon Associate we earn from qualifying purchases. Some links on this page also go to other retailers we may earn a commission from as an affiliate, at no extra cost to you. We only recommend products with a genuine consensus of positive, independent reviews. See the sources cited on each item.
See it growing
Search YouTube for "growing mashua" videos → (a live search, not a hand-picked video; results vary and aren't vetted by us)
Pin this for later
Growing Mashua: A vigorous climbing relative of the ornamental nasturtium, grown instead for its tubers, which yield far better trellised than left to sprawl on the ground.
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