A vine assigned to a living support must be sown after the support is established — corn ~6 in (~15 cm) tall, roughly 2-3 weeks — not at the same time.
Well established · costly if ignored → warn
How it works
Load. A bean vine on an immature, poorly-anchored stalk pulls it over; extension guides key the delay to the support's height (corn ~6 in) as a proxy for it being rooted enough to bear the climbing load.
What to do about it
Sow the vine 2-3 weeks after the support, once it is about 15 cm tall.
The evidence
Evidence: confirmed against 2 sources in the research-based literature.
the 2 sources
Cornell Garden-Based Learning, 'How to Plant the Three Sisters', gardening.cals.cornell.edu/lessons/curriculum-classics/the-three-sisters-exploring-an-iroquois-garden/how-to-plant-the-three-sisters (read 2026-07-11): 'When the corn plants are about 6 inches high, pole beans and pumpkins can be planted around the corn plants.'
USDA National Agricultural Library, 'The Three Sisters of Indigenous American Agriculture', nal.usda.gov/collections/stories/three-sisters (read 2026-07-11): 'Two or three weeks after the corn was planted, the women returned to plant bean seeds in the same hills.'