A culinary bundle - grown together for the kitchen, with no interspecies claim made.
Chosen for the kitchen. No interspecies mechanism — a co-harvest for the pickling crock: cucumbers and dill with garlic and onion, and beets for a second jar. They share a bed because they share a recipe.
At least 1.5 m²16.1 ft². A bed smaller than that does not get this guild quietly substituted for something else — the planner greys it out, says why, and offers the nearest adaptation that does fit.
Nothing is left living in the bed over winter; the whole planting is re-established.
No interspecies mechanism is claimed. It is grouped for a reason, and that reason is written below rather than dressed up as biology.
Rotation history attaches to the ground, not the bed, so this is what the planner remembers about this patch after the guild comes out.
This is a claim the planner refuses to enforce — recorded here with what is actually known, rather than dropped.
What is actually known: A guild asserts a mechanism between its members. A culinary bundle asserts only that you will want these things in the same bowl. Both are legitimate. Only one is a polyculture.
Evidence: settled without a trial - definition.
Mechanism: Soilborne inoculum and overwintering pest stages disperse across the bed. A guild dominated by one family forecloses that ground for that family's rotation interval.
Evidence: confirmed against 2 sources in the research-based literature.
Same soilborne-persistence basis as other rules here (read 2026-07-11): NC State Extension (Verticillium microsclerotia 'can survive in the soil without a host for up to 10 years'; Septoria/early blight 'overwinter on infected tomato debris and solanaceous weed hosts') and UMN/Ohioline (squash bug overwinters 'as adults in sheltered places ... they fly to growing cucurbit plants'; squash vine borer 'overwinters in the soil as a pupa').
Those sources establish that inoculum and pest stages persist in the ground and are not confined to the exact spot a plant occupied; this rule applies that persistence across the whole guild footprint. The whole-footprint attribution is the corpus's rotation geometry (history attaches to ground, not to the individual plant — see the data model), not a claim from an external source.
Rotate the whole bed the guild occupied, not just the rows that family grew in.
Mechanism: Bulbing fires when daylength crosses a cultivar's critical threshold (short ~10-12h, intermediate ~12-14h, long ~14-16h). A short-day cultivar grown too far north crosses its low threshold early and bulbs prematurely on small plants, so bulbs stay small. A long-day cultivar grown too far south never reaches its high threshold and fails to bulb. Changeover is around the 35th-38th parallel.
Evidence: confirmed against 2 sources in the research-based literature.
NC State Extension, 'Bulb Onions', content.ces.ncsu.edu/bulb-onions (read 2026-07-11): 'onions will not form bulbs until daylength reaches the cultivar's critical threshold. Short-day onions bulb at approximately 10-12 hours of daylength ... Intermediate-day onions bulb at approximately 12-14 hours ... Long-day onions bulb at 14-16 hours of daylength.'
Univ. of Illinois Extension (The Humble Gardener), 'Growing Onions in Central Illinois', extension.illinois.edu/blogs/humble-gardener/2018-03-19-growing-onions-central-illinois (read 2026-07-11): 'Long day varieties are for northern growing areas (above the 35th latitude); short-day varieties are for southern. If short-day varieties are grown in our zone, they won't do well. They will not form bulbs of any decent size. And since the long day onions need more daylight, they will not do well' (in the south).
Choose long-day onions in the north and short-day in the south; the planner picks the group from your plot's latitude.
