At least 4 m²43 ft². If your bed is smaller, the planner grays this plant team out, says why, and offers the nearest adaptation that fits. It never swaps in something else without telling you.
What it looks like planted
29 × Lettuce
29 × Corn
The real placement on an example 8 ft bed, the same layout the planner draws.
Between seasons
Nothing is left living in the bed over winter; the whole planting is re-established.
What it claims
The tall crop's midsummer shadow shelters the greens from the heat that makes them bolt
How it works: Leaf temperature. Shade from a taller crop lowers the leaf and soil temperature of the greens beneath it, and high summer temperature is the trigger that sends these species to seed and turns them bitter.
Evidence: checked against 5 sources in the research-based literature.
What a swap costs: A giant sunflower casts the shade, but its residue suppresses the small-seeded greens sown beside it; an indeterminate tomato needs a stake to stand that tall and is a heavy feeder. Neither needs the corn's pollination block.
If you skip this, the planting fails. The planner won’t allow it.
How it works: Maize is wind-pollinated and protandrous (each plant sheds its pollen before its own silks are ready). Tassels shed pollen that must land on the silks of neighboring plants. In a single row much of the pollen blows out of the row, and each silk it misses is one missing kernel.
Evidence: checked against 5 sources in the research-based literature.
Always plant corn in blocks of at least four rows. Corn planted in a single row will have much of its pollen blown out of the row, and will produce ears that have blank areas where kernels did not form.
This crop is wind-pollinated; therefore, plant in blocks of several rows rather than 1 or 2 long rows to ensure full ears.
richmond.ces.ncsu.edu
Glass Gem CornNC State Extension, Richmond County Center
When tassels start dropping pollen, stalks can be gently shaken. This mimics wind and will release the pollen to float down to the silks.
Remedy
Plant corn in a block of several short rows rather than one long row; four rows is best. For a small patch, shake the stalks gently while the tassels shed pollen, or dust a cut tassel over the silks, every few days. Or leave corn out and give the beans a trellis.
If you skip this, you lose real yield. The planner warns you.
How it works: Soilborne inoculum and overwintering pest stages disperse across the bed. A plant team dominated by one family forecloses that ground for that family's rotation interval.
Evidence: checked against 2 sources in the research-based literature.
Remedy
Rotate the whole bed the plant team occupied, including rows that family never grew in.
A new combination: the extension advice to plant long-season lettuce where sweet corn or staked tomatoes shade it in the hottest part of the day (University of Maryland, 'Growing Lettuce in a Home Garden'; NC State Extension Gardener Handbook ch. 16), laid out as one bed.
