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.
How it works: The flowers supply nectar and pollen that adult predators and parasitoids feed on, so a patch of them near a fruiting crop keeps those beneficial insects fed and close by to work the crop. The effect is real but not guaranteed. An insectary patch does not always suppress pests.
Evidence: checked against 1 source in the research-based literature.
Insectary plants are those grown to attract, feed, and shelter insect parasites (parasitoids) and predators to enhance biological pest control. Insectary plants provide nectar and pollen, which the adults of many natural enemy species need to consume.
Who does what, and the swaps
Each job in this planting can be done by more than one plant. The usual choice comes first, and each swap says what it costs.
What a swap costs: A sunflower feeds natural enemies from its extrafloral nectaries as well as from its flowers, and it pays for that twice here: it is a heavy nitrogen feeder set among corn that is already one, and it casts shade over the mounds the squash and beans are working. Borage carries neither cost - it stays short and casts none.
What it costs the ground
Rotation history belongs to the ground itself, so this is what the planner records about this patch after the plant team comes out.
Grasses: counts as a full season of this family
Legumes: counts as a full season of this family
Cucurbits: counts as a full season of this family
Rules that decide where it fits
Corn needs a block of at least three short rows side by side for good kernel set, and four rows is better.
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.
