Sweet Corn Companion Planting

Pole beans fix atmospheric N2 via Rhizobium symbiosis, providing 20-60 kg N/ha that benefits nitrogen-demanding corn. Corn stalks serve as a living trellis for beans, eliminating the need for staking.

Plant corn first and allow it to reach 15 cm before sowing beans. Use sturdy corn varieties like Oaxacan Green or Painted Mountain.

Bush beans fix nitrogen that supplements corn fertility. While they do not climb corn, they function as a nitrogen-contributing understory. Bush types are easier to manage than pole beans in the intercrop.

Sow bush beans 2-3 weeks after corn to avoid competition during corn establishment.

Squash vines act as living mulch beneath corn, suppressing weeds and conserving soil moisture. Prickly squash foliage and stems may deter mammalian herbivores from accessing corn.

Both are heavy feeders. Prepare beds with compost. Space generously.

Same Three Sisters dynamic as winter squash-corn. Pumpkin vines shade ground beneath corn, suppressing weeds and conserving soil moisture. Corn provides vertical structure without shading the sprawling pumpkins.

Space generously. Both are heavy feeders requiring rich soil and consistent moisture.

Sunflowers on bed borders attract pollinators and predatory insects. They also function as a windbreak, reducing corn lodging in exposed sites. Both are tall warm-season crops with compatible growth habits.

Plant sunflowers on the north side of corn to avoid shading. Use as border or windbreak.

Crimson clover (Trifolium incarnatum) fixes 70-150 lb N/acre when used as a winter cover crop before corn. Spring incorporation releases plant-available nitrogen that reduces or eliminates supplemental N needs.

Sow crimson clover in fall, incorporate in spring before corn planting. Timing of incorporation affects N availability.

Sweet potato vines function as living mulch beneath corn, suppressing weeds and conserving soil moisture. Corn provides vertical structure without shading the low-growing sweet potato.

Both are warm-season, heavy-feeding crops. Prepare beds with ample compost.

Watermelon vines function as living mulch beneath corn, suppressing weeds. Corn provides vertical structure. Same spatial complementarity as the Three Sisters system.

Both are heavy feeders requiring rich soil. Give watermelon vines 2-3 meters of spread room.

Lima beans fix atmospheric nitrogen via Rhizobium symbiosis, providing soil nitrogen for heavy-feeding corn. Same nitrogen-sharing mechanism documented in the Three Sisters system.

Lima beans are slower-maturing than bush beans. Plant with adequate growing season.

Edamame (Glycine max) fixes substantial nitrogen via Bradyrhizobium symbiosis that benefits adjacent corn. Soybean intercropping with corn is one of the most extensively studied intercropping systems globally.

Edamame requires inoculation with Bradyrhizobium japonicum if not previously grown in the soil.