| Treatment | Fresh Bulb Weight (g) | RII | Interaction |
| Onion Control | 0.99 |
|
|
| Onion-Onion Above | 1.66 | 0.25 | Facilitative |
| Onion-Lettuce Above | 1.09 | 0.05 | Neutral |
| Onion-Onion Below | 1.45 | 0.19 | Facilitative |
| Onion-Lettuce Below | 0.59 | −0.25 | Competitive |
| Onion-Onion Both | 0.74 | −0.14 | Slightly Competitive |
| Onion-Lettuce Both | 0.45 | −0.38 | Competitive |