Potato + Cucumber

Potato and cucumber are an antagonistic pairing. Grower experience and extension guidance indicate that cucumber plantings can increase late blight pressure on adjacent potato crops, making close proximity a liability in gardens where late blight is already a seasonal concern.

The practical rule is physical separation: keep at least 30 feet between these crops. In small plots where that gap is difficult to achieve, prioritize placing potato in the upwind or uphill position to reduce any shared disease load. Succession planting should also be avoided. Following cucumbers with potatoes, or potatoes with cucumbers, in the same bed carries the same risk as side-by-side plantings.

Soil compatibility is not the issue here. Both crops grow well in loose, well-drained, moderately fertile ground with similar water needs. The conflict is epidemiological, not horticultural. Most home gardens are compact enough that a 30-foot buffer is hard to maintain, which makes this a pairing worth routing to entirely separate sections of the plot.