Nutrients can also cause hollow cukes.
1. Excessive Nitrogen could be the cause. Nitrogen is great for the growth of lush foilage and long healthy looking vines. The fruit however, the cucumber itself, will grow quicker than the interior can form resulting in poor seed development and hollow cucumbers.
2. Low boron levels in the soil can also lead to hollow cucumbers. Although cucumbers require very little boron, they do require some. Boron is needed for seed and cell formation and fruit set as well as other factors. Boron being highly soluble is easily leached in some soil types, sandy soils in particular.
Inadequate pollination is the third reason for hollow cucumbers, it is frequently accompanied by fruit drop and misshapen and or deformed cucumbers. See: Why Cucumbers fall of the vine.
Cucumbers are not as easily pollinated as many of the vegetables we commonly grow. Their pollen is larger and tackier, hence wind alone is not sufficient to supply adequate pollination nor are the many fragile and delicate pollinators such as butterflies, honey bee activity or hand pollination may be needed.
Related Declining Bee Populations Cucumber Bacterial Wilt
Why Cucumbers Turn White Cucumber Insect Problems Cucumber Mosaic Virus