Selective pruning is how to maintain good air circulation. But, when the humidity drops, the spores spread. Pruning has the advantage of contributing to humidity control and that is what is needed to control powdery mildew. Once the plants mature and the canopy closes later in the season is when the difference is noticeable.

The spacing for cucumber seedlings is one seedling for every sixteen inches. However, once the seedlings emerge and reach about 4-inches in height, they need thinning to prevent crowding.Ĭrowding reduces airflow, which encourages powdery mildew disease. When planting cucumber seeds, six-inch spacing is ideal. The spacing requirements change between seed planting and seedlings. At least three to four feet between rows. These should be grown with trellis support that is at least six feet tall.įor bush varieties, those need a lot more space. Plant with enough space between cucumbers to allow good airflowĬucumber vining varieties need support to climb. The exact environment for powdery mildew to thrive. In nurseries, seed germination is done in commercial greenhouses. When to pay more attention to disease resistance is when buying cucumber seedlings. That abbreviation means the cultivar is resistant to powdery mildew. The magical letters you want to see on your seed packets, or the online description of the seeds you are about to order are “PM”. Frequently Asked Questions related to white spots on cucumber leaves?.Treating white spots on cucumber leaves.Plant with enough space between cucumbers to allow good airflow.

Mmd raycast white spots