Dear Jeni,

Thank you for contacting us about your vegetables. All of them look like they are deficient in one or more nutrients. Have you had a soil test? This is the best way to determine what is in your soil and get advice about which nutrients are needed and very importantly, how much. We recommend a laboratory test when starting a new garden to set a baseline for amendments and fertilization.

I hesitate to recommend fertilizing without the benefit of a soil test because your soil seems to be seriously deficient in plant nutrients and/or the soil pH may not be appropriate. Undernourished plants are more susceptible to pests and diseases. However, if you choose to forego a soil test, you can use a fertilizer formulated for vegetables, and apply it exactly as directed on the label.

OSU Extension does not offer soil testing services, however, here is some information that may be helpful: 

• https://www.simplysoiltesting.com/
• https://catalog.extension.oregonstate.edu/ec628
• https://catalog.extension.oregonstate.edu/em8677
• https://catalog.extension.oregonstate.edu/ec1478

With regards to your cucumbers, cucurbits are very susceptible to powdery mildew. Powdery mildew can generally be avoided by planting resistant varieties, planting in full sun, and ensuring adequate air circulation around and through plants. Sprays are available, but given the stressed condition of your plants, I would suggest avoiding chemicals.

Here is a comprehensive guide for home gardeners that may help you:
https://extension.oregonstate.edu/catalog/pub/em-9027-growing-your-own

I hope this information is useful. Please write again if you have more questions.