I have some white just showing up along the edges of a couple of my cucumber leaves. It's been a few years since I last had cucumbers in this section of my gardens last couple it's been tomatoes or peppers (banana jalapeno, habanero, maybe green peppers. I've been extending the garden each year.  Part of where they are was lawn 2 years ago (or 3 or 4). Also you can't go real deep less then 2 feet down is like gravel then impossible to dig through clay like junk . But last year the tomato plants were at least 5 12-6 feet maybe more soooo.