Summer challenges

I'd been forgetting that rain will leach the nitrogen out of your soil:

Nitrogen is quite water soluble so the endless days of rain have probably leached most of the available nitrogen out of your garden soil.

But this strikes me as a crazy way to test for nitrogen availability:

The easiest way to see if your plants need nitrogen is to pay attention to their leaf color. Get used to what is normal for your plants and when they start to turn a more yellowish or pale green chances are good they could use a boost of nitrogen.

When your plants are yellow, they are on the way out!

Link: The Press Republican - Summer challenges.