Spinach is an acquired taste but if you love it it is worth canning.
I was given two six gallon pails of New Zealand spinach. It is beautiful with large green leaves, very clean and was grown in a green house.
I was skeptical at first and concerned it would come out mushy. To my surprise it came out delicious. Here is the process:
Throughly clean the leaves. Watch for bugs and slugs. Trim off all the stems. Cut the spinach into smaller pieces. To do this I grabbed a large bunch and ran a knife over it. Some people like to cut it with a pizza cutter. Put the sliced leaves into a large pot of boiling water and blanch for 9 minutes. Fill jars to one inch from rim and add water from the blanching water to the one inch mark. Burp the jars for air bubbles and wipe off the rims. Put lids and rings on as directed and pressure cook for 75 minutes for pints.
The jars are very green and full of chlorophyll.