coffee grounds & blight
I have a small raised bed asparagus patch and a separate 10 ftx10ft tomato area. Both of which I haven applying used coffee grounds to. My question is, what further should I do to encourage healthy productive plants and control blight?
Your best bet is do get a soil test done. They are relatively inexpensive and will give you the information that you need to improve your soil fertility, which will encourage the productivity and vigor of your plants.
Here is a link on soil testing, including how to do take a sample, and a link of regional labs which can complete the analysis for you: https://extension.umd.edu/hgic/soils/soil-testing
Your coffee grounds are an ok addition, but not terribly effective.
Any time you can work in generous amounts organic materials like compost, aged manure, shredded leaves, Leaf-Gro, etc., it's a good thing.
Not sure what you mean by 'blight', but here is our page on early blight, which is the most common, but manageable disease for our tomatoes: https://extension.umd.edu/learn/early-blight-tomato. As you will see, choosing resistant varieties, bringing home clean plants, planting with good air flow, mulching and sanitation, or cleaning up any remaining leaves or plant residues from the garden will help.
Here too is probably our most used tomato publication each summer, and that is IPM:Tomatoes, which lists photos,symptoms and strategies to deal with many common problems this beloved Maryland crop has: http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG56%20IPM%20Tomatoe...