I like Miracle Gro potting soil. I've bought it the last couple of years, usually about $7 for ten pounds. I like it's "feel", nice and light, seems weed-free, and comes with three months of slow-release fertilizer built right in.

Depends on what kind of herbs you want to grow. A lot of culinary herbs like the soil on the lean side and the fertilizer in Miracle Gro would be too much. I like Supersoil... but that is just me.

My experience says 1 gallon of mature compost or composted manure + half a quart of sand. +50% sand for herbs like rosemary, marjoram and oregano, -50% sand for succulents like parsley, lovage and basil. It's a very rough measurement, but it works nicely.

I like FoxFarm's Ocean Forest potting soil. It's great as is outdoors, or cut 20% or so with perlite indoors.

You're right... never use chunky. Always go for light and fluffy.

Perfect homemade mix:

1/3 blended compost
1/3 peat moss
1/3 coarse vermiculite

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Container Gardening Medium