Archives

Archives are created automatically from Content Types and Taxonomies. eg; There are archives for the Content Type of Plantings. Plantings have the taxonoy of Plant Types for which there are Archives like all things Brassica. Field Notes has a taxonomy called Problems for which there are archive pages for. There are two types of taxonimies, Categories and Tags. Categories have a hierarchy(Brassica > Tatsoi) while Tags are free form and not hierarchical.

Here are some archive pages from the above examples. (the below links will open in a new tab/window and take you to the demo site)
Plantings (Plantings Content Type)
Brassica (Parent Plant Type Hierarchical Taxonomy)
Tatsoi (Child Plant Type Hierarchical Taxonomy)
Cabbage Worms (Problems Hierarchical Taxonomy)
Tunnel (Tag Taxonomy)

In the case of Cabbage Worms, it could have child Problems of certain types of cabbage worms like Cabbage Worms > Yellow Striped Cabbage Worm

Likewise with diseases. You could have Fungi > Fusarium Wilt (caused by a fungus)

This very much follows scientific taxonomies but you can use them however you want. You could have Tomato > Paste Tomatoes > Roma OR you could have Nightshade > Tomato > Early Girl. You could even start with Hardy as a parent level and Peas as a child.

The system is flexible enough to build it in the same terms you already use and think.