Let's continue with the worm castings market. If you're raising earthworms, you're going to have tons of this highly valued fertilizer. Did you know that a 3x8x1 foot bed can produce 600 pounds of of worm castings? This poundage does not include any decomposed organic material that remains from the bedding. This castings/compost is called vermicompost, an excellent soil amendment.
You can separate out as much of the organic material as possible, leaving mostly castings, and sell for a higher price. Since it is concentrated and you can dry it somewhat, shipping is not a problem Or, simple bag up the old bedding after removing your worms and sell as-is locally to farmers and gardeners. The extra weight of vermicompost, however, would make shipping costs prohibitive.
Marketing Worm Castings
Sell your worm castings wholesale by the ton to nurseries and farmers, or realize a bigger profit and sell it bagged retail. Generally, you should bag up your pure worm castings in 5#, 10#, 20#, and 40# bags. The vermicompost can be sold in 40# bags or by the truck load.
Selling retail requires more work and time, like advertising and making individual transactions. But, since the profit is higher, you may want to investigate the possibility if you have plenty of help from the family.
Check out your area for nurseries, farmers, gardeners, local governments, etc. for future worm castings/vermicompost sales. Once your own lawn or garden is covered with it and thriving, you've got to get rid of it somehow. And get some cash back in return, of course.
Red Worms: Excellent composting worms for producing castings. Sell the worms for home worm compost bins.
European Nightcrawlers: Although not as productive as red worms, this tough, active worm still make tons of worm castings. And European nightcrawlers bring a premium price for bait.