im a firm believer in egg shells,,i crush to powder some and others are for top dress,best method for banna peels is a 5 gal bucket out in direct sun light in same bucket,coffe,tea,lettuce,celery and all veggie scraps,after a week ready for some tea with 2 handfuls of compost,,my crushed to dust egg shells,,i build a circle about 3 in from stem and if you got slugs or snails trying to keep you from getting stoned or table fair,it cut um a new asshole,,they never make it to stem,,no scientist here,but all them goodies mixed together and brewed in my air lift system for 24 hours,bt the time i get done with the veggie garden and turn around to come out,every thing is praying to the sun