I have access to a substantial amount of non-organic lemon peels i was thinking i could compost them with leaves but am afraid that pesticide residues will contaminate the heap! Any knowledge or opinions would be great! Thanks
Fertilizer bags are labeled with their N-P-K content. (Nitrogen-Phosphorus-Potash = N-P-K)
For example, a fertilizer labeled "10-3-1" would be 10% nitrogen, 3% phosphorus, 1% potash.
A bag of lemon peel ashes would be labeled "0-6.3-31"
In most fertilizers, potash is the lowest number: it is relatively scarce, and expensive.
Most 'cides' will break down (somewhat) in composting...heat + exposure to oxygen.
The poisons can, however, kill off the critters needed to compost your pile. The higher concentration of poisons, the longer it will take to convert that biomass into something useful to your plants.
As I recall, my grandmother said citrus peels were good for the compost pile BUT you had to keep that compost longer than say traditional green scraps. Citrus peels take a little longer to decompose and so that may be why she said that. I am not sure of the pesticide factor on the peels but do know that until the peel begins to break down you do have some natural pesticide features happening in your compost pile. In fact as a child, I can recall my grandmother using citrus peels that she zested around areas she didn't want bugs to be. Please note I am going off of memories from 30+ years ago so some of the information may not be exact.
Insecticides which are approved for food products have a time limit in which they should be neutral...not sure if i said this right. The fda not only approves products but they also say things like end spraying 6 weeks before harvest.
Although never having had insectide on it is likely best, i think by the time the rinds compost the insecticides are long gone.
Though I cant find it now, I seem to remember a study about composting food scraps containing fruit peels which had been sprayed. The results showed nearly a third of the pesticides remained after the composting process.
If I was composting something I thought had pesticides on it I would mix it with a lot of Biochar and a lot of other materials in the compost pile, then feed it to worms, and would then test a bit by growing some seedlings from where I'm planning to put it in a 50% compost 50% soil mix.
I would think making Biochar out of the peels would be a good alternative, giving you a relatively clean, K rich soil amendment in the shortest time possible.
Good question Clarence! I don't know but I would be tempted to put the peels in a covered metal container and set it in a cook fire or wood stove. Much like how you can make charcoal in an existing fire. They should dry out pretty quickly and then burn down to charcoal.
Hopefully someone who actually knows comes along with a better answer