If you don’t want to accumulate dirt under your fingernails while you’re gardening, scratch a bar of soap before starting. The soap lodged under your nails will prevent soil from penetrating. When you finish in the garden, just use a nail brush to remove the soap and your nails will be perfectly clean.
Or even easier, just wear gardening gloves.
The Right Attitude
But most laidback solution of all is simply to wear your dirty fingernails with pride: you are a gardener and this is what a gardener’s fingernails look like! ‘Nuff said!