In archaeology we use a grapefruit knife for fine intricate excavation work, and as a gardener I found these work great for getting under a seedling without damaging the roots. The grapefruit knife seems to have disappeared from stores lately, but it used to be found wherever food preparation tools were sold. It has a bent tip, serrated edge blade. This is a double bladed one, but a single bladed grapefruit knife was more common.
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