Niwaki Garden Snips (via Kew Shop)

The best sub-£20 gift for a plant nerd, and the standout value pick of this shortlist. Per the Kew Shop listing, these Niwaki snips are made in Sanjo, Japan from 5SK-85 steel, with 50mm slender blades, a 3mm maximum cut and a 91g weight — designed for green growth only (flowers, fruit, veg, herbs and soft stems), which is exactly houseplant snipping and propagation rather than woody pruning. They carry genuine craft credibility: Niwaki's related Okatsune snips were called 'terrific' by Gardeners' World, and the brand is stocked by the likes of Petersham Nurseries and twentytwentyone. The trade-off versus the picks above is scale — they're small, functional and near-universally useful, but they lack the visible 'wow' of a grow light, copper can or terrarium, which is why they sit as the value/stocking-filler tier rather than the headline gift.