The most consistently productive dry fly fishing of the spring season happens before the fish are rising. From the moment water temperatures begin climbing out of winter lows — typically in the upper 40s°F — trout shift from the tight, slow-metabolizing holding positions of winter into active feeding, and the first food they're eating in any quantity is nymphs. Not dries. Not emergers yet. Nymphs drifting along the substrate and through the water column, representing the full range of aquatic insect life that spring sets in motion.
The tyer who has a realistic, well-proportioned nymph in the box before the first significant hatch of the season — not after — is fishing when the eating is most reliable. Which is the argument for building a spring nymph bench now, with the right materials for each stage of the hatch calendar.
Semperfli's ABC range — Andy's Bugs and Creatures, developed by Andy Kitchener and laser-cut from synthetic suede — covers the freshwater spring spectrum from early-season BWO nymphs through the major stonefly migrations. Each body is water-reactive: the suede absorbs water on contact, activates subtle flex, and creates the kind of lifelike drift that segmented synthetic or dubbed bodies don't quite replicate. The porous surface accepts waterproof marker pens for colour-matching local insects, and a UV resin topcoat finishes the back into a durable, natural-looking shell. What follows is how to use the range across the spring calendar.
April and May: March Browns and Hendricksons
Hendricksons are among the first significant mayfly hatches across much of the eastern and midwestern United States, beginning as early as April and running through mid-May. They emerge in faster water and float for quite a while until their wings dry — which means trout have extended feeding windows on ascending nymphs before surface activity begins, and nymph fishing in the riffles and runs leading into feeding lies can be exceptional.
March Browns are one of the larger spring mayflies — sizes 12–14 — hatching sporadically through early to mid-May in riffles, glides, and pocket water. Their size makes them a more substantial target than Baetis, and a realistic body makes a genuine difference when fish have time and visibility to inspect the fly.
The build: ABC Mayfly Nymph 20mm or 25mm on a size 12–14 hook, standard or jig. Hendrickson nymphs are reddish-brown with distinct segmentation — the suede body takes a warm brown marker cleanly, and the laser-cut segmentation provides the visual detail that traditionally built bodies require ribbing and body material to approximate. March Brown nymphs trend darker: olive-brown to chocolate brown. A sparse Scud & Boom Dubbing thorax, Synthetic Marabou tail fibres, UV resin back.
The ABC Mayfly Nymphs Kit covers multiple sizes across the mayfly nymph life stages — the most efficient entry point for tyers who want to cover the full spring mayfly calendar from small Baetis through larger Hendrickson and March Brown nymphs without buying separate packs for each size.
May and June: The Stonefly Migration
Stonefly nymph fishing is the most underutilised opportunity in spring trout fishing. During emergence, stonefly nymphs migrate en masse to the shoreline before crawling up through the waterline into adults — and this migration, which unfolds over days or weeks depending on the species, puts large numbers of stonefly nymphs in the drift and moving through the water column in ways that make them among the highest-calorie food available to trout before the adult stoneflies appear.
The ABC Stoneflies are laser-cut in the flattened, segmented profile that stonefly nymphs actually have — not the rounded, generalist profile of most dubbed stonefly patterns. The water-reactive synthetic suede body produces the subtle flexing movement of a nymph working across bottom cobble.
The build for Salmonfly and Golden Stone nymphs: ABC Stonefly body in the appropriate size on a size 4–8 3X long nymph hook or wide-gap jig hook. Colour with brown, black, or golden-tan marker depending on species. Add rubber leg fibres, a sparse dubbed thorax, and UV resin over the dorsal surface. Weight with lead wire wraps on the shank for deep-run dead drifts.
For Yellow Sallies and smaller species: Small stoneflies in sizes 14–18 begin hatching in late May. The smaller ABC Stonefly bodies in yellow-gold on size 14–16 hooks cover this range — same construction, lighter wire hook, fished in faster riffle water in the afternoon when Yellow Sallies are most active.
The ABC Stoneflies Kit covers multiple sizes for the range from Yellow Sallies through large Salmonfly nymphs.
Customisation: The Marker Pen Approach
The ABC range is designed around the premise that a precise colour match to local insects matters and that tyers are best positioned to know what their local Baetis nymph looks like compared to a river three states away. The suede surface accepts waterproof markers for colour-matching before finishing with UV resin.
The practical approach: tie bodies in natural suede, colour with markers at the vise or in the hand, finish with UV resin. A set of seven to ten colours )pale olive, BWO tan, dark brown, golden amber, black, cream, and rust) covers the full spring freshwater nymph palette. The UV resin coat seals the colour, creates natural sheen, and significantly increases body durability.
The ABC SemperSuede Fly Sheets provide the raw suede material in sheet form for tyers who want to cut their own body shapes — scud profiles, freshwater crab bodies, or specific regional insect shapes that the standard ABC body range doesn't cover. The same water activation, marker acceptance, and UV resin compatibility apply.
