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Gnat Juice Recipe - Attract 'em | Trap 'em | Kill 'em
A simple, cheap bait solution that lures fungus gnats and fruit flies, then traps and drowns them before they find your grow.
Fungus gnats and fruit flies are tiny, persistent pests that can disrupt clean cultivation. This Gnat Juice recipe is fast to make, uses household ingredients, and works best when placed in short, wide-mouthed containers near where you’ve seen pests.
Ingredients
- Water — 1/2 cup
- Sugar — 1 Tablespoon
- Apple cider vinegar — 2 Tablespoons
- Dish soap — 6 drops
Tools
- Short, wide-mouthed containers (ramekins, jar lids, shallow cups)
- Spoon for stirring
Steps
- Combine 1/2 cup water, 1 Tbsp sugar, and 2 Tbsp apple cider vinegar. Stir until sugar fully dissolves.
- Add 6 drops of dish soap and stir gently to avoid excessive foaming. The soap breaks surface tension so pests sink.
- Pour into short, wide-mouthed containers.
Placement
- Set traps where you’ve seen gnats or flies: near trash, drains, houseplants, or the outer perimeter of your workspace.
- Keep traps outside sterile or positive-pressure areas if possible. The lure is for pests, not your clean room.
- For maximum catch, place several small traps instead of one large one.
Maintenance
- Check daily; replace when the surface is cluttered with insects, or every 2–3 days.
- Rinse containers with hot water and a little soap before refilling.
- Combine with good hygiene: remove organic debris, keep areas dry, and seal entry points.
FAQ
Can I use other vinegars?
Apple cider vinegar is most attractive to fruit flies and many gnats. White vinegar tends to be less effective.
Is this safe around a grow?
Use traps around the grow to intercept pests before they reach your clean area. Avoid scented soaps that could introduce fragrances; unscented works best.
What if I’m still seeing pests?
Use multiple traps, improve sanitation and airflow, and consider sealing gaps. For mushroom cultivation, keeping fruits sealed inside a Fruit-in-Bag Tek grow kit helps prevent exposure.