Ecoworm Potassium Soap | Organic Pest Spray & Garden Cleaner

If you garden organically (or want to), Ecoworm Potassium Soap is one of the most properly useful sprays you can have on the potting shelf. A genuinely effective natural treatment for the soft-bodied pests every gardener meets — aphids, whitefly, red spider mite, scale insects, caterpillars, sawfly larvae — made from sunflower-oil-derived potassium salts, fully biodegradable, and certified organic by the Organic Farmers & Growers (OF&G). Safe for edibles, bees and ladybirds when used properly. The everyday spray that lets you actually control pests without resorting to chemicals you'd rather not have anywhere near your salad bowl.

From Ecoworm, the Irish-based eco-pest-control specialists. We stock their potassium soap because it does the job properly — not just "eco-marketed", but genuinely tested, OF&G certified, and trusted across the organic gardening community.

What it actually does

Potassium soap works mechanically, not chemically. When sprayed on soft-bodied pests, the soap dissolves their protective waxy cuticle and disrupts their cell membranes — the pest dehydrates and dies. Because it relies on physical contact rather than chemical poison, there's no toxic residue left on the plant, no long-term soil contamination, and no withholding period of weeks before you can eat your produce. It's the proper way to do everyday pest control in an edible garden.

What it tackles:

• Aphids — the workhorse use; greenfly, blackfly, the classic spring rose and broad-bean pest
• Whitefly — particularly the greenhouse menace on tomatoes, peppers, brassicas
• Red spider mite — the dry-air greenhouse pest that turns leaves stippled and dusty
• Scale insects — the small armoured pests on bay, citrus, and houseplants
• Woolly aphids — the cottony white masses on apple trees, beech and elder
• Caterpillars — the smaller ones; cabbage white, sawfly larvae, gooseberry sawfly
• Earwigs — on dahlias, clematis, and similar
• Mealybugs — the cottony houseplant and greenhouse pest

Effective only against soft-bodied pests — hard-shelled beetles (vine weevil adults, ground beetles) and the larger thicker-skinned pests aren't affected. For those, biological controls (like our Ladybird Plant Care nematodes) or physical methods work better.

Why it's properly organic-garden friendly

• OF&G certified organic — the leading UK organic certification. Means you can use it on certified-organic plots without breaking the rules
• Plant-based ingredients — sunflower oil potassium salts, nothing synthetic
• Fully biodegradable — breaks down completely; no soil residue, no water-system contamination
• Safe for ladybirds, bees and other beneficials when applied correctly — spray in early morning or evening when pollinators aren't active; avoid spraying directly on flowers in bloom
• No withdrawal period for toxicity reasons — the 5-day pre-harvest interval is best-practice rinsing time, not because the product is dangerous. You can safely eat treated plants once any visible residue is rinsed off
• Provides secondary potassium — the potassium content gives a small nutrient boost to the plant; modest but genuine
• No build-up of resistance — because it works by physical action, pests can't evolve resistance to it the way they do to chemical insecticides

Two ways to buy

Two variants for two kinds of use:

• Spray bottle 500ml ready-to-use — £14.00. Pre-diluted, fitted with a sprayer, ready to grab off the shelf and use immediately. The right choice for occasional use, smaller gardens, or houseplants. No mixing, no measuring, no hassle
• Concentrated bottle 1L — £15.00. Dilute 200–600ml per 10L of water depending on pest severity. Works out significantly cheaper per litre of usable spray (1L of concentrate makes 17–50L of working solution), and the right choice for serious vegetable gardens, allotments, fruit cages, or anyone doing regular preventive applications

For most home gardeners, the 500ml ready-to-use is the starting point. If you find yourself using it regularly through the growing season, switch to the 1L concentrate — significantly better value for active gardeners.

How to use it properly

For preventive care:

• Spray every two weeks through the active growing season (April-October), particularly before known pest pressure periods
• Spray both sides of the leaves and stems, until the surfaces are just wet (not dripping)
• Apply from about 30cm distance for even coverage

When pests appear:

• Spray 3–4 times, one day apart, or as needed to reduce the infestation
• Repeat the treatment cycle 8–10 days later if the pest population recovers
• Ensure thorough coverage — the soap only works on contact; pests it doesn't touch survive

Timing:

• Spray in early morning, evening, or on cloudy days — avoid direct sunlight, which can cause leaf scorch on wet foliage
• Avoid spraying in windy or rainy weather — coverage is poor, and rain will wash the soap off before it works
• Allow a 5-day interval before harvesting treated edible plants (best practice; not toxicity-based)

Don'ts:

• Don't spray directly on open flowers, fruit, or berries — the soap will damage flower tissue and leave residue on edibles
• Don't spray when bees and other pollinators are active — the soap is mostly safe but direct contact during application can affect them
• Don't use on very young or stressed plants at full strength — dilute further if applying to seedlings
• Don't expect it to work on hard-shelled pests — it's for soft-bodied insects only

The double use as garden cleaner

One of the more useful surprises about potassium soap is that it doubles as a properly effective natural cleaner for the garden:

• Greenhouse glass and frames — removes algae, sooty mould, and the accumulated grime of a season. Use diluted; sponge or spray onto surfaces, leave 1–3 minutes, rinse off
• Garden tools — cleans spades, trowels, secateurs without harsh chemicals
• Plant pots and containers — removes white limescale deposits and accumulated grime from terracotta and plastic
• Polytunnel surfaces
• Garden furniture — gentle on wood, effective on grime
• Leaves themselves — gently removes sooty mould (the black fungus that grows on honeydew left by aphids and whitefly)

One bottle, multiple uses. Good value for an organic gardener's shelf.

Where it fits in our organic gardening range

Potassium soap is one of the key pieces of our organic pest control approach — alongside biological controls, pollinator support, and integrated pest management (IPM). The complete picture:

• Soil pests (vine weevil larvae, chafer grubs, codling moth, ants) — controlled by our Ladybird Plant Care biological nematodes
• Soft-bodied above-ground pests (aphids, whitefly, mites, scale) — Ecoworm Potassium Soap (this)
• Slug and snail prevention — encouraging birds (with our ChapelWood feeding stations) and frogs (with a small pond or boggy corner)
• Pollinator support — planting pollinator forage (Plants for Pollinators range) and providing water (our Decorative Bee Drinker Cuppy)
• Healthy soil — peat-free organic composts from Dandy's, plus the natural fertility of comfrey and borage

Together, these form a properly integrated organic gardening approach — pollinators encouraged, beneficials protected, soft-bodied pests controlled without chemicals, soil pests managed biologically, and birds and frogs welcomed as natural allies.

Specifications

• Brand: Ecoworm
• Type: Horticultural potassium soap (insecticidal soap)
• Active ingredient: Potassium salts of fatty acids (sunflower oil-derived)
• Certification: OF&G certified organic
• Variants:
  • Spray bottle 500ml ready-to-use — £14.00
  • Concentrated bottle 1L — £15.00
• Dilution (concentrate): 200–600ml per 10L water
• Pre-harvest interval: 5 days (best practice; not toxicity-based)
• Targets: Aphids, whitefly, red spider mite, scale insects, woolly aphids, caterpillars (small), sawfly larvae, earwigs, mealybugs
• Also use as: Garden tool cleaner, greenhouse surface cleaner, sooty mould remover

A small thought: organic gardening isn't about being purist or making things harder for yourself. It's about choosing the methods that work without leaving toxic residues on the things you eat or breathe in the things you spray. Potassium soap is one of those genuine equivalents to chemical pest control — works on the pests it claims to work on, doesn't leave a chemical fingerprint, doesn't accumulate in soil, doesn't harm the bees you've worked hard to attract. The grown-up choice for the cottage garden, the allotment, and the kitchen window-box. Keep a bottle on the shelf; you'll reach for it more often than you think.

Variant-dependent:
- 500ml ready-to-use spray bottle with sprayer
- OR 1L concentrate bottle (sprayer not included; dilute before use)

- Store in a cool dry place out of direct sunlight
- Keep away from children and pets (as with any garden chemical)
- Shake well before use
- Do not freeze
- Use within shelf life printed on bottle (typically 2-3 years from manufacture)