Feed your soil
the natural way.
British BSF insect frass fertiliser — NPK-rich, chitin-active, microbially alive. The organic slow-release soil booster your garden has been waiting for.
The UK’s natural insect frass fertiliser, made from black soldier fly larvae
Flytiliser is our brand of insect frass fertiliser, produced as a natural by-product of our British black soldier fly farm. As our larvae process UK surplus food, they produce a granular material — the frass — that is exceptionally rich in plant-available nutrients and beneficial compounds.
Unlike most insect fertilisers on the market, which are made from beetle or mealworm frass, Flytiliser is made from black soldier fly (BSF) frass. A peer-reviewed study in Scientific Reports found that BSF frass has significantly higher nitrogen (N) and potassium (K) concentrations — up to 130% more N and 193% more K than frass from other insect species. That means Flytiliser is a genuinely superior product, not just a greener-sounding version of what’s already out there.
The result is a slow-release organic fertiliser with an NPK ratio of 3-1-3. It feeds plants steadily over weeks rather than giving a short spike and disappearing, which is what happens with most synthetic and many organic quick-release feeds.
Why chitin makes Flytiliser different
The nutrient profile is only part of the story. Flytiliser also contains chitin — a natural biopolymer found in insect exoskeletons. Chitin is what sets insect frass apart from every other organic fertiliser.
When chitin is applied to soil, plants interpret it as a signal that insect pests are nearby. In response, they ramp up their natural immune responses — thickening cell walls, producing more defensive compounds, and stimulating beneficial soil fungi. The result is more disease-resistant crops, improved root systems, and noticeably healthier plants without any chemical inputs.
Flytiliser is also microbially alive. It contains a diverse community of beneficial bacteria and fungi that improve root zone conditions, enhance nutrient uptake, and contribute to long-term soil health — the kind of soil biology that takes years to build naturally, accelerated by a single application.
Flytiliser nutrient profile
How to use Flytiliser
| Application | Rate |
|---|---|
| Raised beds & borders | 50–100g per m² |
| Containers & pots | 1–2 tsp per litre of compost |
| Lawn top dressing | 30–50g per m² |
| Houseplants | ½ tsp per pot monthly |
| Frequency | Every 4–6 weeks, growing season |
500g resealable bag treats up to 10m² of growing space. Free delivery on orders over £20.
Buy Flytiliser — £8.50From surplus food to soil gold — in one circular British farm
Flytiliser is not a manufactured product. It is what happens when you raise thousands of black soldier fly larvae on UK surplus food in a controlled British grow room. The frass is a natural by-product — collected, dried and bagged direct from our farm in Yoxall, Staffordshire.
Nothing is added. No synthetics, no binders, no fillers. Just concentrated insect output — and the natural compounds that come with it. The same larvae that produce Flytiliser also produce our Live Calci Worms for chickens, which means the entire operation is a genuine closed-loop circular economy: surplus food in, two valuable products out.
Read our sustainability story →UK surplus food collected
We source spent grain, food-grade surplus and organic waste from UK producers — diverting it from landfill.
BSF larvae are fed & grown
Black soldier fly larvae are incredibly efficient converters — turning organic waste into protein and frass in 7–10 days.
Frass is collected & dried
The frass — larvae castings and shed exoskeletons — is collected, heat-dried and screened to remove any unwanted material.
Bagged & dispatched from Staffordshire
Hand-bagged in 500g resealable pouches and sent direct from our farm. No middlemen, no distribution centres.
Works on every growing space — indoors and out.
Vegetable gardens & allotments
Apply at 50–100g/m² before planting or as a season top dressing. Particularly effective on brassicas, courgettes, tomatoes and root vegetables.
Containers & raised beds
Mix 1–2 teaspoons per litre into compost before potting. The slow-release profile is ideal for containers where nutrients leach quickly.
Houseplants
Half a teaspoon top-dressed monthly during growing season. Safe for all houseplants — no risk of burning roots even at higher rates.
Lawns & flower borders
Scatter 30–50g/m² and rake in lightly. The chitin content helps activate soil biology and supports a healthier lawn ecosystem naturally.
BSF frass outperforms beetle and mealworm frass on the nutrients that matter.
| Feature | Flytiliser (Syntects) | Ecothrive Charge | Wiggly Wigglers Frass |
|---|---|---|---|
| Insect source | Black soldier fly (BSF) | Beetle larvae | Mealworms |
| NPK ratio | 3-1-3 | 3.5-2.5-2 | Not specified |
| N vs other frass | Highest N of all insect frass* | Lower N than BSF | Lower N than BSF |
| K vs other frass | Highest K of all insect frass* | Lower K than BSF | Lower K than BSF |
| Chitin content | ✓ Present | ✓ Present | ✓ Present |
| British-farmed | ✓ Yes — Staffordshire | Not specified | ✓ Yes — Herefordshire |
| Circular economy | ✓ By-product of Calci Worms | – | – |
| Price / 500g | £8.50 | ~£12–£15 | ~£9–£12 |
*Source: Tanga et al. (2022), Scientific Reports — “Nutrient quality and maturity status of frass fertilizer from nine edible insects.” BSF frass showed 20–130% higher N and 17–193% higher K than frass from other insect species.
What gardeners say about Flytiliser.
Used the Flytiliser on my raised beds this spring and the difference is remarkable. My tomatoes are the healthiest they’ve ever been. Good to support a genuinely British product too.
I’ve tried Ecothrive and a few others but this is better value and the fact it’s a genuine circular economy product (the frass is from their calci worm farm) actually convinced me to switch.
Ordered alongside the calci worms for our chickens. Brilliant concept — the worms’ waste becomes fertiliser for the allotment. Plants are loving it and arrives quickly from a UK address.
Ready to feed your soil?
- 500g resealable bag
- Treats up to 10m² of growing space
- BSF frass — highest NPK of all insect frass
- Chitin-active, microbially alive
- Zero synthetic inputs
- Made in Yoxall, Staffordshire
- Free delivery on orders over £20
Everything you need to know about insect frass fertiliser.
What is insect frass fertiliser?
Insect frass is the collective term for the waste products produced by insects during their larval stage — a combination of droppings (castings) and shed exoskeletons. When collected from a controlled insect farming operation, it forms a nutrient-rich, organic fertiliser. Flytiliser is made specifically from black soldier fly (BSF) frass, which scientific research has found to have the highest nitrogen and potassium content of any insect frass.
Is Flytiliser safe for all plants?
Yes. Flytiliser is gentle enough for even the most sensitive plants. It will not burn roots or foliage even at the higher end of recommended application rates. It is suitable for vegetables, fruit, flowers, lawns, houseplants, and all outdoor growing spaces.
How does Flytiliser compare to Ecothrive Charge?
Ecothrive Charge is made from beetle larvae frass (NPK approximately 3.5-2.5-2). Flytiliser is made from black soldier fly frass (NPK 3-1-3). While the phosphorus content is lower in Flytiliser, the scientific literature consistently shows BSF frass has significantly higher nitrogen and potassium than beetle or mealworm frass. Flytiliser is also priced at £8.50 per 500g compared to £12–£15 for the equivalent Ecothrive product.
How often should I apply Flytiliser?
Every 4–6 weeks during the growing season (typically March–October). Because it is slow-release, it continues feeding soil biology between applications. For a new growing area, a slightly heavier initial application — up to 150g/m² — can help establish a healthier soil biology baseline before you switch to regular maintenance rates.
Can I use Flytiliser alongside other fertilisers?
Yes. Flytiliser is particularly effective alongside liquid feeds or other organic inputs. It is not a quick-release feed — it builds soil biology over time. Many gardeners use Flytiliser as their background soil amendment and add a liquid feed during peak fruiting or flowering periods for an additional boost.
What is chitin and why does it matter?
Chitin is a natural biopolymer found in insect exoskeletons. When present in soil, plants detect it as a signal that insects are nearby and respond by activating their natural defence systems — thickening cell walls, producing protective compounds, and stimulating beneficial soil fungi. This makes plants noticeably more disease-resistant without any chemical input. Not all organic fertilisers contain chitin; it is unique to insect-derived products like Flytiliser.
How much does one bag treat?
A 500g bag treats approximately 5–10m² at standard application rates (50–100g/m²). For containers and pots, one bag will typically provide a full season of applications for 10–15 medium-sized pots. For houseplants at the half-teaspoon rate, a single bag can last well over a year.