Teddy Mutterperl
The Person Behind SoilIQ

Hi, I'm Teddy.

I'm a solo developer based in Bergen County, New Jersey. I built SoilIQ because I couldn't find an app that told me what I actually needed to know about my soil — and I suspect I'm not the only one who's stood in a garden center trying to guess whether this weekend is actually the right time to plant.

It started with a lawn in Bergen County that refused to cooperate.

I'd overseeded every fall and every spring for two years. I was doing everything "right" — the right seed, the right fertilizer, the right watering schedule. The results were inconsistent in a way that made no sense on paper. Some patches would take beautifully. Others would sit dormant for weeks, then suddenly catch up, or not catch up at all.

The variable nobody was talking about was soil temperature. Grass seed doesn't germinate because it's October 1st — it germinates when the soil at seed depth crosses its threshold temperature, stays there, and accumulates enough heat. The calendar is a proxy for the soil. A rough one.

I started looking for an app that would just tell me the actual soil temperature at my location, at multiple depths, with a forecast. Something that could answer the question "is now a good time to seed, or should I wait five more days?" I couldn't find one that worked well. So I built it.

What started as a tool for my own lawn became something I shipped to the App Store. Then growers — real farmers and gardeners, not just lawn people — started using it and asking for more. More crops. More depth. More forecast. That feedback is what became SoilIQ 2.0.

One developer. No investors. No growth team. Just the product.

SoilIQ is not a VC-funded startup with a team of engineers optimizing for DAUs and engagement loops. It's one person building something genuinely useful and charging a fair price for the parts that cost money to run.

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Solo-built
Every line of Swift, every data model, every UI decision is mine. That means fast iteration and full accountability. If something is wrong, I fix it — there's no committee.
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No advertising
No ad networks, no tracking SDKs, no third-party analytics in the data path. The only analytics tool is Google Analytics on the website. The app itself collects no behavioral data.
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Model-first
The soil intelligence is built on real NWP science — ERA5-Land, thermal amplitude correction, precipitation cooling models — not just raw API data dressed up in a green theme.
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User-driven
Every major feature in v2.0 came from user feedback. When v1.3 shipped, three different users emailed asking for an Apple Watch app. v2.0 has one. PlantAI, the journal, probe calibration — same story.
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Fair pricing
Core features are free. Pro is $4.99/month or $29.99/year for unlimited saved locations — a feature that costs real money to build and maintain. No dark patterns, no artificial limits on core utility.
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Private by design
Your location never touches a SoilIQ server — coordinates go from your device directly to public API endpoints. No behavioral tracking, no ad SDKs. The underlying science is public and fully documented.

Where the numbers come from.

SoilIQ is built on three public scientific datasets — the same data that academic researchers and government agencies use. There are no proprietary sensors, no black-box algorithms, and no data that I can't tell you about.

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Open-Meteo — Forecast & Reanalysis
The primary data source. Open-Meteo blends ERA5-Land reanalysis with ECMWF IFS, NOAA GFS, and regional NWP model outputs to produce hourly soil temperature at four depths. SoilIQ fetches hourly data with a 3-day historical lookback and 14-day forecast horizon.
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ERA5-Land — Historical Archive (ECMWF)
For historical baseline data, SoilIQ uses the ERA5-Land archive — the European Centre for Medium-Range Weather Forecasts' high-resolution reanalysis dataset. This produces the 12-month climatological averages that power the "warmer than usual" contextual annotations and the soil health trend chart.
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ISRIC SoilGrids v2.0 — Soil Texture
Sand and clay fractions for your specific location come from ISRIC's SoilGrids v2.0 — a global soil information database maintained by the International Soil Reference and Information Centre. This feeds SoilIQ's Soil Thermal Amplitude Correction, which adjusts diurnal temperature swings based on actual local soil texture rather than assuming a generic loam.
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Apple CoreLocation — GPS Coordinates
Location data comes from your device's GPS via Apple CoreLocation. SoilIQ uses your coordinates to hit the above APIs and then caches results locally. The app does not transmit your location to any SoilIQ server — coordinates go directly from your device to the public API endpoints.

Where the project is going.

SoilIQ isn't a side project I'll abandon when I get bored. It's a product I use myself, every season. Here's what's already shipped and what's planned.

v1.0 → v1.3 — Web-wrapped MVP

Four-depth soil temperature, Open-Meteo integration, NWP artifact correction, precipitation cooling model, basic widgets. Proven the concept, found the audience.

v2.0 — Ground-up Native Rebuild

Full SwiftUI rewrite. PlantAI with 133 crops, 14-day forecast, three-tier frost alerts, Apple Watch app, Live Activity, home screen widgets, iPad support, soil journal, probe calibration, Soil Health Score, GDD tracking.

Android — Planned for 2027

The most-requested feature from people who don't have iPhones. SoilIQ will come to Android. The data model is platform-agnostic; it's a matter of building the native UI.

Expanded Crop Database — 2026 onward

133 crops is a good start. There are hundreds more — specialty vegetables, fruit trees, cover crop mixes, turfgrass varieties — that deserve their own data. Ongoing, each release.

International Expansion — 2027–2028

SoilIQ already works anywhere Open-Meteo covers, which is global. But the crops, planting guidance, and UX are built around North American growing conditions. Proper international support means localization, regional crop databases, and growing season logic.

Deeper Soil Science — Longer horizon

Nutrient availability windows, soil respiration modeling, mycorrhizal activity indicators — soil biology matters as much as temperature. This is a multi-year research project as much as an engineering one.

Questions, feedback, or a great feature idea?

I read every email and reply within 24 hours, usually faster. Feature requests go into the same backlog that produced PlantAI, the Watch app, and probe calibration. If you've found a bug or have a thought, reach out directly.