Your yard at a glance
Weather & rain
—Up next
Recent activity
The log
Everything you've done to the yard — every entry editable, nothing locked in. That's deliberate: the top complaint about the big brand apps is entries you can't fix or delete.
| Date | What | Zone | Product / detail | Amount | Cost |
|---|
Measure your lawn
Find your address, then click around the edge of a section of turf to trace it. Close the shape and you'll get square footage — trace the front, back, and side yards separately so each can have its own grass and its own program.
Satellite tracing is a close estimate — far better than pacing it off, and plenty accurate for ordering seed and fertilizer. Imagery & labels © Esri & contributors; address lookup by Photon, Esri World Geocoding, Nominatim, and Zippopotam.us — all keyless. Street not on the map yet? Use Set house pin and tap your house — that sets your location for weather too. No tape measure? Enter square footage by hand under My Yard & Settings.
Your zones
Weather & rain
Rainfall is imported automatically for your location every time you open GrassLog. It's weather-model data for your area — good, but not a gauge on your fence. If your rain gauge disagrees, correct any day and your correction wins.
Rainfall — last 14 days
7-day forecast
Water balance
Rain in minus what the lawn loses to evapotranspiration (ET₀). A negative week means the lawn is thirsty even if it rained once.
Weather data: Open-Meteo (free, no account, CC BY 4.0). Rainfall is grid/model data at roughly 1–11 km resolution, not a physical gauge at your house — hence the correction buttons. US severe-weather and frost alerts: National Weather Service.
Rate calculator & nitrogen budget
Tell it your lawn size and what's on the bag; it tells you exactly how many pounds to spread — and keeps a running total of nitrogen for the year against your grass type's budget. Only one paid competitor does this. Here it's free.
How much product do I need?
Math: lb of product = (area ÷ 1,000) × target N rate ÷ (N% ÷ 100). Example check: 5,000 sq ft at 1 lb N/1,000 with 32% N → 15.6 lb.
Nitrogen budget — this year
Logged fertilizer entries with a product amount and %N feed these bars automatically.
Annual nitrogen guides (lb N / 1,000 sq ft / yr): Kentucky bluegrass 3–5 · tall fescue 2–4 · bermuda 4–6 · zoysia 2–4 · St. Augustine 4–5 · centipede 0.5–2. Source: LandscapeCalculator fertilizer guide, via GrassLog market research, Oct 2026.
Tank-mix calculator — what goes in the sprayer?
The rate calculator above tells you how much product the lawn needs. This one tells you how to mix it: how much product and water per tankful, and how many tanks the job takes — including the partial last tank.
Math: total water = (area ÷ 1,000) × water per 1,000. Total product = (area ÷ 1,000) × label rate. One full tank covers (tank size ÷ water per 1,000) × 1,000 sq ft, so product per tank = label rate × (tank size ÷ water per 1,000). Always follow the product label — it wins over any calculator.
The shed
What's on your shelf, what you paid, and the price that would make you stock up.
Season program
Generated from your zones' grass types — warm-season and cool-season lawns get different calendars, and mixed yards get both. Timing leans on soil temperature, which is what actually drives pre-emergent windows.
Your program
Soil temp —Your own tasks
Pest control
Got bugs in the lawn? Work through it in three steps: figure out what's out there, treat it, then check whether it worked. Everything else on this page — the seasonal watch list, your notes from the yard, the spray-day weather check, and visits from a pest company — is here to help with those three steps.
Fix a lawn pest problem in 3 steps
What's the problem?
Walk the yard and look close — chewed or thinning grass, bugs just under the surface, dirt mounds. Jot down what you found and where; it turns the treatment into a decision instead of a guess.
What did you do?
Picked a product and put it down? Write it up while it's fresh — what you used, where, and what it cost. How much to use is always on the product's label; GrassLog just keeps the record.
Did it work?
About a week after a treatment, go look. Mark whether it worked, and GrassLog works out the earliest day you could treat again from the label details you saved.
Pests to watch for, by season
Timing only — amounts are on the labelBuilt from your grass types and where you live, so you only see the pests that actually show up in a yard like yours. When a pest's season is open, it may be time to look closer or treat. GrassLog tells you when — how much to use is always the product label's call. Pest products live in the Shed, in the “Pest / fungus” category.
Your treatments — and whether they worked
—Everything you've put down for lawn pests, what it cost — and the follow-up that closes the loop. A week or so after each treatment, mark the result; GrassLog then counts down to the earliest you could treat again and reminds you in the Alert Center.
What you've spotted in the yard
Your own notes from walking the yard — what you found, how many, how bad, exactly where, and a photo if you took one (handy for the extension office, or for comparing next season). Photos are shrunk before they're saved, so they stay small in your browser storage.
Is today a good day to spray or spread?
—Before you spray or spread, check the weather for your yard right now: the wind, the heat, how fast spray dries, and whether rain is on the way. Granular products actually want rain to wash them into the soil; baits and sprays want a dry stretch.
Home pest service
If a company treats your house instead, keep their visits here — who came, when, what they treated, and what it cost. Set the next visit date and the Alert Center reminds you as it approaches.
Advanced — timing triggers & product label details
The technical layer underneath the watch list and the “treat again” timing. You never need to open this to use Pest Control — it's here when you want to fine-tune the timing to your local extension office's advice, or check a treatment against the details on a product's label.
Season timing triggers
Each pest's season is timed by your yard's own soil temperature and accumulated warmth (growing degree days, base 50°F) — not just the calendar. Adjust a trigger if your extension office recommends different numbers for your area.
Label check
Your label details onlyPick a product whose label details you've copied into its Shed card — the most times it can be used in a year, the fewest days between uses, whether it needs watering in, and how long to keep off the lawn afterwards — and see where you stand against them. GrassLog never invents label values: a product with no details entered shows none, and the fields on the Shed card start blank.
Weed ID guide
A visual library — no photos to upload, no AI. Filter by what you actually see in the yard and narrow the list down to a match. The library only shows weeds that grow in your region, taken from your saved yard's location.
Your region
—Filter by what you see
Not sure about one? Leave it on “Any” — every filter you do set cuts the list. Start with leaf shape and growth habit; they're the two most reliable tells.
Identification is by visible traits only — if two weeds still look alike after filtering, part the leaves and check the stem and roots against both entries, or take a sample to your local extension office for a certain ID before treating. Treatment notes here are timing only; how much to apply is always the product label's call.
Application alerts
Due dates computed from your zones, your season program, and your own tasks — pre-emergent windows, planned fertilizer and treatments, and jobs coming due. Smart weather alerts watch the data GrassLog already imports: soil temperature entering the 50–55°F pre-emergent band, significant rain in the next 48 hours while an application is planned, and a weekly water-balance deficit. In-app and browser alerts work today, and the email digest works today too: one tap opens your mail app with the whole due list pre-filled. Automatic scheduled email switches on with the hosted mail service (see Settings).
Needs attention
—Coming up
How alerts work: this page checks your schedule every time you open it. Browser notifications pop at that moment for anything due inside your lead time — a static web page can't run in the background while it's closed, so keep the habit of a quick morning open — or use “Email me the due list” above to send yourself the whole list through your own mail app, which works today, no backend needed.
Soil tests
Lab results, kept year over year in one neutral place — no lab trying to sell you its own amendments. Enter values exactly as your lab reports them, units and method included; GrassLog tracks the trend, it doesn't force one scale.
| Date | Lab / source | Zone | pH | Phosphorus (P) | Potassium (K) | Units / method | Notes |
|---|
General reference only: most turf does best around pH 6.0–7.0 (centipede prefers 5.0–6.0). P and K scales vary by lab and extraction method (Mehlich-1, Mehlich-3, Bray, Olsen…), which is why your units/method are stored with every result — compare like with like, and let your lab's own recommendations lead.
Season report
Your season on one clean card — mows, applications, nitrogen, rainfall, and zones. Copy it as text, download it as an image, or print this view from your browser (the layout is print-clean) for the shed wall and the lawn forums.
The report includes only what's in your yard profile and log — name, location label, zones, and entries. Nothing else leaves your browser.
My yard & settings
Everything here lives only in this browser on this device — no account, no server, nothing sold. Export a backup file any time and import it on another device.
Yard profile
Zones
Your data
Entries, zones, shed items, and rain corrections are stored in this browser only. Clearing browser data erases them — keep a JSON backup of anything you care about.
Alerts & notifications
Reminders for applications and tasks coming due, computed from your zones, program, and tasks.
Honest fine print: this page runs entirely in your browser and cannot send email on a schedule by itself. Your address and preferences are saved here, ready to go — automatic email alerts switch on once the site's hosted email service is connected. Until then, the digest button above works any time, and in-app + browser alerts are fully live.
Support GrassLog
GrassLog is free, carries no ads, and pushes no products — the three things users of the big brand apps say they hate. If it earns its keep, the tip jar is how it stays that way. (Tip jars are also the one funding model that keeps the free weather data above fully legal — display ads would make it “commercial use.”)
Ko-fi takes 0% of tips; Buy Me a Coffee takes a flat 5%. Typical paid lawn apps charge $5–8/mo or $30–60/yr — a tip jar undercuts all of them.
Why GrassLog?
A neutral log that sells nothing: entries you can edit or delete, automatic rain you can correct by hand, mixed-grass zones in one profile, satellite measuring, and a nitrogen budget — free, with your data in your browser and exportable any time.