Olutil stands for Online Utilities — a growing suite of privacy-first, browser-native web tools. This sub-site brings you a complete set of plant and garden calculators that run entirely in your browser. Plan watering, spacing, soil, fertilizing and more — all in one place. 100% Local Processing
Build a 4-week watering calendar for your plants from pot, light and season.
Find out how often to water a specific plant based on pot size, season and light.
Check whether a spot in your home gives a plant the light level it needs.
Plan a monthly feeding schedule with dilution ratios for the growing season.
Work out correct spacing and how many plants fit in a bed or row.
Look up germination days and ideal temperature for common seeds.
Calculate peat, perlite and compost volumes for your pot size.
Decide whether a plant needs repotting and what pot size to use next.
Check whether two plants grow well together and why.
Lay out a grid plan for beds and count how many plants fit.
Count back from your last frost date to find the best sowing day.
Find typical spring and autumn frost dates for your region.
Look up the USDA hardiness zone for a ZIP code or city.
Estimate the harvest window from your sowing date and variety.
Calculate pot volume in litres or gallons and the soil needed.
Estimate mulch volume and bags from area and depth.
Check whether a plant is toxic to cats and dogs.
Diagnose common problems from symptoms with a local decision tree.
Work out nutrient amounts for a target EC or PPM.
Estimate daylight hours for a location today.
Keep a local growth log with a simple timeline.
Estimate weekly water use for your garden.
All tools on this site perform their work locally in your browser. Your data is never sent to any server, making these tools ideal for planning your own garden and plant care. Pick a tool, enter your details, click the run button and read the result.
Yes. All processing runs locally in your browser. Your data is not uploaded to any server. You can even use these tools while offline once the page is loaded.
No. Every tool works directly in your web browser using JavaScript. No plugins, extensions or software installation required.
No. The tools provide general horticultural guidance for planning only. Growing conditions vary by location, so always check your own plants and verify locally.
Explore our published in-depth care content: a plant encyclopedia, step-by-step care guides and month-by-month seasonal tasks — all live now.