Free garden calculators for wiki

Hey everyone,

I'm a developer who built some free gardening tools that people can use without signing up or paying anything. I came across the wiki and thought they might be useful to add:

- Chill Hour Checker- checks if fruit trees will grow in your zip code
- Plant Spacing Calculator - for pots, containers, and raised beds
- Crop Timeline Calculator - sowing, transplanting, and harvest dates
- Companion Planting Checker - which vegetables grow well together
- Frost Date Finder - last spring and first autumn frost dates

They're all modern, mobile-friendly tools.
And if you have ideas for other tools that would be helpful, I'm happy to build them.

Thanks,
João