Hi, I'm Calum

I found gardening during covid, like half the country. What I couldn't find was a straight answer to the only question that matters: when do I actually plant this?

The seed packet said one thing. Google said another. A forum post from 2011 said something else entirely. So I hedged my bets, sowed everything early, and ended up with twenty tomato plants in the front room because it was still too cold to put them outside. My wife was not impressed.

When to Plant is the site I wished had existed back then. I built it, I run it, and yes, I still grow too many tomatoes.

Why the site works the way it does

The problem with most planting advice is that it's written for the whole country at once. The UK doesn't work like that. The last frost in Cornwall can be weeks earlier than in the Scottish Borders, and even towns fairly close together can have surprisingly different growing seasons. A calendar that's right for someone three counties away can be wrong for you.

So this site works the other way round. Pick your town and everything here, sowing dates, transplanting windows, harvest estimates, is worked out from the climate where you actually garden.

Where the dates come from

The frost dates behind the site come from the Met Office's HadUK-Grid dataset, which records observed UK climate going back decades. For each town I look at 30 years of real frost history and work out when the last spring frost and first autumn frost typically fall. Every plant's schedule is then built around those dates and what that particular plant can put up with.

An honest note: these are averages, not promises. Nature doesn't read calendars, and a rogue frost in late May can still flatten your courgettes. Treat the dates as a well-informed starting point, keep an eye on the forecast, and harden things off properly. That's gardening.