The Broccoli Planting Calendar is a free online tool that turns your last and first frost dates into a full broccoli season calendar, with indoor sowing, transplanting, direct sowing, and harvest dates. It runs entirely in your browser, so you do not need to install anything, create an account, or share your location with anyone. You open the page, enter your two frost dates, and get a full season calendar in seconds. Home gardeners often guess planting dates from memory, and this tool replaces that guesswork with dates you can check against your own climate.
It is made for home gardeners who grow broccoli and want dates fitted to their own climate. If you grow food at home, in a small garden, in raised beds, or in containers on a balcony, you already know that planting too early or too late can cost you a whole crop. A late frost can kill young plants, and a crop sown too late may never ripen before autumn. This calendar keeps those risks visible, so you can plan around your real frost dates instead of a generic month printed on a seed packet.
You start by entering your last spring frost date and your first autumn frost date. Your last spring frost date is the average date after which frost becomes unlikely in spring, and your first autumn frost date is the average date when frost returns in autumn. You can find both dates from your local weather service or a gardening almanac for your town. If you are unsure, use the average for your area and then keep a simple frost cover ready, because averages hide cold years.
Take this worked example: a last spring frost date of 15 April 2026 and a first autumn frost date of 15 October 2026. The tool shows a frost-free season of 183 days, a direct sowing window, and a harvest window for this crop. Notice how the answer is not just one date. It gives you a window for each step, because weather varies from year to year. A window lets you wait out a cold week or a wet spell without missing the season, and that flexibility is what makes a home garden plan work in real life.
The result matters because a sowing date alone does not tell you whether the crop will finish in time, and the harvest window is the part that proves the plan works. Many gardeners look only at the sowing date and forget the harvest window. A crop that needs a long warm season must be sown early enough to ripen, and a crop that hates heat must finish before summer peaks. Reading the full calendar, not just the first date, is what turns a sowing date into a harvest you can actually eat.
For broccoli, start broccoli indoors or sow directly, then transplant seedlings about 45 cm apart in rich soil, and water steadily, because dry spells make heads small and bitter. This is practical knowledge, not theory. Soil warmth matters as much as air frost, so cold soil can delay germination even after the last frost date. Good drainage, sun, and steady watering matter too, especially in the first weeks after sowing. A calendar gives you the dates, and your soil and weather decide the exact day, so check the soil with your hand before you sow.
Mark the sowing window on your calendar and sow at the start of the window if your soil is warm, or at the end if it is still cold. This is a practical habit, not a theory. Sow a small batch first, then sow again a week or two later if the calendar suggests succession sowing. Compare how the two batches grow and keep notes on which dates worked in your garden. The best dates for your soil are often a week or two different from the average dates, and your own notes are the fastest way to learn them.
There are limits to what a simple calendar can do. it uses average frost dates, so a cold year or a warm year can shift every date by a week or more. It cannot predict this year weather, a late cold snap, a heatwave, or pests in your garden. Those questions need a local forecast, frost cloth, and regular checks of your plants. What the tool can do is make sure the dates behind your plan are sound, so that if the weather cooperates, the crop also has time to grow. Sound dates are the foundation, and daily care builds on top of them.
El Calendario de Siembra de Brocoli