What does this tool do?
This tool compares today's date against the planting windows for every crop in the planning library. A planting window is a span of weeks before or after a freeze date, which is how extension planting schedules are usually written. If today falls inside the window, the crop appears in your list with the action it needs: start indoors, direct sow, transplant, or fall sow.
It also looks ahead. Crops whose windows open within the next three weeks are listed under "opening soon" with the date the window starts, so you can buy seed, start trays, or clear a bed before the window arrives.
What each action means
Start indoors
The crop needs weeks of growth under lights or on a bright windowsill before it goes outside. Tomatoes, peppers, and eggplant are the usual indoor starters because they need a long season and cannot go out until frost risk is low. Missing this window means buying transplants later or waiting for next season.
Direct sow
The crop goes straight into the garden soil. Peas, carrots, radishes, beans, and spinach prefer this because their roots dislike disturbance. A direct-sow window opening means the soil should be workable, not just the air warm.
Transplant
Seedlings started indoors move into the garden during this window. Transplant timing for tender crops falls after the last freeze, while hardy crops like broccoli and cabbage can move out several weeks before it.
Fall sow
Cool-season crops get a second season when they are sown in late summer so they mature as weather cools. These windows count backward from the median first fall freeze.
How the windows are calculated
Each crop carries week offsets from extension planting guidance. Lettuce, for example, can be direct sown six to three weeks before the median last spring freeze, and again ten to six weeks before the median first fall freeze. Your ZIP code supplies the freeze dates from the nearest NOAA station, and the tool checks whether today sits inside each window.
Because the windows anchor to median freeze dates, they describe the typical year, not this specific one. A cold, wet March can push real sowing later than the window suggests, and a warm one can pull it earlier. Soil temperature matters more than the calendar for germination.
How to use the list
Work through the list in order of urgency. The days-remaining number shows how much of the window is left, so anything with a short window goes first. Indoor starts are the easiest to miss because they happen months before outdoor planting feels urgent.
If nothing is in a window this week, check the "opening soon" list. Late winter and midsummer can both look quiet while still being exactly the right time to prepare seed trays or plan a fall bed.
Common mistakes
Treating the window as a deadline
A window ending means the last comfortable sowing date, not that sowing the next day is pointless. Shorter season varieties can still succeed slightly past a window; the harvest just gets riskier or smaller.
Ignoring soil temperature
Seed packets and windows both assume the soil is ready. Cold, soggy soil rots bean and corn seed even inside a correct window. A cheap soil thermometer settles the question faster than the calendar.
Sowing everything in one week
An open window is a starting gun, not a requirement to sow the whole packet. Splitting a sowing across the window spreads the harvest and hedges against a freak freeze or heat wave.
When this tool may not be the right choice
The windows cover common garden crops with clear freeze-date relationships. Perennial plantings like asparagus crowns or fruit trees follow different timing, and warm-season lawn or cover crops use soil temperature instead of freeze anchors. For those, check the plant's own page or your state extension planting guide.
Gardeners in nearly frost-free climates will see windows anchored to freeze dates that barely constrain their season. The tool still lists openings, but year-round growers can sow most cool-season crops far outside these windows.
Where our data comes from
Freeze dates come from the NOAA 1991 to 2020 climate normals at the station nearest your ZIP code. Crop windows come from university extension planting guidance and are expressed as week offsets from the median freeze date. Both are planning estimates: cultivar maturity, microclimate, and this year's weather can move the useful date by a week or more in either direction.
Frequently asked questions
Why does one crop appear under more than one action? Each crop carries separate windows for indoor starting, direct sowing, and transplanting, and an opening window can sit beside a different action closing soon. Check the action label, not just the crop name.
A window just closed. Am I too late? Windows are probabilities built on median freeze dates. In a mild year a late sowing still works, especially for quick crops, but expect a smaller or later harvest. The fall planting calculator shows which sowings remain.
Why is my list empty or very short? You are between windows or outside the season. In deep winter and late fall nothing is inside a sowing window, and the "opens soon" list is the planning view for those weeks.
