How do I build a planting calendar for my own climate?

Begin with frost information that applies to your location, then gather timing information for each crop and variety. Your calendar is a set of estimates based on those local and crop-specific inputs—not a universal list of dates.

The supplied Oregon State Extension material notes that Oregon has distinct growing regions with different season lengths and planting conditions. Its dates and examples are Oregon-specific, so use locally applicable frost information and crop requirements rather than copying them elsewhere. [S1]

Make an entry for each crop with its variety, your location or frost reference, growing method, crop-timing information, and the source of that information. For a fall crop, the key inputs include the applicable average first killing frost and the crop’s days to harvest. Include any indoor-growing period and allow extra time for slower growth in cool, short autumn days. Count backward from the frost date. [S1]

For an indoor start, use the frost-free date most applicable to your area, the crop-specific weeks until plants go outdoors, and the weeks needed to grow seedlings indoors. These inputs let you work out a planned set-out date and then count backward to a sowing date. The Central Oregon table illustrates this method; its example date is not a general date for other climates. [S2]

Here is a hypothetical arithmetic example, not a recommendation for any crop or location. Suppose your locally applicable average first killing frost is October 20, and your chosen crop information says 60 days to harvest. Counting backward 60 days gives August 21 as a starting estimate. If you also need 14 days of indoor growing and want to allow 7 additional days for slower cool-weather growth, count back 21 more days: the planned start would be July 31.

Those numbers are invented for the calculation example. Replace them with the frost information and crop- or variety-specific timing that apply to you. The fall-planning method—counting back from the average first killing frost and accounting for days to harvest, indoor growing time, and slower growth—is described in the Extension guide. [S1]

For indoor starts, write down the locally applicable frost-free date and the crop’s weeks to set-out and weeks to grow indoors. For example, if your own inputs give you a set-out date of May 15 and the crop needs 6 weeks indoors, count back 6 weeks to get an indoor sowing date of April 3. These dates are hypothetical arithmetic only; use your local date and crop timing instead. The Extension table demonstrates the calculation method, not dates for every region. [S2]

If a local frost reference or crop-timing figure is missing, mark it “unknown” rather than silently substituting a date from another region. Record where each input came from, and revisit the entry when you find information applicable to your location and growing method. The supplied sources describe scheduling methods but do not establish dates for every place, crop, or variety.