These dates are very specific to Minneapolis, Minnesota which is in USDA hardiness zone 4b. If you are using this as a guide, adjust dates by a week for every 100 miles you live to the north or south of Minneapolis. Also, we are having a very early season — some things are more than a month early this year. Obviously, anything beyond today is just my best guess.
January
All month: read, plan.
February
19 New hoop house complete.
22 Seeds started indoors: leek, winter density lettuce, red russian kale, lacinato kale, st. johns wort, spinach, swiss chard, mesclun lettuce.
23 Scattered some lavender seeds outside in the warmest microclimate I can find in my yard. Covered with snow. Results pending. (RESULT: nada.)
March
11 Planted some peas outside in the garden (south side of house microclimate — frost is out early there)
15 Deadline for starting most seeds indoors (complete guide)
20 Harvest of chives, sorrel begins (two weeks earlier than usual)
22 Magnolia in full bloom
April
2 Sowed seeds in two smaller stock tank gardens: carrots, radishes, arugula, lavender, calendula, St. John’s Wort, nasturtiums. First harvest of asparagus.
11 First lettuce harvest of 2012! Love that hoop house!
12 Apple tree blossoms start opening
15 harvest of perennial herbs begins — thyme, oregano
May
7 planted much of garden. Seeds: parsnips, bush green beans, melons, cukes, fennel, more peas. Plants: bok choi, green onions, leeks, shallots. Some tiny apples can be seen so some blossoms must have survived the frost 3rd week of April.
9 Alpine and regular strawberry plants in full bloom. Also blooming: wild columbine, virginia bluebells. Tulips done after an unusually long bloom (most of April).
16 Official last frost date for Minneapolis, but my garden is fully planted and the beans and cukes are already sprouted. Tomatoes are actually growing a bit. Planted over a series of 3 days, May 10-12. Peas, chives and bearded irises are now blooming, and first harvest of oregano and thyme is drying. Rhubarb season wrapping up.
June
5-10 Alpine strawberry harvest begins
10-15 Harvest snap peas, lettuces, baby greens, regular strawberries
15-20 Garlic scape harvest begins. Add beneficial nematodes to garden.
20-25 Start watching for cabbage worms and adult squash vine borers
25 Deadline for hanging sticky traps in apple tree
July
1-5 First harvest of cabbage (if planted as tranplant in May), bush green beans
5-10 Raspberry season begins. Also: some baby tomatoes, greens, small turnips and beets
10-15 Harvest garlic bulbs
26 Sow carrot, spinach, lettuce, swiss chard seeds outside in hoop house/cold frame for fall/winter harvest (also kohlrabi, radicchio, scallion)
25-30 Start looking for squash vine borer larvae
August
1-5 Sow more seeds outside in hoop house/cold frame for fall/winter harvest (more spinach, radish, beet)
1-5 Harvest season for peppers, cucumbers, and tomatoes begins
September
15 Final sowing of seeds outside in hoop houses for later winter harvest (spinach)
15 Official “first frost” date in Minneapolis.
October
20 Deadline for adding any transplants to hoop houses (greens)
November
December
Yes, planning and recording is key to good consistent results. Can’t speak to your dates since I’m in Seattle, but planning is on everyone’s minds I think: my post today is the launch of my garden journal. You can see my (not completely ever done) planting guide (excel spreadsheet) under the downloads section, too, if you want to check it out. http://www.nwedible.com/downloadables