A well-planned planting calendar is your roadmap to a continuous, productive garden. Knowing the optimal sowing times for vegetables, herbs, flowers, and ornamentals ensures strong germination, healthy growth, and peak yields. Whether you have an indoor seed-starting setup or an outdoor plot, this guide helps you map out monthly tasks—from seed sowing to transplanting—so you can harvest delight all year long.
Why Follow a Planting Calendar?
- Synchronize Growth Cycles: Align seed-starting with frost dates and seasonal light/intensity changes.
- Avoid Waste: Sowing too early or too late leads to poor germination and stunted plants.
- Maximize Harvest Window: Stagger plantings for a continuous supply, rather than one-time abundance.
- Plan Crop Rotations: Prevent soil-borne diseases and nutrient depletion by rotating families.
Key Dates to Identify
- Last Spring Frost Date: When danger of frost ends—time to start warm-season crops outdoors.
- First Fall Frost Date: When temperatures dip—move tender plants inside or finish cool-season harvests.
- Indoor Start Dates: Weeks before outdoor transplanting based on species.
Note: Check your local frost dates online or consult gardening apps for precise regional data.
Monthly Breakdown of Sowing Tasks
| Month | Indoors (Seed Starting) | Outdoors (Direct Sowing/Transplant) |
|---|---|---|
| January | Herbs (basil, parsley) | Peas, spinach, onions (sets) |
| February | Tomatoes, peppers, eggplants | Radishes, lettuce, kale |
| March | Broccoli, cabbage, cauliflower | Carrots, beets, potatoes |
| April | Cucumbers (for transplant), squash | Beans, corn, melons |
| May | Pumpkins, melons (transplant) | Tomatoes, peppers, eggplants (transplant) |
| June | – | Herbs (basil, cilantro), beans |
| July | Fall brassicas (broccoli, cabbage) for fall | Carrots, radishes, spinach |
| August | Kale, collards for fall | Lettuce, arugula, mustard greens |
| September | Garlic (cloves) for spring harvest | Spinach, peas (overwintering) |
| October | Indoor annual flowers (pansies) | Garlic (cloves), spring bulbs |
| November | Orchid or houseplant seeds | Cover crops (clover, vetch) |
| December | Planning, ordering seeds; lenten rose (helleborus) | Winter sowing of hardy greens under protection |
How to Use This Table
- Adjust to Your Zone: Move dates 2–4 weeks earlier for warmer zones, later for colder.
- Sequential Sowing: For crops like lettuce, sow small batches every 2–3 weeks to extend the harvest.
- Succession Planting: Combine fast-maturing (radishes) with slower crops (beans) in the same bed.
Indoor Seed-Starting Tips
- Timing: Start seeds 6–8 weeks before the last frost for tomatoes and peppers; 4–6 weeks for brassicas.
- Lighting: Use LED grow lights for 12–16 hours daily at 20–30 cm above trays.
- Heat: Provide bottom heat (seedling mats) at 24–26 °C for warm-season seeds.
- Labeling: Mark each tray with seed variety and sowing date to avoid confusion.
Transplanting Guidelines
- Harden Off Seedlings: Expose trays to outdoor conditions for 1–2 weeks, gradually increasing time and sun exposure.
- Soil Prep: Amend beds with compost and fertilizer 1 week before transplanting.
- Spacing & Depth: Follow seed packet recommendations; bury seedlings to their first true leaves for sturdy stems.
- Aftercare: Water deeply at transplant; mulch to conserve moisture and suppress weeds.
Direct Sowing Best Practices
- Soil Temperature: Ensure soil is above 10 °C (50 °F) for cool-season crops and 15 °C (60 °F) for warm-season.
- Depth & Thinning: Sow seeds at proper depth (usually 2–3 times seed diameter). Thin seedlings to avoid overcrowding.
- Watering: Keep soil consistently moist until germination—use a fine mist to avoid displacing seeds.
Extending Your Season
- Cold Frames & Cloches: Use simple covers to start earlier in spring and extend into fall.
- Row Covers: Lightweight fabric protects against frost and pests without overheating.
- Unheated Greenhouses: Offer year-round seed-starting—sow winter greens in December under cover.
Tracking and Adjusting
- Garden Journal: Record sowing dates, germination rates, transplant success, and harvest yields.
- Review & Refine: Analyze what worked and adjust next year’s calendar for earlier or later sowing.
- Weather Monitoring: Keep an eye on unexpected cold snaps or heat waves and be ready to protect or shade plants.
Sample 4-Week Sowing Schedule
| Week | Task |
|---|---|
| Week 1 | Start tomatoes, peppers indoors |
| Week 2 | Sow lettuces and spinach outdoors |
| Week 3 | Transplant brassicas into garden beds |
| Week 4 | Direct sow beans and carrots |
By following a structured planting calendar, you’ll harness seasonal rhythms, maximize productivity, and minimize setbacks. With thoughtful planning and careful execution, every sowing date becomes a step toward a vibrant, fruitful garden—regardless of space or climate.