The Ultimate Free Seed Starting Calculator & Planting Schedule

Welcome to Simple Seed Guide, your free custom planting dashboard. Figuring out exactly when to start seeds indoors can be one of the most confusing parts of gardening. If you plant too early, your seedlings get weak and leggy. If you plant too late, you might miss your harvest window before the fall freeze. Our seed starting calculator takes the guesswork out of your spring garden planning.

How to Find Your Last Frost Date

Your local "Last Frost Date" is the most important metric in gardening. It is the historical average date of the final freezing temperature in your zip code. Everything you plant revolves around this date. Simply use our Auto-Detect button above, or select your USDA Hardiness Zone, and our tool will automatically calculate your indoor seed starting schedule and direct sowing dates.

Indoor Seed Starting vs. Direct Sowing

Not all seeds like to be treated the same way. Some plants, like tomatoes, peppers, and eggplants, require a long, warm growing season. These need to be started indoors under grow lights weeks before your last frost. Other plants, like carrots, radishes, and beans, have fragile taproots and hate being transplanted. These should be direct sown (planted directly into the garden soil) once the weather is right. Use our method filters to sort your list and plan your garden beds perfectly.