Online Tools & Calculators

Planning Tools & Calculators

Use Johnny's interactive planning tools and calculators to help with planning and scheduling your growing season. From calculating how much seed you'll need and when to plant, replant, and harvest, to the resources you'll require to build your new high tunnel, our calculators can help you streamline your operation to become more productive, profitable, and enjoyable.



  • Seed-Starting Date Calculator for Seedlings
    This tool figures the dates for starting seedlings indoors and for safely planting particular early crops outside, based on the frost-free date that you specify.

  • Succession-Planting Calculator Workbook (XLSX)
    This spreadsheet calculator allows you to input the date of your first planting of each crop, then it calculates the dates for later plantings. It also allows you to input your first fall frost date, counting back the appropriate number of days to determine the last date to plant and still get a crop before frost.
  • Target Harvest Date Calculator Workbook (XLSX)
    Use this tool to coordinate production of one of more crops for harvesting by a particular user-defined target date or otherwise important event. Determine seeding date relative to a specific harvest date.
  • Fall-Harvest Planting Calculator Workbook (XLSX)
    This spreadsheet calculator works backward from your first fall frost date, to determine the best date on which to start seeds for crops that will mature successfully as summer warmth and light wane into the fall.
  • Overwinter Flower Trials • Seeding Date Calculator Workbook (XLSX)
    On entering your last 10-hour day of the year, this calculator displays a range for your earliest and latest seeding dates as well as the seedling transplant date, for each of 25 flower crops suitable for overwintering. Based on the results of Johnny's Multiyear Overwinter Flower Trials.


  • Grower's Library
    Explore our extensive collection of information on growing, including manuals, charts, planting and growing guides, technical articles, instructional videos, and more. Browse information specific to each of our seed and plant product lines: vegetables, flowers, herbs, and farm seed, as well as tools, supplies, methods, organic certifications, labels, and material safety data sheets.
  • Flower Culture Comparison Chart PDF
    This chart can help you select the best flowers for your situation. Information includes application, germination time, transplant information, days to harvest, and growing tips.
  • Herb Culture Comparison Chart PDF
    This chart will help you plan your herb growing strategy. Information includes germination time, transplant recommendations, and days to harvest.
  • Vegetable & Sunflower Planting Programs
    A series of Planting/Harvesting Programs indicating which varieties of particular crops are best adapted for planting and harvesting across the different seasonal slots, pretrialed and selected for you by Johnny's Research Team.