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Temperate Seed Starting & Planting Calculator

A few years ago I wrote a guide on how to figure out when to start your seed and made a free seed starting online calculator. It needed an update… Badly… I am pleased to introduce the new (also free) Temperate Seed Starting & Planting calculator. Simply put in your first and last frost dates for your region and over 40+ of the most popular vegetables, herbs, and flowers will automatically calculate when you should plant your seeds.

New In This Seed Starting & Planting Calculator

There are a lot of little things but the major updates:

  • Succession Planting Calculation
  • Fall Planting Calculation
  • More Vegetables
  • Additional Planting Information
Seed starting calculator with fall planting, succession planting, indoor & outdoor dates

But Wait There’s More!

I love sounding like an infomercial! No truly there is more. With only two dates, you can now calculate when to start seed indoors, when to plant seedlings or seed outdoors, when to plant seeds for a fall yield, and dates for succession planting. All in one sheet! I also added a second sheet with planting details such as seed depth, seed spacing, ranges for harvest, and sun needs. I find it useful to have all those details handy when I get seed from seed swaps or order from companies (ahem… Baker Creek) that assume I just know when to plant this and that. I have a good memory… But not that good!

Additional information to help you plant seeds such as planting depth, harvest times, spacing, and succession dates for flowers, vegetables, and herbs.

Are You an Old School Seed Starter?

Lots of people still like paper and pencil and that’s okay. In my previous guide to calculating seed start dates I outline exactly how to calculate all the seed starting dates by hand. (Linked for you convenience) You can still use this free seed starting calculator to see the number of days before frost, days to harvest, and days for succession planning to use in your calculations.

So How Do I Get/Use this Seed Starting & Planting Calculator?

  1. Click on this link to the Seed Starting & Planting Calculator to make a copy for your own.
  2. Research your average last and first frost date. I like to Google “Average Frost Dates (Insert your location)” and look at a few sources to get the latest weather patterns. However, if you live in the United States and do not want to research the Farmers Almanac website has a search page for that. (Again linked for you convenience; Cause I am awesome like that)
  3. Insert those dates into the appropriate boxes
  4. Follow the planting dates! They should work for most temperate climates. If you are approaching the arctic or tropical zones will need to use techniques to either extend your season or shield cold loving crops from the heat.

Yes, it is that easy but if you want a little more information about how it works behind the scenes and what you can play with here you go:

Dates for succession and fall planting are triggered by the X for (wait for it) in the Fall and Succession planting columns. They are calculated by the first frost date, days of harvest, and recommend succession planting dates. If you want longer times between successions you can change the time in the second Planting Tips sheet. I mention it, because succession planting dates are much more subjective depending on the actual days to harvest, and how much of a crop you want to get. I just can’t eat that many beets or lettuce and would never want to plant them at such small intervals, but technically you CAN!

I also think it is important to note that crops that don’t make good fall candidates are set to be harvested 45 days before first frost. Generally, those warm weather crops just seem to start lagging when the sun decreases and cooler temperatures appear, but you could technically push the growing season longer. I’m also very conservative and have cool weather crops harvesting 2 weeks prior to frost for fall and succession planting. Why? Because if you happen to have a cool autumn their growth will be stunted and you can run the risk of not getting a final fall crop. There many ways to extend that fall crop with row covers, tunnels, cold frames, etc. However, this sheet is meant to calculate growth in open ground or open raised beds.

Why a Free Seed Starting & Planting Calculator?

Honestly, I couldn’t find a calculator or excel sheet that did it all. A number of gardening websites offer utilities to calculate seed starting dates OR succession planting OR fall planting, but not all of those dates in one place. The seed starting utilities also tend to forget about first frost when figuring succession days. So yep, I thought I could make something better, and so I did.

All I ask in return is that if you find this free seed starting and planting calculator useful that you share this post with others on social media or comment below. Also if you want me to include additional vegetables, flowers, or herbs comment below! I’ll see what I can do!

FREE online Seed Starting Calculator.  Includes planting tips, succession planting, fall garden planting, indoor and outdoor planting dates for 40+ vegetables, herbs, and flowers.

23 thoughts on “Temperate Seed Starting & Planting Calculator

  1. […] Use our Seed Starting Calculator to ALSO plan out your Succession Planting  […]

  2. Thank you, thank you, THANK YOU!!! This is AMAZING and I can’t wait to share it. This year I’m aiming to start all my own seeds for the first time this year and I can’t tell you how helpful this is, thank you for your hard work, and for sharing it so freely!! Those kinds of IF statements would kill me — and yours is so elegant! I’m trying to understand a few things, sorry if this is annoying! I totally don’t expect an answer but figured it can’t hurt to ask!
    1. COL G, “Frost Plant Date – (negatives planted before frost)”: This is in weeks, right? Meaning that plant/seed is ready to be outside (either transplanted or set outside to harden off) that # of weeks before or after the last frost date, right?
    2. COL H, “Seed Starting Date,” is when is should be planted, either starting indoors our direct sow outside?
    3. COL I, “Outdoor Planting Date,” is when the seedling should be transplanted, correct?


  3. This is an incredible effort of love. I am somewhat familiar with Excel and its amazing powers so I appreciate the information and work put into this sheet.
    I have noted though that two very commonly grown items are not included. Peppers and rosemary are the two items that I beleive would be benificial for many to have included.

  4. Thank you very much. It is a great resource, I was really desperate on finding something to help me plan. I grow a few other crops not so common and I would like to add them in the list. I was wondering how you worked out the frost plant day negative value. What is the unit for the sowing distances? I hope you don’t mind sharing the link in a few facebook groups

    1. The unit is in inches and you feel free to share. Just link back to the page! Can you tell me more about what you mean about frost negative value? I think you might mean the negative periods? If so, that means you can plant them before the last frost. Finally, let me know what you want added. I can probably add some additional plants to the list!

  5. Thank you so much for sharing your knowledge! It is greatly appreciated. FYI the website is showing that it is Not Secure.

    1. Yep, I don’t have anyone logging into anything, so I don’t have any need to pay for a certificate at this time.

  6. I’ve been looking everywhere for a seed starting calculator that is easy for met to plan accordingly (and visualize succession dates).As I am unfamiliar with Sheets/Excel, does anyone know how I would be able to add and build on this for my flowers? I have a lot of flowers to plant-some direct some indoors, some winter sowing.I can’t keep track! haha I think I have a seed addiction. Anyhow, I tried to add some rows but it only let a few and then looked like it wasn’t the same. I wasn’t sure how I could maybe add successions as well (ie/ sunflowers, zinnias, other cut flowers). As someone with adhd, it’s been hard to organize gardening and starting dates but this is by far the best out there on the internet! I cannot tell you how much I appreciate that we can fill in our own dates too. I just needed an “approx” to visualize what my work flow will be for planting this year. Now on to other planning too. I think I should learn how to do these in Sheets whereit automatically calculates a date for you because that is amazing!!!

  7. Thank you so much for this helpful resource! I hope to be using it a lot!

    1. If you see any changes you need let me know.

  8. 2 more things:
    Just noticed the “planting tips” tab and my jaw dropped. I actually found this while looking for a seed to harvest days/dates chart. I was thankful for it even without that information. Now it is all I could ever want and more! Thanks so much!

    It’d be awesome if you could include Borage and Sunflowers in the flowers section in a future version.

    1. I will try to do some research get them added tonight. I actually grow both, but I haven’t planted borage in forever. It just kinda shows up in the garden at this point.

  9. Thanks so much for this!!! I absolutely love it! You are an absolutely amazing person for sharing this for free! I feel like the true heart of gardeners and farmers should be to put food on tables and by doing this for free and not profit you have demonstrated that you have that purpose and intent in your heart. I admire it very much. You have NO idea how much this will help my life!!!

    1. Glad you find it useful! We like to make useful things!

  10. This is GREAT! Thanks for sharing.
    It’s been awhile since I’ve used Excel, and I’ve never used it in GoogleDocs – but is there a way to sort it by seed starting date?

    1. Yes, if you go up to the data tab and select sort by range it will give you the option to use headers to sort much like excel.

  11. Fabulous! I can not thank you enough!

  12. Fabulous! I can not thank you enough!

    1. So glad you found our seed starting and planting calculator useful

  13. What a useful tool! It’s so easy for seed starting dates to sneak up on us. You have provided a great reminder and made it so easy to personalize. Much thanks.

    1. Glad you are finding it useful! I use the heck out of it for myself!

  14. Do you have a cape? because you’re a super hero! This calculator is incredible, and I can only imagine the amount of time, effort, and knowledge you put into it! From a relatively new gardener who is seeking knowledge, experience, advice and a straight forward (as much as it can be with all of the nuances of gardening) approach and guide, thank you so much for sharing this.

    1. Wow, this might be one of the nicest comments we have ever received! I put a lot of time into my garden and love helping people out. If you have any questions please reach out!

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