Using Egg Cartons to Start Seeds Indoors – Seed Starting Fun

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Starting seeds indoors in egg cartons is one of our family’s annual gardening traditions! We look forward to it every winter. Using egg cartons to start seeds is just about as easy as it gets.

(Well, besides my other favorite seed starting method – germinating seeds in plastic bags with wet paper towels!)

I highly recommend this seed starting method for gardeners of all ages, especially kids. Last year I gave each of my daughters their own egg carton to plant whatever seeds they wanted! It was great fun to see what they each chose, and my youngest loved it so much that she wanted to start a second tray!

Using Egg Cartons to Start Seeds Indoors - Zinnia Seedlings Growing in Turquoise egg tray
Using Egg Cartons to Start Seeds Indoors is so much fun! Here are some Zinnia Seedlings Growing in our turquoise egg tray.

Benefits of Using Egg Cartons to Start Seeds

You may find quite a few benefits when planting seeds in egg cartons. Here are my favorite reasons why you should start seeds in egg trays.

  • Individual cells are perfect for tiny seedlings. Egg trays with 12 or 18 cells offer much opportunity for variety of what you plant.

  • Reduce, Reuse, Recycle! Reusing egg cartons for seed starting gives these trays a new lease on life. Styrofoam egg cartons usually end up in the trash anyway, so this is a much better alternative.

  • Enjoy easy configurations for mass seed starting. If you plan to start quite a large number of seeds, you can save up several egg cartons to achieve your goals. In most cases, the egg cartons fit nicely side to side or front to back under your grow lights.

  • Removal of seedlings for transplant is effortless. Simply pinch the Styrofoam pocket with the seedlings you wish to transfer and gently coax the entire root ball, soil and all, out of the egg tray.

How to Plant Seeds in Egg Cartons

Germinating seeds in egg cartons is easy and so much fun!

First, let’s gather a few materials to get started.

I promise the waiting is the hardest part!


Gather these materials before you start using egg cartons to start seeds.

  • Seeds
  • Potting Soil
  • Spray Bottle
  • Empty Egg Cartons
  • Knife or Sharp Tool
  • LED Grow Lights
Planting Seeds in Egg Cartons - Here's Apricot Lemonade Cosmo in the front with Money Plant in the next cell back.
Planting Seeds in Egg Cartons – Here’s Apricot Lemonade Cosmo in the front with Money Plant in the next cell back.

Starting Seeds in Egg Cartons: Instructions

Begin with a Styrofoam egg carton seed starter tray and follow these steps to get started.

  1. Create drainage holes. Take your Styrofoam egg carton and use a knife or other sharp implement to poke holes in the bottom of each cell.
  2. Fill with potting soil. Lightly fill each egg tray cell with potting soil.
  3. Read the instructions for each kind of seed you plan to grow. Figure out how deep to plant seeds in egg cartons. Also, some seeds may do best if you surface sow. You may not need to bury them at all!
  4. Make an indentation in the center for seeds being covered. Poke a small hole in the center of the soil in the seed cell for large seeds. For smaller seeds, poke a few smaller holes spaced out across the soil. (As a general rule of thumb, I usually plant a minimum of two seeds in case one is a dud.)
  5. Drop seeds into the holes in the soil. Aim to plant one seed per hole.
  6. Lightly replace the soil to cover the seeds. Gently cover the seeds with soil.
  7. Immediately label the type of seeds. I usually write the name of each seed variety directly on the egg carton.
  8. Water the soil adequately. Use an indoor plant spray bottle to dampen the soil for each seed you’ve planted.
  9. Set the seeds in egg cartons under grow lights. For best results, I grow my seedlings under LED grow lights with excellent quality ratings.

Growing seeds indoors in egg cartons is so easy and so much fun! You and your family will be sure to create such wonderful memories starting seeds together.

Let’s Get Started!

Tips on Using Egg Cartons to Start Seeds

Once you’ve planted seeds in the egg trays, you can focus on maintaining moisture levels and ensuring enough lighting.

Here are some tips to help you ensure the best chances of success when starting seeds in egg cartons.

  • Check seed trays daily to ensure proper moisture for the soil. Spray with the spray bottle to dampen soil as needed. Avoid leaving standing water.
  • Harden off seedlings before transplanting outside. Make sure you help the seeds acclimate to the harsh natural sunlight and outdoor climate by hardening off over the course of a week or two.
  • Transplant tall seedlings to bigger pots. A pack of 3” or 4” nursery pots can go a long way when using egg cartons to start seeds. Some seedlings like sunflowers and cucurbits, like pumpkins and cucumbers, may swiftly outgrow the egg cartons.
Dog napping near seedlings growing in egg cartons on wooden deck
Here’s our beloved pup napping near our 2021 seedlings growing in egg cartons on the deck.

By the way, you might also enjoy our Google Web Story on 3 Simple Ways to Start Seeds. Do you have any questions about using egg cartons for starting seeds? Feel free to leave us a comment and we’ll get right back to you!

Also, if you have any tips or favorite stories, be sure to share those, too! We love hearing from you!

Happy Seed Starting!

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03.15.23 – Updated to add link to gws and improve spacing.

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  1. I planted a 3-5 tomato and pepper seeds in each egg pod expecting half to not germinate. Most did sprout and now there sometimes 4 in each pod and they have outgrown the pods. What would be the best way to re-pot them without damaging them? Separate them or re-pot together?

    1. Hi Steve, thanks for your comment – congrats on excellent germination rates! That’s fantastic. What I do is try to gently separate them when they each have a set or two of true leaves. Sounds like yours already do with the 4″ height, so that’s great. I would prep 3″ – 4″ nursery pots if you have them. Depending on where the seedlings are in the pods, you can probably gently separate them one seedling at a time by pulling the soil chunk apart a bit to reveal each individual root system. Tomatoes will also root from their stems, so I think they will be fairly forgiving as you attempt this. Good luck and feel free to come back and let us know how it works out for you! Happy Gardening!

  2. I am starting sunflowers in the paper type egg cartons, but I see Styrofoam cartons used here. Does it matter? How tall should the sunflower plants be before transferring to the flower bed?

    1. Hi Steve! Great to hear from you – thanks for your excellent question. I should update the article to reflect this – I grow my seeds in whichever egg cartons I have available at the time. I start in both. 🙂 I think you can transplant the sunflower seedlings as soon as they’re 3 – 5 inches tall, depending on your preference, but beware if you have rabbits or groundhogs. If you do, I would put wire wastebaskets from Dollar Tree or other barriers over or around the sunflower seedlings. The bunnies and groundhog in our area have devastated my sunflower seedlings so I try to keep them covered as best I can until they really take off and grow taller.

      By the way – if you started the sunflower seeds indoors, be sure to harden them off before transplanting outside. They need to get used to the hot sun and warm temps so they don’t burn or go into shock. I have a post on this on the sidebar. 🙂 Best of luck to you! I bet your garden is going to be amazing.

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