Eggshell Pots for Starting Seeds
If you frequently start plants from seeds indoors, you probably already appreciate the advantages of seed starting in biodegradable pots like peat pots and pots made from old newspaper.
Lately, I've fallen in love with using eggshells as seed-starting pots.
They cause less mess than other biodegradable pots, they're a cool way to re-purpose old eggshells and I love the way they look. In fact, they're so cute, I sometimes give them as gifts!
And pots like eggshells that rot make the transplanting process easy: simply plant the seedlings, pots and all, in the ground when they're ready.
I first saw pictures of eggshells used as seed pots on Pinterest. Although I liked the way they looked, as a gardener I wasn't all that impressed.
The shells were so shallow—less than an inch deep! That's not enough room for seedlings to establish a good root system. Although they looked clever and cool in the pictures, I had a feeling that those seedlings would soon expire once they were transplanted outdoors.
Then one morning when I "mis-cracked" a large egg, sheering off only the very top of it, I thought: "I could start a seed in that." The shell was over two inches deep, enough room for a seedling to set down a good mass of roots.
Select a large egg & break off just the very top.
If you have an old egg carton, use it to hold your eggshell seed-starting pots. Egg cartons are narrow enough to fit neatly on most windowsills, and if you use a carton made from cardboard, it will absorb any water you spill.
I usually wait until I've collected an entire egg carton of empty shells before I sow any seeds, but you could easily sow a seed or two at a time.
Clean out the eggshells.
After emptying an eggshell, rinse it thoroughly with water or water and vinegar, scraping away the membrane on the inside with your finger to make the shell more porous. Then throw the broken bits from the top into the shell into your egg pot. (Hey, they can't hurt!)
Sow your seeds according to package directions just as you would in any other seed-starting pot.
Fill the eggshells with moistened seed-starting mix.
You could use regular potting soil, but seed-starting mix (either store bought or your own mix) is light enough and airy enough that water can drain easily and new roots can easily spread.
During germination, it's important to keep the soil warm (not hot) and moist (not wet).
Plant at depth recommended on the seed package.
If you're sowing seed that you've saved yourself, you're probably familiar enough with the plant that you know the preferred planting depth of its seed. If not, the general rule is to sow seeds at a depth equivalent to their width.
If you're starting packaged seed, follow the directions on the label for planting directions.
Sow two to three seeds per pot. (If you tend to spill, no worries. You can always clip off extraneous seedlings later.)
The photo above is of cilantro seed, which only needs a light covering of soil, about a ¼ inch.
Place the eggshell pots in a sunny windowsill & keep moist.
Place your carton of eggshell pots in a sunny windowsill and keep the soil moist. When the seed sprouts, you'll probably have to water more than once per day.
As you can see in the picture above, I'll soon have to thin a few of these eggshell pots of cilantro, as I spilled too many seeds into some of the shells. So as not to disturb the roots, I'll clip off the extra seedlings at the soil line with a pair of nail clippers.
Harden off & transplant new plants in their shells.
What do you routinely start from seed?
Because they're in their own handy carrying case, hardening off seedlings in eggshell pots is easy: simply place the egg carton of seedlings in a shady spot a few hours per day for a week or two until they become acclimated and strong enough to survive outside.
Planting the seedlings is a snap, too. Just crack the bottom of the shell against something hard, like a rock, the sidewalk or the beams around your raised bed garden, and plant it, eggshell pot and all.
A study conducted by agronomist and soil specialist Charles C. Mitchell through Auburn University shows that hand-crushed eggshells (as opposed to finely ground shells) leach little calcium into the soil and have almost no impact on soil pH.
But even if eggshell pots don't provide much plant nutrition, in my personal experience, they do improve soil texture—and if your soil is part clay like ours is, that's a good benefit.
Basic Tips for Improving Germination
As you can tell from the photos, I'm currently growing cilantro from seed to overwinter outdoors. In our Zone 7 garden, cilantro is one of those culinary herbs, like parsley, that can be sown in summer and either harvested in the fall or late winter.
Because it's still hot here, I opted to start our cilantro indoors. (Sometimes seeds won't germinate when direct sown in hot weather.)
Once the seedlings are more mature, I'll plant them in our raised beds and, when temperatures drop, cover them with row covers.
About the Author
The Dirt Farmer has been an active gardener for over 30 years.
She first began gardening as a child alongside her grandfather on her parents' farm.
Today, The Dirt Farmer gardens at home, volunteers at community gardens and continues to learn about gardening through the MD Master Gardener program.
© 2013 Jill Spencer