In this season when so many gardeners are starting their flowers and vegetables indoors, here are some thoughts about peat pots commonly used as containers for seedlings.
Some seedlings (zinnias, melons, castor beans, etc.) have fragile roots and can suffer during transplanting if you sow them in plastic pots or cell packs, as this exposes their root ball to damage when you try to transplant them. This is where peat pots come in.
These round or rectangular pots are made of compressed peat with some wood fiber. They are sturdy enough to be used as planting pots, but unlike plastic pots, they are porous, allowing air and water to circulate…. And also allow the roots of your seedlings to grow through them. You’ll actually see the roots penetrate the wall of the pot as they grow.
To use peat pots, simply fill them with your favorite seeding mix and moisten them well before sowing. Then sow the seeds, water and care for the seedlings until planting time. When the time comes, all you have to do is put the pot in a planting hole without removing the pot and cover it with soil. Water well… and your seedlings will continue to grow without slowing down since they have never been subjected to transplant shock. Not only will the roots grow right through the walls and establish themselves in the surrounding soil, but the pot itself will decompose over time, leaving no trace in the soil.
This is so simple that you may wonder why I even bothered to explain it. Well, it’s because there are always people who manage to do everything wrong and then proudly post their mistakes on the internet.
Here’s a silly piece of advice you’ll read on the internet, “You need to tear off the bottom of the peat pot before planting so the roots can grow into the soil.” Wait a minute! The roots are already growing through the bottom of the pot. If you remove it, you will damage them…. and didn’t we just say that peat pots are specifically designed for plants with delicate roots? Just plant the whole pot: there’s no reason to rip anything off!
Worse, some people suggest peeling off the whole peat pot. More mischief! If you plan to remove the pot at planting time, why use peat pots at all? Plastic pots and cell packs are easier to remove and can be reused year after year, so they are cheaper. Use these if you want to remove the pot at some point.
However, there is something you may want to take away from a peat pot. When transplanting seedlings into peat pots, be sure to bury the entire pot. If the top rim is sticking out of the ground, it will act like a wick and dry out the root ball. So if part of the pot is sticking out, yes, you can tear that part off.
Use only for fragile seedlings
Let me reiterate something before I close: peat pots are an added cost when growing plants from seed, and one of the main reasons gardeners sow seeds is to save money. Peat pots offer no advantages over plastic pots or cell packs for most seedlings. It is simply a waste to sow tomatoes, petunias, marigolds and most other garden plants in peat pots. Reuse and recycle other containers for their care. Keep peat pots for seeds whose fragile roots would otherwise make transplanting difficult.
Seeds that need peat pots
The following plants all have roots that are either very fragile and therefore must be sown in peat pots, or so fragile that they will be set back considerably if the root ball is mishandled during transplanting.
- Amaranth or sweet lily flower (Amarantbus spp.).
- Amsonia or blue starflower (Amsonia spp.)
- Anise (Pimpinella anisum)
- Annual phlox (Phlox drummondii)
- Bachelor’s button (Centaurea cyanus)
- Baptisia or false indigo (Baptisia spp.)
- Bean, hyacinth (Lablab purpureus, syn. Dolichos lablab)
- Bedding lobelia (Lobelia erinus)
- Turnip or beet (Beta vulgaris Condivita group)
- Bells of Ireland (Moluccella laevis)
- Black-eyed Susan vine (Thunbergia alata)
- Blue laceflower (Trachymene coerulea, syn. Didiscus coerulea)
- Burning bush (Bassia scoparia, syn. Kochia scoparia)
- Cabbage (Brassica oleracea)
- California poppy (Eschscholzia californica)
- Clovewort, annual (Iberis amara)
- Carrot (Daucus carota)
- Castor oil plant (Ricinus communis)
- Celosia or cockscomb (Celosia spp.)
- Chervil (Anthriscus cerefolium)
- China aster (Callistephus chinensis)
- Clarkia (Clarkia unguiculata, syn. C. elegans)
- Climbing snapdragon (Asarina, Lophospermum and Maurandya)
- Cucumber (Cucumis sativus)
- Cup and saucer vine (Cobaea scandens)
- Cypress vine (Ipomoeaquamoclit and others)
- Dill (Anethum graveolens)
- Dwarf morning glory (Convolvulus tricolor)
- Eggplant or eggfruit (Solanum melongena)
- Periwinkle (Xerochrysum bracteatum, syn. Helichrysum bracteatum)
- Fennel (Foeniculum vulgare)
- Flax (Linum spp.)
- Four O’Clock (Mirabilis jalapa)
- Gerbera (Gerbera spp.)
- Globeflower (Gomphrena globosa)
- Heuchera (Heuchera spp.)
- Hollyhock (Alcea spp.)
- Job’s tears (Coix lacryma-jobi)
- Kniphofia, torch lily or tritome (Kniphofia spp.)
- Delphinium (Consolida spp.)
- Lavatera or tree mallow (Lavatera spp.)
- Lisianthus (Eustoma grandiflora)
- Lovage (Levisticum officinale)
- Mist flower (Nigella damascena)
- Lupine (Lupinus spp.)
- Malope or mallow root (Malope trifida)
- Melon (Cucumis spp.)
- Mexican poppy (Argemone spp.)
- Mignonette (Reseda odorata)
- Milkweed (Asclepias spp.)
- Moonflower (Ipomoea alba)
- Morning glory (Ipomoea spp.)
- Nasturtium (Tropaeolum spp.)
- Nemophila or blue-eyed pea (Nemophila spp.)
- Nolana (Nolana paradoxa and N. humifusa)
- Painted tongue (Salpiglossis sinuata)
- Peanut (Arachis hypogaea)
- Sweet bell pepper (Capsicum annuum)
- Perennial pea (Lathyrus latifolius)
- Perilla (Perillafrutescens)
- Persil (Petroselinum crispum)
- Poppy, annual species (Papaver spp.)
- Purslane or moss rose (Portulaca spp.)
- Pumpkin (Cucurbita pepo)
- Quaking grass (Briza maxima)
- Rodgersia (Rodgersia spp.)
- Pumpkin (Cucurbita spp.)
- Chickweed (Limonium sinuatum)
- Summer savory (Satureja hortensis)
- Sunflower (Helianthus annuus)
- Chickweed (Lathyrus odoratus)
- Toad lily (Tricyrtis spp.)
- Tulip poppy (Hunnemannia fumariifolia)
- Watermelon (Citrullus lanatus)
- Zinnia (Zinnia spp.)
- Zucchini or zucchini (Cucurbita pepo)