Field Guide · Propagation · 7 min read

How to Stratify Pawpaw Seeds

Pawpaw seeds need 90 to 120 days of cold to sprout, and they die if they dry out. Get those two things right and the rest is easy.

Written on the farm by Nathan Story · Story Thyme Farms, Missouri · Updated

Story Thyme Farms · Bench cardFall through winter

How to stratify pawpaw seeds

Asimina triloba. Cold moist stratification

DifficultyEasy but slow
Cold needed90–120 days, 32–40°F
Never let themDry out or freeze
Sprout at75–85°F, deep pots
1Cleaning the seedsEat the fruit and keep the seeds wet
2Bagging themPack them in damp moss in a zip bag
3The cold period90 to 120 days in the refrigerator
4Sowing themDeep pots, warm soil, and patience
5The first two yearsKeep seedlings shaded for two summers
Materials needed · Long-fiber sphagnum · Zip-seal bags · Tall tree pots · Shade cloth · Heat mat
Written on the farm · Missouristorythymefarms.com/guides/how-to-stratify-pawpaw-seeds

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How to tell when a pawpaw is ripe How to harvest pawpaws →

The long version

Watercolor plate of pawpaw seeds in damp moss, one with a taproot emerging
Asimina triloba · field plate

Any pawpaw seed you spit onto a plate in September can become a tree, but only if it never dries out and gets a proper cold period first. Two mistakes account for most failures: a seed left dry for even a few days is usually dead, and a frozen one is too. A refrigerator handles the rest.

  1. Step 1 · Cleaning the seeds

    Eat the fruit and keep the seeds wet

    Watercolour plate of large flat brown pawpaw seeds being rubbed clean of orange pulp in a bowl of water, a halved pawpaw fruit beside showing custard flesh

    Work the large brown seeds free of the pulp in a bowl of water and rub them clean. From this point on they must never dry out. Even three days on a dry counter can drop germination from around ninety percent to under twenty.

  2. Step 2 · Bagging them

    Pack them in damp moss in a zip bag

    Watercolour plate of brown pawpaw seeds nested in damp green sphagnum moss inside a clear zip bag with a handwritten date label

    Mix the seeds into a handful of moist sphagnum moss or barely damp peat that you have wrung out, seal them in a bag with a little air in it, and write the date on it. The moss keeps the moisture even and helps hold down mold. Check the bag once a month, and if you see fuzz, rinse the seeds and replace the moss.

  3. Step 3 · The cold period

    90 to 120 days in the refrigerator

    Watercolour plate of a labelled bag of pawpaw seeds in damp moss sitting on a refrigerator crisper shelf, cool blue-white light

    Put the bag in the refrigerator at 32 to 40 °F, where the crisper drawer works well, for at least 90 days. We give ours the full 120. Do not use the freezer, which kills them. Mark the finish date on a calendar so spring does not catch you off guard.

  4. Step 4 · Sowing them

    Deep pots, warm soil, and patience

    Watercolour plate of a tall narrow tree pot cut away to show a pawpaw seed sown an inch deep with a long white taproot diving to the bottom before any shoot appears

    Sow the seeds an inch deep in tall tree pots, because the taproot grows down many inches before any shoot appears. At 75 to 85 °F the root emerges in two to four weeks, and the shoot can take up to two months more. A pot that looks empty usually is not, so do not dump it out.

  5. Step 5 · The first two years

    Keep seedlings shaded for two summers

    Watercolour plate of a young pawpaw seedling with two broad green leaves growing under dappled shade cloth, forest-floor light

    Wild pawpaws sprout on the forest floor, and seedlings sunburn in full light. Grow them under 50 percent shade cloth, or on a bright porch out of direct afternoon sun, for their first two years, then plant them out. Seedlings fruit in five to eight years, and you need two trees for pollination.

Materials needed
Long-fiber sphagnumZip-seal bagsTall tree potsShade clothHeat mat

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Questions we actually get

Can I just plant pawpaw seeds outside in fall?
Yes, and it is the lazy method that works: sow fresh seeds two inches deep where you want trees, mulch, and let the real winter stratify them. Protect the spot from squirrels, they find pawpaw seeds delicious.
Will seedlings match the parent fruit?
Close but not identical. Seedlings from good fruit usually make good fruit, but named varieties only come true through grafting. For a wild patch or rootstock, seeds are perfect.
Why is my pawpaw seedling's taproot poking out the pot bottom already?
That is the species. The taproot can hit ten inches the first season, which is why shallow trays fail. Use the tallest pots you can find and transplant whole, without teasing the root ball apart.
From the plant library

Pawpaw — the full profile

Zones, cold-hardy cultivars, spacing, feeding, and where to buy one already rooted.

Open the pawpaw guide →