“I want to start and grow paw paw seeds. Can you give me your recommendation on a planting mix? I’m planting seeds in 4×14 containers. They’ll be in the containers for two years in the shade in hot Texas conditions before I plant them in the orchard. Pawpaws are considered tropical. The nursery that sells paw paw seed said I might want to add a 50/50 sand mix to potting mix to help pull the seed husk off the seedlings when they emerge. I’m afraid I’ll introduce a disease like damping off if I add sand to the mix. My orchard soil is all sand, so I have plenty. I’m not so sure adding my sand is a good idea. Thanks for your help!”
Question from James of Pilot Point, Texas
Answer: Thanks for your question about paw paw (Asimina triloba) seed germination. There are several things that you need to know before successfully growing paw paws from seed. First, they are temperate trees that survive in USDA Hardiness Zones 5-9, and the seeds need a moist chilling period (stratification) before germinating. Seeds need to be chilled for 100-120 days before they will sprout.
I recommend starting your seeds in smaller containers. You can either cover and chill them in a refrigerator or keep them outdoors uncovered during winter for natural chilling. Just never let the mix get dry. A super well-drained seed germination mix of 50% peat and 50% purchased sand is recommended to ward off fungal diseases, like those that cause damping-off (Pythium and Phytopthera). The better the drainage, the more difficult it is for these fungal diseases to thrive.
After the chilling period, keep the soil moist and between 70 to 75 degrees Fahrenheit for best germination. After seedlings sprout, quickly move them into your 4×14 pots containing well-drained potting soil. Fafard -2 is the Sun Gro pro mix that I recommend. It is one of our top blends for forestry. If planting in Black Gold, choose our Natural & Organic Potting Mix.
Water your trees regularly, especially during your hot, dry Texas summers. Once they are ready for orchard planting, I highly recommend amending your soil. Paw paws grow best in rich, moist, slightly acid loams. Sandy loams are fine as long as they have enough organic matter. The liberal addition of compost or peat moss will greatly increase the organic content of your sandy soil.
I also suggest that you visit the Lady Bird Johnson Wildflower Center’s informational page on paw paw trees. You may also consider contacting the Texas center for specific tips about growing these trees in Texas.
Happy paw paw growing!
Black Gold Horticulturist