The Date to Collect Ripe Hickory Nuts for Planting:
Of the dozen or so American hickories, shellbark and shagbark hickory trees have shown some promise as edible nut producers. These are the only two Carya species (with the exception of pecan or C. illinoensis) typically planted for nut production. All the following hickory nut suggestions apply to the collection and preparation of pecans.
Hickory flowers in the spring and completes nut maturity in early fall. Beginning as early as the first of September and continuing through November, various species of hickory nuts ripen and are ready for collection. Ripening dates can vary slightly from year to year and from state to state by as much as three to four weeks, making it difficult to use actual dates to determine maturity.
The best time to collect hickory nuts, either off the tree or from the ground, is when they begin falling - just that simple. Prime picking is late September through the first week in November, depending on the individual hickory tree species and its location within the United States. The hickory nut is perfect when the husks begin to split.
Collecting Hickory Nuts for Planting:
The height of the hickory nut crop in a forest canopy and the thick forest litter below can make it somewhat difficult for the causal collector to gather large numbers of nuts (although not impossible). Another challenge is harvesting nuts before wildlife does.
Another thing to remember is that nut availability is never an annual given. Good hickory crops (called mast) of all species are produced at intervals of 1 to 3 years so finding nuts can be a challenge on any given fall season.
With that in mind, find forest trees that are open grown with little forest underbrush. Yard trees or paved areas help in collecting where hickories exist in urban and suburban areas. Trees chosen in this way also make identifying the nut species easier. Always identify the tree and place tags or mark the bags so you will know what species you have collected.
Storing Hickory Nuts for Planting:
Storage tests with pecan and shagbark hickory have demonstrated that hickories are like most other nut/acorn species in that they should be dried to a low moisture content and refrigerated if not planted immediately.
To be specific, Carya nuts should be dried to below 10% moisture and stored at around 40°F. If stored in sealed containers the nuts should be able to retain good viability for 2 years before losing half to two-thirds of their ability to germinate after 4 years.
Put dried hickory nuts in a polyethylene plastic bag - a wall thickness of four to ten mils - with damp peat mix or sawdust. These bags are ideal for storing nuts since they are permeable to carbon dioxide and oxygen but impermeable to moisture. Close the bag loosely and store in the refrigerator at 40 degrees until planting time. Check nuts throughout the winter and keep just barely damp.
Some nut species need stratification, or a cold period of time to fully improve the germination process. It is suspected that the hickory needs very little cold over a full season but studies show that viability can be improved by soaking the nuts in water at 70°F for 64 hours.
Planting Hickory Nuts:
You can plant unrefrigerated nuts in the fall and let the winter season do what nature does - refrigerate. You can also spring-plant with stratified or cold treated seed or take a chance on unstratified seed.
For ground planting: Great results have been reported with fall seed sowing for hickory, but good mulching is necessary. Mulch should remain until germination is complete. Shading is generally not necessary, but hickory may profit from initial shade. Protection from rodents may be required for fall-sowings.
For container planting: After determining the proper time to plant as previously discussed, you should place nuts in loose potting soil in one-gallon pots or deeper containers. The tap root will grow quickly to the bottom of containers and root width is not as important.
Containers should have holes in the bottom to allow for drainage. Place hickory nuts on their sides at a depth of one half to one times the width of the nut. Keep the soil moist but not wet. Keep the "pots" from freezing.