The hazelnut tree, a member of the genus Corylus, is prized globally for its nutritious nuts, often called filberts, and its attractive, multi-stemmed growth habit. Propagating this valuable plant directly from the nut, or seed, is a slow but satisfying process that connects the grower to the tree’s natural life cycle. Hazelnuts possess a deep, natural dormancy, meaning the seed must be tricked into believing a winter has passed before it will sprout. Growing from seed can result in unpredictable genetic variation, which often leads to low germination rates compared to other propagation methods.
Selecting and Preparing the Nut
The first step is securing nuts that are genetically viable and capable of germination. Use raw, fresh nuts that have not been dried, roasted, blanched, or treated with preservatives, as heat and processing destroy the embryo inside. While both European hazelnut (Corylus avellana) and American hazelnut (Corylus americana) are popular choices, ensure the nuts are sourced from a reputable supplier or collected directly from a healthy tree.
To test for viability, perform a simple float test by submerging the nuts in water. Discard any nuts that float, as they are likely hollow, damaged, or dried out. Before stratification, lightly scarify the hard outer shell of the nut with sandpaper or a file. This abrasion helps water penetrate the seed coat, which is necessary to initiate germination during the cold, moist period.
The Stratification Process
Stratification is mandatory for hazelnut seeds, as it mimics the cold, damp conditions of a natural winter required to break dormancy. This cold, moist stratification typically needs to last for 90 to 120 days, or three to four months. The ideal storage temperature is maintained just above freezing, specifically within the range of 34°F to 41°F (1°C to 5°C), which is easily achieved in a household refrigerator.
To prepare the nuts for storage, mix them with a slightly moistened medium such as peat moss, vermiculite, or horticultural sand in a plastic bag or container. The medium should feel damp like a wrung-out sponge, not wet, as excess moisture encourages mold and fungus growth. Peat moss is often preferred because its natural anti-fungal properties help suppress mold during the long stratification period.
Check the stored nuts periodically to ensure the medium remains slightly damp and to allow air exchange. Consistent refrigeration is necessary for the entire duration; if the temperature drops below 32°F (0°C), stratification stops. After the required period, small white roots, known as radicles, may emerge from the shell, indicating the seed is ready to be planted.
Planting the Germinated Seed
Once the hazelnut seed has successfully sprouted a radicle, it is ready to transition to a growing medium, typically in early spring after the threat of hard frost has passed. Planting the nuts into temporary pots before moving them to the ground is recommended, as this allows for better protection and management during the vulnerable seedling stage. Choose a container that is at least six inches deep to provide ample room for the young taproot to grow.
A well-draining soil mix is necessary, as hazelnuts will not tolerate standing water, which can lead to root rot. A good composition is a loamy soil rich in organic matter, or a blend of equal parts garden soil, peat, and sand to ensure aeration. When planting the sprouted nut, orient the seed so the fragile radicle is pointing downward into the soil.
The nut should be planted at a shallow depth, typically one to two inches beneath the soil surface. After planting, provide a deep, gentle watering to settle the soil around the nut. Place the pot in a location that receives either full sun or partial shade. This transition to a warmer environment encourages the shoot, or hypocotyl, to emerge from the soil.
Protecting and Caring for the Seedling
The first year is the most tenuous period for a young hazelnut sapling, requiring attentive care to ensure its survival against environmental stresses and common threats. Consistent watering is necessary, especially during the first growing season when the root system is establishing itself. The soil should be kept evenly moist but never saturated, as waterlogged conditions are highly detrimental to young hazelnut roots.
Protecting the tender seedling from wildlife is an immediate concern, as small rodents, squirrels, and deer view the young plant as a potential meal. A protective barrier, such as a wire cage, hardware cloth cylinder, or a mesh tree guard, must be placed around the seedling immediately after planting to deter browsing and digging. These barriers should be tall enough to prevent deer from reaching the leaves and wide enough to allow for a few seasons of growth.
Hazelnut seedlings typically exhibit slow growth in their first year, often reaching only 12 to 18 inches in height, which requires patience from the grower. While a light application of a balanced, slow-release fertilizer can be used, rich soil often provides sufficient nutrients for the initial growth phase. Maintaining a layer of mulch around the base of the seedling helps regulate soil temperature, retain moisture, and suppress competing weeds without touching the delicate stem.