Set-and-Forget Guerilla Gardening: Planting Nut Trees to Transform Neglected Spaces

One effective guerilla gardening technique is the “set-and-forget” method, which involves discreetly planting nut tree seeds in suitable locations and leaving them to grow naturally over time. Nut trees are particularly well-suited for this approach because they look much like regular street trees as they grow, and can take many years before they become productive. By the time these trees start producing nuts and people realize what they really are, they will already have grown to become large, well-established trees that seamlessly blend into the landscape.

This method was inspired by the late Bill Mollison, cofounder of permaculture, who shared this simple yet impactful practice. He would carry a pocketful of nuts and, whenever he found a suitable spot, would quietly press a nut deep into the soil with his finger before moving on. Over the following decades, these casually planted seeds would grow into mature, nut-bearing trees, providing free food to the community. Mollison’s approach emphasized the power of small, intentional actions in transforming landscapes and supporting local ecosystems.

Suitable Nut Trees for Guerilla Gardening Seed Planting

1. Black Walnut (Juglans nigra)

• USDA Zones: 4-9
• Growing Requirements: Black walnuts prefer deep, well-drained loamy soils but can tolerate a range of soil types. They require full sun and need plenty of space to accommodate their large size, as they can grow up to 100 feet tall.
• Pollination: Black walnuts are monoecious, meaning they have both male and female flowers on the same tree, but they are not self-pollinating. For optimal nut production, it is recommended to plant more than one tree to ensure cross-pollination.
• Years to Production: Trees grown from seed typically take 10-15 years to start producing nuts​

2. Chestnuts (Castanea species)

• USDA Zones: 4-8
• Growing Requirements: Chestnuts prefer well-drained, slightly acidic soils. They need full sun and are generally drought-tolerant once established. Chestnuts can grow 60-100 feet tall, depending on the species.
• Pollination: Chestnuts are also monoecious, but they require cross-pollination from a different variety of chestnut tree for optimal nut production, so planting at least two trees is essential.
• Years to Production: Seed-grown chestnuts typically take 5-7 years to start producing nuts​.

3. Hazelnuts (Corylus species)

• USDA Zones: 4-8
• Growing Requirements: Hazelnuts thrive in well-drained, loamy soils but can tolerate a range of soil types. They prefer full sun to partial shade and can be grown as shrubs or small trees, reaching 10-20 feet in height.
• Pollination: Hazelnuts are wind-pollinated and are usually self-incompatible, meaning they require a different variety nearby for cross-pollination to set nuts. Plant several seeds around 3m (10 feet) apart to ensure pollination.
• Years to Production: Hazelnuts grown from seed typically take 4-6 years to start producing nuts.

4. Hickory (Carya ovata)

• USDA Zones: 4-9
• Growing Requirements: Shagbark hickories prefer deep, well-drained soils with a neutral to slightly acidic pH. They require full sun and can grow up to 80 feet tall, with a spread of 50 feet.
• Pollination: Hickories are monoecious but benefit from cross-pollination with other hickory trees, especially for better nut production.
• Years to Production: Hickories are slow-growing and may take 10-15 years to start producing nuts when grown from seed .

5. Pecans (Carya illinoinensis)

• USDA Zones: 5-9
• Growing Requirements: Pecans thrive in deep, well-drained soils with full sun exposure. They are best suited for areas with long, hot summers, as they require a lengthy growing season to mature nuts.
• Pollination: Pecans are monoecious and wind-pollinated, but they require cross-pollination from a different variety to set a good crop. Planting more than one variety is recommended, so plant more than one seed.
• Years to Production: Pecans grown from seed may take 10-15 years to begin producing nuts .

6. Macadamia (Macadamia integrifolia and Macadamia tetraphylla)

• USDA Zones: 9-11
• Growing Requirements: Macadamia trees require well-drained, slightly acidic soils and thrive in warm, humid climates. They need full sun and are sensitive to frost, making them ideal for subtropical to tropical regions, such as Queensland and northern New South Wales in Australia. They do not tolerate winds and prefer protected locations.
• Pollination: Macadamias are partially self-pollinating, but planting multiple trees can significantly increase nut yield due to better cross-pollination.
• Years to Production: Macadamias take longer to mature, typically 7-10 years from seed to start producing nuts .

These nut trees, while varying in their growing requirements and time to production, are all excellent options for long-term guerilla gardening projects. By choosing species well-suited to the local climate and understanding their specific needs, it’s possible to successfully establish these trees with minimal maintenance, contributing to urban greening and food security for the community.

Where to Gather Nut Tree Seeds for Guerilla Gardening

When it comes to sourcing viable seeds for guerilla gardening, gathering them directly from existing, mature trees is often the best option. This method not only increases the likelihood of successful germination but also ensures that the seeds are well-adapted to the local environment.

Gathering Seeds from Existing Trees

Why It’s Effective:

• Local Adaptation: Seeds collected from trees that are already thriving in the local area are more likely to be adapted to the specific climate, soil, and environmental conditions of that location. Using locally adapted seeds increases the chances that the seeds will germinate and grow successfully.
• Fresh Viability: Seeds harvested directly from trees are going to be fresher and have a higher viability rate compared to store-bought nuts, which may have been processed or stored in less-than-ideal conditions, reducing their viability.
• Cost and Sustainability: Collecting seeds from nature is a cost-free method that aligns with the sustainable practices of guerilla gardening. It also allows for greater genetic diversity if you gather seeds from different trees and locations.

How to Collect, Prepare, and Plant Nut Tree Seeds

The steps below explain how to successfully grow nut trees from seeds, by collecting the seeds at the right time, preparing them for planting or storage, stratifying them if necessary, and correctly planting them into the ground.

1. Harvest Timing

The first step in growing nut trees from seeds is collecting the seeds at the right time. Nut tree seeds, such as those from walnuts, chestnuts, hazelnuts, macadamias, pecans, and hickories, should be harvested during the appropriate season when they are fully mature but before they are naturally dispersed or consumed by wildlife.

• Walnuts and Chestnuts: These nuts typically drop to the ground in mid to late autumn when they are ready for harvest. Collect them promptly to avoid loss to animals or decay.
• Hazelnuts: Hazelnuts are usually harvested in early to mid-autumn. They can be collected directly from the ground after they fall or by gently shaking the branches to dislodge the nuts.
• Hickories: Hickory nuts ripen from late autumn through early winter, depending on the species. They should be harvested when the husks turn brown and the nuts fall from the tree. Like pecans, hickory nuts should be collected promptly from the ground to ensure quality.
• Pecans: Pecan nuts are generally ready for harvest in mid to late autumn, once the husks split open, revealing the mature nuts inside. They often fall to the ground naturally, and it’s best to collect them quickly to prevent spoilage or loss to wildlife.
• Macadamias: Macadamias ripen from late autumn through early winter. The nuts naturally fall to the ground when ripe, indicating they are ready for collection. It’s crucial to gather the fallen nuts regularly to prevent spoilage or damage from pests. When preparing macadamia seeds for planting, do not remove the hard shell. Instead, soak the seeds in water for 24-48 hours to soften the shell. Light scarification can help with germination, but care must be taken not to damage the seed inside. After soaking, plant the seeds with the shell intact about 1 inch deep in well-draining soil. Position the micropyle (the small white spot on the shell) to the side to aid proper root development. Macadamia seeds can take 1 to 6 months to germinate, so maintaining consistent moisture and warmth is essential during this period.

2. Immediate Planting or Storage: Husk Removal and Proper Drying

Whether you plan to plant nut tree seeds immediately or store them for later use, it is essential to first remove the husk. The husk is the outermost fleshy or fibrous layer surrounding the nut. For example, in walnuts, this husk is green and thick when freshly harvested. Removing the husk is crucial because it retains moisture, which can lead to mold and decay, potentially compromising the seed’s viability regardless of whether you intend to plant or store the seeds.

After the husk is removed, the shell of the nut remains intact. The shell is a hard, protective layer that encases the seed—the edible part of the nut. Unlike the husk, the shell should not be removed because it protects the seed during the germination process and helps regulate moisture levels, which are critical for successful germination.

How to Properly Dry Nut Tree Seeds

Once the husk is removed, it is important to dry the seeds thoroughly before either storage or planting—except for macadamias.

Macadamia seeds should not be dried before planting; instead, soak them in water for 24-48 hours to soften the shell and aid in germination. If storing macadamia seeds for future planting, keep them in a cool, moderately humid environment, such as a refrigerator,, and kept in a breathable container to maintain viability. The seeds should be planted within 6 to 12 months, as their ability to germinate decreases significantly after this period.

For other types of nut tree seeds, follow these drying steps:

1. Spread the Seeds: Lay the seeds out in a single layer on a flat surface, such as a tray or screen, in a well-ventilated area. Avoid stacking them to ensure even drying.
2. Air Drying: Allow the seeds to air dry for several days to a week, depending on the humidity and temperature of the environment. The drying area should be cool, dry, and away from direct sunlight to prevent overheating, which could damage the seeds.
3. Turn the Seeds: If possible, turn the seeds periodically to ensure all sides dry evenly. This helps to prevent any moisture from being trapped, which could lead to mold growth.
4. Check for Dryness: The seeds should feel dry to the touch and no longer have a soft or damp texture. For walnuts and similar nuts, the shell should be hard and free of any moisture.
5. Storage After Drying: Once the seeds are completely dry, they can be stored in a cool, dry place, such as a sealed container kept in a refrigerator, to maintain their viability until planting.

Immediate Planting or Storage

• Immediate Planting: If you plan to plant the seeds right away, they can be sown directly into the soil. Make sure that the seeds are completely free from any husk and are thoroughly clean and dry before planting to promote successful germination.
• Storage: If you are not planting the seeds immediately, proper storage is vital to maintain their viability. Store the dried seeds in a cool, dry place, such as a sealed container in a refrigerator. This environment helps preserve the seeds until you are ready to plant them, reducing the risk of mold and decay.

3. Stratification

For many nut tree seeds, particularly those from temperate climates, stratification is essential to break seed dormancy and promote germination. There are two primary methods to achieve this: Outdoor Stratification and Refrigerator Stratification.

1. Outdoor Stratification

• Suitable for: Walnuts, Pecans, Hickory Nuts, Hazelnuts, Chestnuts
• Process:
  • Timing: In regions with naturally cold winters, seeds can be planted directly in the ground during the fall.
  • Preparation: Sow the seeds about 2-5 cm (1-2 inches) deep in well-drained soil.
  • Protection: Cover the planting site with mulch to protect the seeds from extreme conditions and to help maintain moisture levels.
  • Outcome: The seeds will naturally undergo the cold stratification process over the winter months. This cold period will break dormancy, allowing the seeds to germinate in the spring when temperatures warm up.

2. Refrigerator Stratification

• Suitable for: Walnuts, Pecans, Hickory Nuts, Hazelnuts, Chestnuts
• Process:
  • Prepare a Moist Medium: Mix damp sand, peat moss, or vermiculite. The medium should be moist but not overly wet.
  • Container: Place the seeds in a sealable plastic bag or a container filled with the moist medium. Ensure the seeds are surrounded by the medium to keep them moist.
  • Refrigeration: Store the container in a refrigerator set to temperatures between 1°C and 5°C (33°F to 41°F). The duration depends on the type of seed:
    • Walnuts, Pecans, and Hickory Nuts: Stratify for about 90 to 120 days (3 to 4 months).
    • Hazelnuts and Chestnuts: Stratify for 60 to 120 days (2 to 4 months).
  • Post-Stratification: After this period, the seeds are ready to be planted in the soil, where they will begin to germinate as temperatures rise.

Macadamias: Exception

• No Stratification Required: Unlike the other nuts mentioned, macadamia seeds do not require stratification. Instead, soak them in water for 24-48 hours, then plant them directly with the shell intact.

4. Planting

When you’re ready to plant, ensure that the seeds are placed at the correct depth in the soil.

• Planting Depth: Generally, nut tree seeds should be planted about 2.5-5 cm (1-2 inches) deep, depending on the size of the nut. This depth helps protect the seeds from being disturbed by animals and maintains the moisture levels necessary for germination.
• Site Selection: Choose a planting site with well-drained soil and adequate sunlight exposure appropriate for the species. Walnuts, chestnuts, pecans, and hickories prefer full sun for optimal growth and nut production. While these trees can tolerate some partial shade, they generally perform best in locations with at least 6 hours of direct sunlight daily. Macadamias, on the other hand, prefer full sun but can also tolerate partial shade, making them more versatile in varying light conditions. Hazelnuts are more shade-tolerant than the other species and can thrive in partial shade, making them suitable for areas with limited direct sunlight.
• Watering:
  • Initial Watering: After planting, water the seeds thoroughly to help settle the soil around them and provide the necessary moisture for germination.
  • Ongoing Moisture: Keep the soil consistently moist but not waterlogged during the germination phase. Depending on your local climate, you may need to water the seeds periodically, especially if rainfall is infrequent. Avoid overwatering, as this can lead to rot or fungal issues.
• Mulching: Adding mulch around the planting area can help retain soil moisture and regulate temperature, which is particularly beneficial in drier climates or during periods of low rainfall.

By following these steps—harvesting at the right time, preparing seeds properly through husk removal and stratification, and planting with attention to depth, moisture, and site conditions—you can successfully grow nut trees from seeds. These practices are rooted in agricultural science and provide the best chance for successful germination and healthy tree growth.

Why Store-Bought Edible Nuts Are Not Ideal for Planting

• Processing: Most store-bought nuts are processed (e.g., roasted or shelled), which destroys their ability to germinate. Raw, unprocessed nuts such as walnuts or hazelnuts that are still in their shells might germinate, but the success rate is usually low due to storage conditions.
• Unknown Viability: The storage and handling of edible nuts before they reach the store often reduce their viability. They may have been exposed to drying agents, heat, or other conditions that make them less likely to sprout.

For the most reliable results, gathering seeds directly from local, producing trees is the best strategy for guerilla gardening. This approach not only ensures higher viability but also supports the growth of plants that are well-suited to your specific environment.

Does It Matter If Nut Trees Are Not “True to Seed”?

In the context of growing productive trees, being “true to seed” means that the seed will produce a tree that is genetically the same as the parent tree in its growth habit, appearance, fruit quality, fruit flavor/taste, productivity, and final growth size.

This is important in commercial operations, where specific nut tree varieties are grown because uniformity in crop quality is essential for marketability and profitability. The nuts produced have to be of a consistent size, quality and taste. This is why commercially grown nut trees are often propagated through grafting as this ensures that the new trees are genetically identical in variety to the parent tree.

When trees are not true to seed, there is natural genetic variation, and the nuts produced can be quite different from the parent variety. However, for guerilla gardeners, the importance of trees being true to seed is less critical, as the emphasis is on environmental benefits and long-term sustainability rather than uniformity of the harvest. The goal is often more about establishing resilient, low-maintenance plants that contribute to urban greening and provide future food sources. Even if the nuts produced may vary in size, flavor, or shell thickness, the primary objective—creating self-sustaining green spaces—is still achieved.

True to Seed Nut Trees:

• Black Walnut (Juglans nigra): Black walnuts are generally true to seed, meaning trees grown from seeds tend to produce nuts similar to the parent tree, though some variability can occur.
• Hickory (Carya ovata): Hickories also tend to be true to seed, with offspring typically retaining desirable characteristics from the parent tree.

Not True to Seed Nut Trees:

• Chestnuts (Castanea species): Chestnuts, especially hybrids, are not true to seed. Offspring can vary widely in nut quality and tree characteristics.
• Hazelnuts (Corylus species): Hazelnuts are not true to seed; trees grown from seeds often show considerable variation in nut size, flavor, and growth habits.
• Pecans (Carya illinoinensis): Pecans are highly variable when grown from seed, with significant differences in nut size, flavor, and production quality.
• Macadamia (Macadamia integrifolia and Macadamia tetraphylla): Macadamia trees are not true to seed, and there can be significant variability in nut production and quality.

Emulating Nature in Permaculture, Learning from Squirrels

In permaculture, the goal is to create sustainable, self-sufficient systems by observing and mimicking natural processes that have evolved over millions of years. By working in harmony with nature and utilizing these natural processes, we can develop agricultural practices that require less energy, fewer resources, and minimal human intervention, all while maintaining the ecological balance.

An example of this is how squirrels contribute to forest regeneration by burying nuts that often grow into new trees, helping promote biodiversity and sustain ecosystems. In permaculture, we can adopt a similar “set-and-forget” approach by planting nut seeds in suitable locations, and allowing them to grow naturally over time, much like squirrels do. Just as squirrels plant seeds that eventually grow into mature trees, we can strategically plant seeds that will develop into resilient, productive trees, contributing to long-term sustainability and biodiversity.

The Ecological Role of Squirrels in Nut Tree Planting

Squirrels, such as the Eastern Gray Squirrel (Sciurus carolinensis), play a vital role in the propagation of nut trees in temperate forests by burying nuts to store them as a winter food reserve. Many of these buried nuts are never retrieved, and left in the ground they germinate and grow into new trees.

This seed-burying behavior helps disperses seeds over a wide area, maintaining genetic diversity and ensuring the nuts are buried at an ideal depth for germination. The squirrels’ natural habits support forest regeneration and biodiversity, making them key agents in sustaining these ecosystems. Their actions help maintain healthy forests, and illustrate how animal behavior can positively influence ecosystems.

In conclusion, the “set-and-forget” approach in guerilla gardening allows us to discreetly plant nut tree seeds in urban spaces, letting nature take its course. Over time, these trees grow into mature, nut-bearing trees, providing food, shade, and beauty to neglected areas. By emulating natural processes and selecting trees suited to the local climate, we can make a lasting impact on urban landscapes with minimal effort. This method, inspired by permaculture principles, highlights how small, intentional actions can lead to significant environmental benefits, transforming neglected spaces into thriving ecosystems.