Starting Tree Seeds Outdoors: A Simple Guide to Diverse Landscapes

Trees are the anchors of our landscapes. They enrich the soil, provide oxygen, offer shelter and food for wildlife, and deliver incredible seasonal beauty. My goal is to diversify our property by replacing invasive plants with a variety of beautiful, beneficial trees and shrubs.

In two of my more recent videos, I discussed planting over ten different types of tree and shrub seeds. While their growing requirements vary, the fundamental seed starting process is surprisingly simple, especially when you leverage the power the natural weather cycle.

This post summarizes the steps and specific requirements for each of the varieties I planted, providing you with a complete guide to start your own tree seedlings outdoors this season.

The First Step: Hydration and Preparation

Before any seed can germinate, it needs to break dormancy. For all the tree and shrub seeds covered here, the initial steps are very important:

1. 24-Hour Water Soak: Submerging the seeds in water for a full day helps to dissolve and wash away natural growth inhibitors and ensures the seeds are fully rehydrated. I use a fine sieve to drain and rinse the seeds after soaking to remove any tannins.
2. Pulp Removal: If you collect fruit seeds, like Ginkgo, you must remove the fruit pulp first. Word of advice: Use gloves or a tool (like a fork) to separate the seed from the fruit, as the pulp is notoriously smelly!

then…

Stratification: The Easy, Natural Method

Stratification is the process of exposing seeds to conditions (usually cold and moist) that mimic winter, breaking the final barrier to germination.

While you can use the popular “baggie in the refrigerator” method, I find it much easier and more effective to plant the seeds directly in pots and leave them outdoors.

This method allows the seeds to experience the natural cycles of freezing, thawing, and moisture that perfectly cue them when to sprout in the spring. And what’s great is you don’t use up space in the refrigerator! This method is also great for those of us who are busy and may have trouble going back and planting seeds you may have forgotten about in the dark cold recesses of the fridge.

Choosing Your Pots and Soil

• I use larger pots (for trees) filled with a mix of crushed leaves and pine needles on the bottom as filler, and fine bark shavings on top. This provides good drainage and structure.
• I plan to transplant seedlings into individual pots when they are about 6–8 inches tall, so grouping multiple seeds in a larger pot to start is very efficient. If seeds don’t germinate I don’t have a pot taking up valuable soil and space!

⚠️ A Note on Protection: If you have high rodent pressure (squirrels, chipmunks), a sturdy cover like hardware cloth is a must. While I use row cover to deter birds, it will not stop a determined rodent. My pots are in a location where the rodents typically aren’t.

Seed-By-Seed Starting Guide

Here are the specific requirements and key growing facts for the trees and shrubs I planted, including hardiness zones, sun, and water needs.

1. Red Maple (Acer rubrum)

Detail	Information
Sowing Depth	Lightly mixed into the top layer of the soil surface.
Stratification	Cold stratify (by planting outdoors).
Zone (Approx.)	3 – 9
Sun Needs	Full Sun to Partial Shade
Water Needs	Prefers moist, slightly acidic soil.

Comments: Red Maples offer outstanding fall color and native benefits. I’m excited to add more diversity alongside our native Sugar Maples. The seed viability for the varieties I sourced (Missouri/Tennessee) was excellent, with a 91% cut rate.

---

2. Japanese Maple (Acer palmatum)

Detail	Information
Sowing Depth	Surface sow, then lightly cover with a thin layer of soil.
Stratification	Cold stratify (by planting outdoors).
Zone (Approx.)	5 – 8
Sun Needs	Partial Shade (protect from intense afternoon sun).
Water Needs	Consistently moist, well-drained soil.

Comments: I collected these samaras (winged seeds) from my mom’s tree. While the wings can be pinched off before soaking, it’s completely optional. Soaking for 24-48 hours helps leach out the tannins which can inhibit germination. After germination, the seedlings can be easily separated into individual pots or one large container/bed.

---

3. Full Moon Maple (‘Osami’) (Acer japonicum)

Detail	Information
Sowing Depth	Mixed into the top layer of the soil mix.
Stratification	Warm stratify for 120 days THEN Cold stratify for 120 days.
Zone (Approx.)	5 – 7
Sun Needs	Partial Shade.
Water Needs	Consistently moist, well-draining soil.

More Info: This beautiful, non-native maple has a very complex stratification requirement. I am attempting to satisfy the cold period by planting it outdoors in winter, but it may require another cycle to complete the required warm/cold sequence. The viability cut rate from the purchased seeds was 71%.

---

4. Ginkgo (Ginkgo biloba)

Detail	Information
Sowing Depth	1 to 1.5 inches deep (about two times the seed depth).
Stratification	Cold stratify (by planting outdoors).
Zone (Approx.)	3 – 9
Sun Needs	Full Sun.
Water Needs	Moderate; tolerant of most soils once established.

Comments: Seeds were collected locally. The absolute most important step is pulp removal; the fruit smells terrible, so use gloves or a tool to extract the clean seed after soaking. Planting depth should be approximately 1-1.5 inches.

---

5. Red Buckeye (Aesculus pavia)

Detail	Information
Sowing Depth	1 to 2 inches deep.
Stratification	Cold stratify for 30 days. Fall sowing in mulch beds is preferred.
Zone (Approx.)	4 – 8
Sun Needs	Best in Afternoon Shade (understory tree).
Water Needs	Moderate; moist, well-drained soil.

Comments: One of my favorite small trees! They are excellent hummingbird magnets due to their red flowers. Since the seeds are large, planting them fresh in the fall is recommended to prevent dehydration that can occur during artificial stratification.

---

6. Black Gum (Tupelo) (Nyssa sylvatica)

Detail	Information
Sowing Depth	Approximately $3/4$ inch deep.
Stratification	Cold stratify for 90 days.
Zone (Approx.)	3 – 9
Sun Needs	Full Sun to Partial Shade.
Water Needs	Prefers wet to average, acidic soil.

Comments: A great native tree that provides some of the best burgundy and reddish fall color you can find. It shares similar soaking and stratification requirements as the maples. The germination cut rate was very high at 91%.

---

7. Sweet Gum (Liquidambar styraciflua)

Sweet gum seeds are rather small so I don’t soak these seeds at all.

Detail	Information
Sowing Depth	Sprinkle seed and chaff on surface, then give a very light covering of soil.
Stratification	Cold stratify (by planting outdoors). No soaking required.
Zone (Approx.)	5B – 10A
Sun Needs	Full Sun.
Water Needs	Medium; prefers moist, slightly acidic soil.

Comments: While the gumballs can be problematic, this is a very good tree for wildlife and spectacular fall color. The variety I collected grows in a columnar shape but most likely will not be true to the parent plant. Remember, no pre-soaking is necessary for these seeds, making them easy to plant directly.

---

8. Flowering Dogwood (Cornus florida)

Detail	Information
Sowing Depth	Lightly covered with soil.
Stratification	Cold stratify (by planting outdoors).
Zone (Approx.)	5 – 9
Sun Needs	Full Sun to Partial Shade.
Water Needs	Moderate; rich, well-drained soil.

Comments: Check berries for pests before planting. In the video below I actually found a maggot in the seed pulp which I removed. The red pulp must be fully removed, which is made easier by soaking the berries first. I recommend cleaning the seeds thoroughly after soaking, perhaps with a touch of dish soap, if pests are a concern.

---

9. Magnolia (Magnolia grandiflora example)

This works for multiple types of magnolias.

Detail	Information
Sowing Depth	Plant lightly into soil.
Stratification	Cold stratify (by planting outdoors).
Zone (Approx.)	7 – 9 (Varies by species)
Sun Needs	Full Sun to Partial Sun
Water Needs	Moderate, prefers rich, moist, acidic soil.

Comments: Similar to Dogwoods, the fleshy outer coating (the red pulp) must be removed before planting, typically after a 24-hour soak to soften it. I currently have about 62 Southern Magnolia seeds planted.

---

10. Red Osier Dogwood (Cornus sericea)

Detail	Information
Sowing Depth	Approximately $1/4$ inch deep.
Stratification	Cold stratify for 90 days.
Zone (Approx.)	2 – 7
Sun Needs	Full Sun to Partial Shade.
Water Needs	High; thrives in wet areas and moist soil.

Comments: A fantastic shrub for winter interest, famous for its bright red stems. It is very easy to grow from seed using the natural cold stratification method. Prune it back periodically to encourage new, colorful stem growth.

---

11. American Beautyberry (Callicarpa americana)

Detail	Information
Sowing Depth	Mixed into the surface of the soil.
Stratification	Cold stratify (beneficial, but not always required).
Zone (Approx.)	5 – 8
Sun Needs	Full Sun (for best fruiting) to Light Shade.
Water Needs	Low to Moderate; very drought-tolerant once established.

Comments: The seed collection for beautyberry is easy, just pluck the berries and soak them to remove the pulp. I always make sure to leave plenty of berries on the plant for the local wildlife. Planting them outdoors ensures they benefit from natural stratification.

What’s Next?

With the seeds planted and covered, all that’s left is to let nature take its course. I’ll give the pots a good, deep watering and then wait for the signs of life in the spring! Check out the video content below for more detail and don’t forget to subscribe!

Prepping Tree Seeds in the Fall (Video)

6 More Tree Seeds to Start in December (Video)

Make sure you are subscribed to Growing The Home Garden to catch the spring update videos to see which of these new trees and shrubs successfully germinate!