Growing Chestnuts
Introduction to Growing American Chestnuts
This page is dedicated to growing American chestnut trees, Castanea dentata. However, most of these techniques apply to growing any species of chestnut tree.
The American chestnut is considered functionally extinct due to the devastating impact of a chestnut blight that reached North America in the late 1800’s. (Read History of the American Chestnut.)
The mission of The American Chestnut Foundation is to restore the American chestnut tree to its native range in eastern North America, with the primary goal of developing disease-resistant American chestnut trees for restoration plantings. Thank you for helping restore the American chestnut!
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Seed in pots
Seed in ground
Seedling in pots
Seedling in ground
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Resources
Video Library
Why Grow Chestnuts
What Kind of Chestnuts Should I Grow?
Where to Get Chestnuts
Storing & Preparing Seed
Planting Seeds in Pots
Planting Seeds in the Ground
Planting Seedlings in Pots
Preparing Seedlings to Plant in the Ground
Planting Seedlings in the Ground
Caring for Plantings
Resources
Printable Downloads
- Planting American Chestnut in Pots – 2-page fact sheet by TACF
- Growing Chestnuts – 4-page fact sheet by TACF
- Planting and Growing Chestnut Trees – 15-page manual by the PA Chapter of TACF
- Best Management Practices for Reintroducing American Chestnuts to Your Property – 8-page guide by TACF
Web Pages
- American Chestnut Fact Sheets -TACF
- Growing Chestnuts – Route 9 Cooperative
- Chestnut Magazine archives – TACF
- Chestnut Growers of America – trade association for commercial growers
- Cooperative Extension – for local growing advice
Video Library
How to Grow American Chestnuts
How to Get, Grow, & Manage American Chestnuts
Site Selection and Planting American Chestnut
Chestnut Planting Tutorial
Chestnut Pests and Pathogens
Cold Tolerance in American Chestnuts
Chestnut Harvest and Storage
Chestnut Growing Tutorials
(Doug McClane VT-NH)
Why Grow American Chestnuts?
Restoring a Foundation Species
The American chestnut was once an important tree in the forests of eastern North America. It was among the largest, tallest, and fastest-growing trees and provided bountiful resources for wildlife, from insects to bears. It also provided resources for many generations of Indigenous peoples and European settlers as both a food source and as rot-resistant lumber. In the late 1800s, an imported fungus called Cryphonectria parasitica caused a chestnut blight that spread across the native range, killing nearly 4 billion trees. Today, many root systems continue to survive and send up shoots which eventually succumb to the blight. (Read History of the American Chestnut.) Simultaneously, a fungus-like organism called Phytophthora cinnamomi, likely transported to North America a hundred years before the blight, was killing American chestnuts primarily in the southern part of the range. The disease it causes, called ink rot or Phytophthora root rot, kills the entire tree by killing the roots. The American Chestnut Foundation (TACF) is working to develop an American chestnut tree with resistance to both pathogens and to restore it to the native range. (Read more About TACF.) You can help support this ambitious mission by growing American chestnut trees.
What Kind of American Chestnuts Should I Grow?
Wild-Type
What is a wild-type American chestnut?
A wild-type American chestnut tree has not been intentionally hybridized with other chestnut species or genetically modified. These are sometimes referred to as “pure” American chestnuts but it’s important to remember that all nine species of chestnut worldwide (the genus Castanea) can hybridize with each other in the wild and some wild trees may be natural hybrids.
Why grow wild-type American chestnuts?
Growing wild-type American seedlings helps preserve genetic diversity for future breeding and diversification and provides a wonderful learning experience for you to grow, care for, and maintain American chestnut trees on your unique site. While wild-type American chestnuts are not resistant to the blight, they can thrive for many years and produce seed (nuts) for harvest and consumption.
Genetically Improved
What is a genetically improved American chestnut?
An improved tree has been genetically altered through either traditional breeding methods (such as hybridizing with other chestnut species and backcrossing), or using biotechnology methods to insert genes from other chestnut species (cisgenics) or from other plant species (transgenics). Some improved trees may combine both biotech and traditional breeding methods.
Why grow genetically improved American chestnuts?
The benefit of growing improved American chestnuts is that they generally have higher blight resistance than wild-type American chestnuts. However, at this point, there are no American chestnut trees that are 100% blight-resistant. Currently, all improved American chestnut trees have intermediate levels of blight resistance and are products of ongoing research, making them difficult to acquire. Transgenic trees have not yet passed federal deregulation and backcross seeds are typically only available in small quantities.
Where To Get American Chestnut Trees
Getting Chestnuts From The American Chestnut Foundation
The two types of plant material available to current members of The American Chestnut Foundation are wild-type American chestnut seedlings and hybrid American chestnut seeds with intermediate levels of blight resistance. Both are only available in the spring. See the Seeds & Seedlings page for more info.
Some TACF chapters offer seed or seedling sales and offerings to their current chapter members at various times of the year. Become a member of TACF to receive email updates from your local chapter about offers.
Can I get Chestnuts Shipped to my State or Country?
Seedlings from TACF’s Annual Wild-Type Seedling Sale are only shipped within the United States to states east of the Mississippi River. This helps prevent the spread of pathogens such as chestnut blight and Phytophthora root rot outside the native range. However, seeds that ship to TACF’s Seed Level Members are soaked in a hydrogen peroxide or bleach solution to kill external pathogens and can be shipped to states west of the Mississippi. No seeds will be shipped to California, Oregon, or Washington, nor outside the contiguous United States, due to state agricultural regulations.
Bareroot Wild-Type
American Chestnut Seedlings
Become a member at any level to receive access to participate in TACF’s Annual Wild-Type American Chestnut Seedling Sale in March. Learn more.
Hybrid American Chestnut Seeds
Become a Seed Level member to receive the annual gift of hybrid American chestnut seeds mailed to you every spring. Learn more.
Getting American Chestnuts From Commercial Nurseries
As a nonprofit, TACF does not make recommendations about where to obtain American chestnut seeds or seedlings because it cannot vouch for the authenticity of the plant material nor the practices of a private business. TACF strongly recommends verifying that any seeds you purchase are soaked in a solution to prevent the spread of blight and other contagions, especially if they come from the native range. If you are looking for species other than American chestnut, this PDF from the CT Agricultural Experiment Station has a list of chestnut growers, most of which sell Asian and European hybrid varieties.
Storing and Preparing American Chestnut Seeds for Planting
Cold Stratification
If you’re a first-time grower and wondering what a chestnut seed is, it is the nut itself! Chestnut seeds need a period of cold stratification (34-40°F is optimal) that lasts 60-90 days to germinate efficiently. Beyond this time, they should be kept cold until you are ready to plant. The vegetable crisper drawer in your refrigerator is usually a good option for providing the right conditions; however, watch out for storing chestnut seeds with certain fresh fruit – the ethylene produced by the fruit can cause the chestnuts to ripen too quickly. Chestnuts also need to be kept damp. This can be accomplished by storing seeds in a variety of pre-moistened media inside a ziploc bag. Peat is the standard, however, sphagnum moss, coarse perlite, or coarse vermiculite are all good alternatives. No matter the media you choose, it should be at a moisture content where no water drips out when you squeeze it in your hand. The radicle (young root) will likely emerge during cold storage. Once this happens, avoid moving or disturbing the nuts since the radicle is fragile.
If you receive seeds from The American Chestnut Foundation as a Seed Level Member then they will already have been cold stratified and are ready for planting. If you’re not ready to plant immediately, leave them sealed in the Ziploc bag in the refrigerator until planting time to keep them from sprouting, to reduce mold, and to keep them from drying out.
Planting American Chestnut Seed in Pots
Storing Chestnut Seeds
If you receive or collect your seeds before planting time and need to store them, see Storing and Preparing American Chestnut Seeds for Planting above.
Planting Date
Planting American chestnuts in pots is a great way to prep your chestnut trees before spring planting. Nuts should remain in cold storage until at least January. In general, you want to start your chestnuts in pots about 2-3 months before your area is ready for spring planting.
Planting Container
American chestnuts have long tap roots that need plenty of room to grow, so use a container that is much deeper than it is wide. If you would just like to get a jump on spring and plant your tree outside once the weather is warm enough, a smaller pot is fine. We recommend a container 10” deep or more, like the Stuewe Deepot D40. You can even use something like an old milk or orange juice carton (make sure to poke some drainage holes in the bottom). If the tree will remain in the pot for most of the year, or longer, a larger pot is more appropriate. In these cases, a pot like the Stuewe TreePot or large 1-2 gallon container will be better suited for longer-term storage.
Planting Mix
A soilless planting mix provides good drainage and a weed-free germination environment for your chestnuts. Soilless planting mixes tend to include a lot of peat moss, which can be difficult to get wet. It is often easier to wet the planting mix in a larger container so you can work the water in by mixing (think kneading dough). Remember that American chestnuts do not like to be too wet, so keep this in mind when choosing a planting mix. A simple mix of 1/3 each peat moss, perlite, and vermiculite is a great high-drainage mix that many chestnut growers use. This mix does not hold too much moisture, so if you forget to water your trees regularly you should look for a mix that holds a little more moisture, like Sun Gro Metro-Mix 560 Coir.
Planting the Seed
Fill a pot with damp planting mix, tamp down, and then poke a hole in the center with your finger or a hand spade. Often chestnuts will begin to sprout in cold storage so gently work the radicle (young root) into the hole until the nut is just below the soil surface. American chestnuts should be planted shallowly – a half-inch to one-inch deep. Do not break the radicle when you plant (this may kill the seed), and make sure you position the nut so that the pointed end, where the radicle comes out, is facing sideways. (NOT UP OR DOWN!) If the radicle has emerged at an odd angle, the point of the nut can face down into the pot, but never plant with the point facing up. Place your newly potted nut in a warm, sunny location. It should sprout within a week or two.
Seedling Care
Water your chestnut sparingly and allow the pot to dry out some between waterings. If the planting mix stays too wet, the nut may rot before it sprouts. Once sprouted, the seedling will need more water so adjust as needed. And of course, keep an eye on the temperatures. Water needs increase as temperatures increase and the winter sun can be warmer than you might expect. As with caring for any living thing, vigilance is the key so check your seedling regularly. Most issues can be remedied if caught quickly.
Planting Outside
When you are ready to plant your seedling outside, remember that it will be much farther along in its development than if it had sprouted naturally and should be planted outside after risk of frost. Also remember that the seedling is accustomed to the protected environment inside and needs to slowly acclimate to conditions outside. This process is called “hardening-off ” and should take at least two weeks. (Read more in the Preparing Seedlings section) Transplanting can be stressful on a plant, so properly hardening-off your seedling will improve the odds for success. A final tip – remove the remnant nut from the base of the seedling. At this point the seedling has used all the nutrients it needs from the nut, but the nut can still be attractive to rodents and other wildlife.
Planting American Chestnut Seed in the Ground
(Direct Sowing)
Storing Chestnut Seeds
If you receive or collect your seeds before planting time and need to store them, see Storing and Preparing American Chestnut Seeds for Planting above.
What Makes a Good Planting Location?
Well-drained soil is very important. Dry, sandy, gravelly, or loamy soils are good. Avoid clay soils or those that retain water. A generous amount of topsoil will result in better growth; however, chestnuts can generally tolerate relatively poor sites. Avoid planting over ledges or in compacted soils – the root system needs room to grow. The pH of the soil should be slightly acidic, between 4.5 and 6.5. You can find the pH of your soil by submitting a sample to a soil testing lab, available through most Land-Grant Universities. Soil test results from a lab will include soil pH, as well as an analysis of other important nutrients and fertilization recommendations.
Chestnut is intermediately shade tolerant. For fast growth and flower production, trees need full sun. They will tolerate shade, but will grow slowly in low-light environments and will not flower or reproduce.
Soil test results from a soil testing lab will include soil pH, as well as analysis of other important nutrients. Soil tests are highly recommended.
A wire cage can provide good protection from wildlife. The cage shown here was constructed of welded wire garden fencing, zip ties, and a hardwood stake.
Direct Sowing Chestnuts Outside
Chestnuts may be direct-sown outside with success. The same general rules for planting seed in pots apply to direct-sowing: plant chestnuts no more than ½ -1” deep, be careful to not break the radicle, and plant the seed so the radicle or pointed end is facing down or sideways. Chestnuts are a tasty food source for wildlife and it is important to protect the nuts from predation, especially before they sprout. A tree shelter, cage, or other protective device is a good idea. Tree shelters are also beneficial for transplanted seedlings (see Wildlife Protection, below).
When to Plant
Direct-sown chestnuts are usually planted in the spring but may be planted in the fall if good wildlife protection is in place. For spring planting, wait until the soil can be worked and the major risk of a hard frost has passed.
Soil Additives
Many growers plant chestnuts into a mixture of soilless potting mix (similar to recommendations for sowing in pots) and a small amount of native forest soils. The soilless potting mix provides a weed-free germinating environment for direct sowing. Adding a handful or two of forest soil, collected from under a pine or oak tree, may also be beneficial. Forest soils often contain beneficial mycorrhizae that can help make the chestnut’s root system more efficient. (Mycorrhizae are fungi typically found in forest soils but may be deficient in field soils.)
Spacing
Chestnuts can be planted at a variety of spacings, depending on the goal of the planting, but no matter the spacing, remember – trees need room to grow! Fertilizers are not necessary but can be beneficial to chestnuts. Follow the recommendations on your soil test report, or an acid-loving fertilizer high in nitrogen is generally beneficial (read labels carefully and follow directions closely!). Make sure to water chestnuts regularly for the first year. Once well-established, there isn’t much need to water unless there is a severe drought.
Planting American Chestnut Seedlings in Pots
Why plant an American chestnut seedling in a pot?
There are very few circumstances in which you would receive American chestnut seedlings and choose to plant them in pots. In general, the goal is to get seedlings in the ground as soon as possible. However, you may receive bareroot American chestnut seedlings from TACF’s Annual Wild-Type Seedling Sale and live in a northern region where the ground is still frozen. In that case, you might either “heel in” the plants so they don’t break dormancy until planted, or temporarily plant them in containers indoors and allow them to leaf out before planting in the ground.
Heeling In Bareroot Seedlings
This may be useful if you must wait more than a few days before planting bareroot seedlings. “Heeling in” refers to the temporary planting of seedlings until they are ready for permanent planting. The goal is to keep the roots from drying out and to maintain the dormancy of the plant. Bareroot seedlings can be heeled in a shallow v-shaped trench outdoors or, if that’s not possible, a five-gallon bucket, or wheelbarrow. Five-gallon bucket method: remove all packaging from seedlings, wet the roots, place the bundle in the bottom of the bucket, and cover the roots loosely with damp soil, mulch, or sand. Make sure the bucket has drainage holes. Ideally, they should be kept somewhere cool to maintain dormancy such as a garage, basement, or walk-in cooler.
Planting Bareroot Seedlings in Pots
The same general rules of planting seed in pots apply to planting seedlings in pots. Pots or containers should have holes in the bottom for good drainage. If you must keep seedlings in pots for longer than a year, the bigger the pot, the better. Chestnuts have deep tap roots so deeper pots are beneficial. Plant one seedling per pot. Soilless planting mixes provide good drainage but tend to include a lot of peat moss, which can be difficult to get wet. It is often easiest to wet the planting mix in a larger container so you can work the water in by mixing (think kneading dough). Remember that American chestnuts do not like to be too wet, so keep this in mind when choosing a planting mix. A simple mix of 1/3 each peat moss, perlite, and vermiculite is a great high-drainage mix that many chestnut growers use. This mix does not hold too much moisture, so if you forget to water your trees regularly you should look for a mix that holds a little more moisture, like Sun Gro Metro-Mix 560 Coir. When you are ready to plant your seedlings, see preparing seedlings (if your seedlings have leafed out indoors) and planting seedlings in the ground.
Preparing American Chestnut Seedlings to Plant in the Ground
Hardening Off
Leafed-out seedlings, especially those started indoors in containers, must acclimate to the outdoor environment before planting in the ground to prevent leaf scorch and dieback. This is called “hardening off” and will help make transplanting more successful. Ease new seedlings into full exposure to sun and wind by placing them on a covered porch, under a shade tree, or in a protected area outside. Remove any remnant nutshell from the base of the seedling to avoid attracting wildlife. Leafed-out seedlings will need to acclimate for a week or two, but bare-root seedlings do not, as they usually have no leaves at the time of planting.
If you receive bareroot seedlings from TACF’s Annual Wild-Type Seedling Sale, they do not require hardening off and are ready for immediate planting outside. If you can’t plant immediately, read about “heeling in” your seedlings above. If you choose to plant seedlings in a container indoors first, they will require hardening off before planting in the ground.
Planting American Chestnut Seedlings in the Ground
Preparing Seedlings
If you have leafed-out seedlings grown in containers indoors, read about hardening off above before planting. If you’re starting with bareroot seedlings, then you can immediately plant them in the ground.
When to Plant
Plant after the ground has thawed, and, for leafed-out seedlings, after risk of frost.
Removing potting soil from roots before planting.
Planting Seedlings
Dig a small hole the same depth as the pot or root system, and about twice as wide. If your seedling is coming out of a container, gently remove it from the pot and work the root ball with your hands to break it up, being careful to avoid damaging the roots. Do this next to the hole to create a pile of potting soil that can be mixed with the native soil when you refill the hole. (Some growers choose to backfill with only native soil.) Hold the seedling in the hole so that the root collar (where the root and stem join) is level with the ground surface. Fill the hole halfway with soilless planting mix, pack well around the roots, then fill the rest of the way and pack down again. Use your foot to tamp the soil down firmly around the seedling and remove any air voids around the roots. As with seeds (see Direct-Sowing Chestnuts Outside, above), adding forest soil may be beneficial to young trees. An acid-loving fertilizer may be added to the hole, or a top dressing of compost may be used for fertilization.
Protecting & Caring For American Chestnut Tree Plantings
Wildlife Protection
Chestnut nuts, shoots, and roots can all be attractive food sources for wildlife species, and tree protection is very important. Direct-seeded nuts are the most vulnerable and need to be protected from predation. Options include tree shelters (store-bought plastic tubes often with ventilation holes), homemade aluminum flashing tubes, or cylinders made of hardware cloth or wire fencing. (See photos below.) Most rodent species (including voles), as well as turkey, raccoon, deer, and even bears, may eat chestnut seeds or seedlings, and the height (or depth) of the shelter should correspond with the wildlife threats that are present. It is best to pick the shortest shelter appropriate for the site’s predation type and sink it 2-4” to provide a barrier to tunneling rodents. Solid shelters over 2 feet are not generally recommended, as the trees are protected from the wind and do not develop the structural wood needed to support themselves when the shelters are removed, and the branching pattern can become abnormal. Tall shelters may also result in kinks or abnormal growth in the trunks of growing trees if not removed at the proper time. A combination of a shorter shelter for rodent protection and a wire cage to keep larger animals away may also be used.
This 18” vented plastic shelter is sunk 2-4” into the soil to protect the base of the seedling.
Metal flashing, sunk 2-4″ into the soil, can be useful for protecting from tunneling rodents like voles.
A wire cage can provide good protection from wildlife. This one was constructed of welded wire garden fencing, zip ties, and a hardwood stake.
This American chestnut orchard in MA uses landscape fabric for weed control.
Vegetation Control
One of the top killers of chestnut seedlings is weeds! Remove competing vegetation from the planting area so that planted chestnuts have full access to available resources. A vegetation-free space about 3 feet in diameter is good for young trees. Regular weeding can be a good option, but may not be practical or effective depending on the site and number of trees planted. Landscape fabric, competition mats, or mulch work well for additional protection, though these types of weed barriers may harbor voles, which can be a risk. Herbicides can be used but should only be attempted by someone with experience using chemicals. ALWAYS follow the directions on the label!
Insect Pests
Many insect pests can be problematic for chestnuts, such as Japanese beetles, aphids, cicadas, chestnut weevils, chestnut gall wasps, and spongy moths, to name a few. Be sure to contact your local extension agent for any pest questions – your local Land-Grant University may have a plant disease and insect identification/diagnostics lab that can identify pests and recommend control and prevention methods. Commercial insecticides may be used, but as with herbicides, they should only be used by someone with experience applying chemicals, and always follow the directions on the label. Some chemical-free methods of insect removal and control include simply spraying the pests off with a hose, knocking insects off into a bucket of soapy water, or attracting or introducing beneficial insects that feed on the pest you are trying to control.
Spongy moth caterpillars can damage your chestnuts. Natural and chemical controls are options for this pest.
Happy Growing!
Chestnuts are not always an easy species to grow, but armed with education and a support network, you should be on the path to becoming a successful grower. One of the best ways to identify and understand the pathogens, pests, and other problems that may arise in your area is to talk to your local extension agent. Also, don’t hesitate to contact us! TACF’s regional science coordinators and farm staff have lots of experience growing, observing, and troubleshooting chestnut plantings.
Thank you so much for supporting the restoration of the American chestnut!
