Growing a chestnut tree from a seed requires you follow a few steps in order for the seedling to develop correctly. Before you begin, make sure that you have enough space for two trees. You need to plant at least two trees in order to cross pollinate and produce nuts. You also need to decide if you are going to start your seeds indoors or outdoors.
Step 1 - Prepare Your Seeds
Chestnuts can be harvested from underneath mature chestnut trees after they fall in autumn, usually in late November. Choose nuts that look healthy and plump, without any signs of fungus or rot. Keep in mind that chestnut trees standing on their own will usually produce shriveled seeds that will not germinate because they have not been properly pollinated.
Chestnuts need to have at least three months of cold before they can germinate. A popular method of preparing them is refrigeration. Place your seeds in a plastic bag filled with moist peat moss. Poke holes in the bag with a toothpick to promote circulation and to help prevent the seeds from molding. They should be stored at 32 to 34 degrees Fahrenheit (towards the top of the refrigerator). If it gets any warmer than this the seeds may begin to sprout, which makes them harder to plant later on. Check back on the seeds frequently to ensure the peat moss is kept moist, but never allow the peat moss to become dry or soggy. Never freeze your chestnuts, either. The seeds can be pulled from the refrigeration towards the end of February or left in for two to three years. February is when you will want to start growing the seedlings inside.
Tip: You can also store your chestnuts in moist sawdust, unmilled sphagnum, sand, or vermiculite.
Step 2 - Choose Your Planting Method
Two different planting methods involve making newspaper cones stapled shut at the bottom, or using paper milk cartons with the bottom cut out. The cut-out bottom allows the roots to form with proper aeration. The cartons should be placed over a window screen or hardware cloth to keep the dirt from falling out of the bottom. Whatever method that you choose, planting the nut is the same. Use a peat moss, sand, and mulch mixture to develop a well-draining soil. Commercial potting mixes are typically too dense for chestnut germination, especially with over-watering. Place the chestnut on its side 1 to 1 1/2 inches into the mixture, and ensure that you have a stable place to set your containers.
Step 3 - Keep an Eye on Them
Once the chestnuts are planted, place them in a sunny area between 70 and 80 degrees Fahrenheit, and do not let them reach a temperature below 60 degrees. You can put them in a sunny window, a greenhouse, or under grow lights. You can also place a heating pad on low heat underneath the pot.
Keep the peat moss moist, but not wet or you will promote mildew and rot and the seedling will not sprout.
Step 4 - Move it Outside
It is time to move your seedling outside when the danger of the last frost has past and germination has begun, usually in mid-May. A trick for acclimating your seedling to outdoor weather is to place the container outside under the shade of a tree with newspaper or hay around the roots to keep them warm. Keep it here for a few days, slowly moving it into full sun. This process is called hardening off.
Step 5 - Dig Your Hole
Choose a spot for your chestnut that is in full sunlight and has well-drained soil. Avoid places with clay soil and high elevations. Remember, you need to plant at least two chestnut trees that should be planted at least 10 feet apart. Dig a hole two feet in depth by at least 1 1/2 feet in width. The reason you should dig a big hole for such a little seed is to promote drainage. Fill the hole halfway with a peat moss, sand, and perlite mixture. You can also use leaves that are not fully composted yet. Either cut the bottom off of the newspaper cone or slip the seedling out of the bottom of the milk carton. You do not want to disturb the chestnut more than needed. Fill the rest of the hole with the same mixture and pat down firmly.
Step 6 - Water and Protect
Water your tree about once a week, remembering to keep it only damp, not wet. If the soil seems to be growing compacted, add more peat moss to loosen it up and keep good drainage. After the first growing year, decrease watering to hot days and times of drought.
Tip: Fertilize occasionally using a complete liquid fertilizer or a fertilizer for acid-loving plants like rhododendrons or azaleas.
Animals love to eat new little seedlings and sometimes will dig for the nut before it has a chance to turn into a tree. Protect your investment by using a tree shelter. This will help to keep the deer and rodents away. You can also plant your seedling in a protected pot or garden bed to keep it protected from animal damage. When it is a year old and thus more mature and strong, you can transplant it again into its permanent spot.
Mulching your seedling is very important for inhibiting weed growth and keeping the soil moist. Avoid using wood chip mulch because it may attract rodents. Stone, plastic, rubber, pine needle, and leaf mulch are all great options. Your mulch layer should be two to three inches deep and be kept two to three inches away from the trunk of the sapling in the case of natural mulches.
To protect the delicate seedling from sun scald, keep a light layer of hay over the chestnut's new leaves for the first two weeks outside. Then, gradually remove.
Tip: The first month after planting, gently remove the chestnut seed from the seedling. Rodents and other animals are much more likely to attack the seedling to get to the plump chestnut.
With a little patience and a lot of attention you can brag that you grew you own a chestnut tree from just a small seed.