Getting Started with Chestnuts
I have a lot of experience with chestnuts. I have grown chestnuts from seed, sold chestnut trees online and in person. But this past year my chestnuts sprouted in buckets failed over the winter. I learned a lot more as I have diversified my chestnut offerings in response to this loss, as well as expanded my knowledge through my in real life contacts. In this article I will share what I have learned so it will help you as well.
Varieties of Chestnuts
First, to set the stage, let’s review the main high-level types of chestnuts before diving into the varieties.
American chestnuts (Castanea dentata) are the very large chestnut trees that were (mostly) wiped out by the blight in the early 1900’s. Some pure American chestnuts exist but they are extremely susceptible to blight.
Chinese chestnuts (Castanea mollissima) and their varieties are widely available They are highly blight resistant. The trees do not grow as tall or wide as American chestnuts, and they are more rounded in shape. They tend to pollinate earlier and drop chestnuts earlier (in Kansas they drop nuts starting in early September, with most dropped by early October). The nuts are medium sized, and lighter brown in color. Some people think that the chestnuts are more starchy.
European chestnuts (Castanea sativa) are grown throughout Europe and the Mediterranean. They have flavorful nuts and are more marketable. European chestnut trees are susceptible to blight unless they are crossed with other types. It seems like most of them are crossed with Japanese varieties rather than Chinese or American varieties. These hybrids usually have French or Italian names. These hybrids are the main types of chestnuts in the North, especially in Michigan (according to Michigan State University).
Japanese chestnuts (Castanea crenata) are highly blight resistant and have large nuts. They are often crossed with European varieties.
I do not have much experience with European and Japanese hybrids but I have ordered some Japanese hybrids from Twisted Tree Farm to try out.
Chinese vs Hybrid Chestnuts
I have frequently had customers be turned off by Chinese chestnuts. Much of this is because of the view that Chinese chestnuts are inferior to the other chestnuts. They think that they want American chestnuts or hybrids. Much of this is a lack of telling the “story”.
Most Chinese chestnuts around here are hybrids anyway. Some are named varieties that are hybrids. I will deep dive into the varieties that I am growing shortly.
American/Chinese hybrid chestnuts
American and Chinese hybrids are Castanea dentata x Castanea mollissima. The trees get larger than Chinese chestnut trees. The nuts are darker and often larger. The American/Chinese hybrid chestnut trees drop their nuts later in the season, into mid-October in Kansas.
Why does everyone want Dunstan Chestnuts?
Many people call these American/Chinese chestnut hybrids “Dunstans”. But Dunstan (TM) chestnuts are a trademark of Chestnut Hill Nursery. They are the result of efforts over a generation ago of one lone surviving American chestnut seedling crossbred with Chinese chestnuts.
You frequently see chestnuts sold in the Spring and Fall on eBay listed as “Dunstans”. Technically they are not supposed to use that term.
You can get real Dunstans direct from Chestnut Hill Nursery or they ship to many stores (mostly Walmarts) East of the Mississippi. Here is the store locator for their shipments and when they expect them to arrive. They have a few stores in Missouri and one store they ship to in Oklahoma. The trees shipped to Walmart are usually big trees in 2 and 3 gallon pots. They are expensive – $45-65.
I bought 2 Dunstans a few years ago from the Walmart in St. Joseph, MO and planted them in the pasture with a T-post fence/cage around them. They have not thrived, mainly because the horses (and especially the donkey) push down the fence and eat the branches in the Winter. In addition, they are grown and shipped from Florida. They do not seem to do well in Kansas.
Local American/Chinese hybrids seem to do much better.
Chinese Chestnut Half Sibs
Half sibs are seedlings grown from seed from a known mother tree that is open pollinated by any of the surrounding trees.
Qing (pronounced “Ching”) and Resilient are examples of Chinese Chestnut Half Sibs.
New Chestnut varieties that I am growing this year
This year I am growing several new varieties of chestnuts. Half sibs: Qing, Resilient. Japanese/American hybrids.
I am also sprouting Chinese chestnuts, as usual, from my local trees. And I am sprouting American/Chinese hybrids from seed, including the HUGE Revival variety.
However, you have to be careful mixing American (and especially European) hybrids with large nuts. Those trees are usually pollen sterile, so they need a pollinator. Some varieties, like Colossal, may have Internal Nut Breakdown (internal nut rot) if pollinated by Chinese chestnuts.
Chestnuts – soil and pH needs
Chestnuts need moderately acidic soil, somewhere between 4.5 and 6.5 pH. By comparison, 7 pH is considered neutral and “base” and most garden vegetables require a pH between 6 and 7.
To get more acidic soil, add sulfur. For more alkaline soil, add garden lime.
Chestnuts need trace minerals like Boron, I have seen suggested that 1 tsp of borax, dissolved in water, poured on an 8×4 garden bed can help with this.
Fertilizing Chestnut Trees
Many sites, including Michigan State University, say that you should not put fertilizer in the hole when planting chestnut trees. You want the chestnut to grow out into the soil seeking nutrients.
If you do fertilize, add some 10-10-10 fertilizer lightly to the top of the soil.
Fertilizing is very important in Year 2 onward, and especially in Year 5 onward when it starts bearing nuts. Usually add fertilizer with nitrogen at 1 pound per 1″ diameter of the trunk. This seems like a lot. I am obviously not fertilizing at this level, but will kick it up a notch this year.
Foliar feeding (spraying the leaves, not adding to the soil) seems to be a good plan for fertilizing, especially during the year.
Do not fertilize past July or it may cause the tree to keep growing new growth and leaves into the Fall instead of being prepared for sleep/dormancy. Using a timed fertilizer like Osmocote could also be a problem if the timed release causes it to go past the point where it needs to be going dormant.
Also, if you give to much nitrogen to a nut bearing chestnut after July it may keep putting on new growth instead of creating nuts.
Sprouting chestnuts from seed
For sprouting chestnut seedlings from seed, I first put them in a bucket of sand over the winter (click to see my process). I transfer the chestnuts to tree pots as they start to sprout out nubs in the Spring. I put a layer of compost in the bottom of the pot, then regular soil above it and the chestnut (2 chestnuts per tree pot) into the soil.
These are the chestnuts grown out in the tree pots:
Good luck on your chestnut orchards!
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Chestnuts, hazelnuts, elderberry, and comfrey that are adapted to the Midwest.
GrowNutTrees.com
Raised beds that I am building to test Perennial Kitchen Garden layouts:
Vego Garden Modular Metal Raised Bed (which I will make 5′ x 3.5′, 17″ tall).
I use this for a perennial kitchen garden – growing herbs to use daily in the kitchen. Just come along and pick what you need for tonight’s dinner.
Meadow Creature Broadfork is my favorite tool for starting new garden beds. I turn over the sod, add a layer of compost, then Milpa, and cover with woodchips.
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