How to grow chestnuts
If you have the space, chestnuts are one of the best trees to grow; both for their edible nuts and useful timber, says Yotam Kay.
Permaculture farmer and market gardener Yotam Kay has tips.
When we moved to Pakaraka Farm in 2014, chestnuts became an integral part of our lives and culture. The 25-year-old chestnut orchard on the farm, with its 40 trees, produces an abundance of edible chestnuts. With many trees yielding over 50kg each, we have lots of this incredible food to eat and share, from mid-March to early June.
Chestnuts trees are highly valued for both their edible nuts and timber. The nuts are an incredible source of food, and they are so unique they deserve their own category. Although distinctly unique in flavour, most people I have met agree that they are most similar to kumara¯ in taste.
The fruit consists of about 50 per cent water and 45 per cent carbohydrates, with only a small percentage of oils and proteins. Chestnuts are also gluten-free and rich in fibre, minerals and vitamins. These unique properties make the chestnut trees a great source of perennial carbohydrates – meaning they can replace some of our reliance on monoculturally grown and imported grains, and increase our local food resilience.
The chestnut has two shells. The outer shell with its spiky burrs protects nuts while growing, and usually contains two to three nuts. If you are lucky to have a free-clinging variety, the nuts will fall out of the burr. If not, you will need to step on the burr (with sturdy footwear) and separate the burr from the nuts. The brown shell that remains protects the nut’s flesh and is not edible. There are several techniques for peeling this nut (detailed over the page).
Being such a fantastic food source, chestnuts are also attractive to many farm animals, including cattle, sheep and pigs. We feed our smaller grade nuts and the peels to our cattle and sheep, which love them. They usually follow us around the farm through the autumn and early winter, with the anticipation of this nourishing food. We find it a valuable supplement to their diet, especially at a time of year when grass growth is relatively slow.
The chestnut tree’s hardwood timber is extremely hard and has been extensively used for furnituremaking, firewood and fencing.
In Europe, the chestnut orchards were traditionally managed by coppicing on a 10- to 15-year cycle. Coppicing involves cutting the trunk low and letting the tree grow new branches from the base, which tends to be healthy and straight. In our permaculture studies, we visited such orchards, and though many are now abandoned, the trees are healthy, strong and prolific.
How to grow
Chestnuts are deciduous trees, related to oaks and beeches. The trees can grow up to 25m in height and can live for centuries, with some cultivated trees found to have lived for more than 1000 years.
Their growing habit makes them suitable for large gardens and farms, rather than small sections. Chestnut trees can be planted in the paddock, and used where cattle and sheep can enjoy their summer shade and munch on the nuts in the autumn. They are, on a similar note, a good tree for silvopasture systems.
These cold hardy trees will happily grow all across New Zealand – just be mindful that they need free-draining soils for good health. As the trees are wind-pollinated and require another tree for crosspollinating, you will need to grow at least two in close proximity to ensure a crop.
You can plant chestnuts grown from seed or grafted trees. The grafted trees will produce a few years earlier
than seedlings, and with a good variety, the grafted trees will produce large nuts that easily separate from the burrs and shell.
Most trees available will be European-Japanese hybrids, which have great flavour and are disease resistant, but with flesh that tends to cling to the shell.
Chestnuts trees are best planted in the winter, like all deciduous trees which use the precious winter days to grow their root system.
The trees greatly benefit from generous mulching of 20 to 30cm layer of woodchips, which encourages the fungal-dominated soil biological community that suits these hardwood trees.
Care and maintenance
Once established, the trees require little care. As the fruits are only harvested from the ground, the disease-free trees don’t need to be managed for easy picking, and no pruning is required, and the trees can be left to grow according to their liking.
As the fruits are forming on that outer canopy layer, the only situation in which you can consider pruning is if the canopy layer is getting crowded, and you want to maximise the fruit set from your trees.
The trees will need to be watered during the first summers, but as they mature, they won’t require extra watering (though we did find the trees that did best were closer to the drain, which gave them more access to water). If the planting site is exposed to strong winds, the trees will benefit from staking.
Think about how you will control the vegetation around the trees, as you will need to pick the nuts from the ground – much easier to do on mowed grass. To make the harvesting easier, we tend to rake the ground around the trees and clear any empty burrs to quickly identify the newly fallen fruits. We graze sheep under the trees most of the year, but a few months before the harvest, we remove them from the area and mow it closer to the harvest. Once we finish the harvest for the season, we let the sheep back in, so they can graze and eat any of the late nuts left on the ground.
Harvest
The nuts are ready to eat when they fall to the ground and are generally picked up by hand. If the nuts didn’t separate from the burrs upon falling from the tree, you will need to separate them, either by stepping on them (my preferred option) or by hand (wearing thick gloves). We have also started using a purpose-built nut harvester – an elliptical wire cage on a handle, which collects the nuts by rolling it.
Our orchard was planted with seedlings, and therefore each of our trees is a bit different. Each tree drops off nuts for about two to three weeks, with the early trees fruiting in mid-March and the late trees fruiting around the end of April.
The nuts vary in size, shape and colour, but they are all perfectly edible. The smaller nuts, 1 to 2cm wide, are not really worth peeling and we feed them to the farm animals. But the 3 to 5cm nuts can be processed in various ways.
With the nuts being low in fat, they are relatively perishable and need to be harvested fresh and kept in refrigeration, or frozen dried for a year-round supply.
Their peak eating qualities (when they are the sweetest), is about five days after they fall off the tree at room temperature, or two weeks if kept in the fridge.
Nuts kept in the fridge can keep for one to two months. If you are using stored nuts, it is best to floattest them and use the ones that sink. Floating nuts have air pockets which indicate they are less fresh and might be rotten. We make sure to cut any floating nuts, to check that the flesh is white-yellow in colour, and throw away or cut off any brown rotten parts.
We aim to collect the nuts off the ground every day or two. This also reduces the damage from possums and rats, which wait in anticipation for this delicious food.
Peeling chestnuts
Chestnuts need to be peeled and cooked prior to eating them.
There are several techniques to get into the rich flesh of the chestnut.
One technique is to separate the flesh from the peel after cooking. Bring the nuts to the boil, simmer for about 30 minutes, and let cool. Once they are still warm but cool enough to comfortably handle, cut them in half and scoop out the flesh. This is the base for dozens of recipes.
Once cooked and mashed, they can be mixed into any dough to improve its flavour and nutritional value, used for cakes, stuffing and made into the famous conserve, creme de marrons. We even throw them whole into soups and casseroles.
Another way to peel the chestnuts at home is with either a dedicated Japanese chestnut peeler or a regular kitchen knife. To peel them raw, cut the top and bottom of the nut, and then cut a line from the top to the bottom, which allows for easy removal of the shell. With this method, the nuts keep their shape, and they are perfect for roasting and frying, and suitable for use in various ways.
The inner peel, the pellicle, which is the thin skin around the flesh, is edible but has a rougher texture. We tend to leave it on, as it is where a lot of the nutrition is, but you can peel it off too if it bothers you.
If you want to roast chestnuts with their shell on (arguably one of the most familiar and popular ways to enjoy this treat), score them first – this prevents them from exploding in the oven! Just score two lines in the shell, in the shape of an X.