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Chestnut nut grafting experiment

February 22, 2020 tarzan Comments 9 comments

Nut grafting

Beside regular grafting of scion to an established rootstock, there’s also a set of grafting techniques of germinating chestnut nuts like epicotyle grafting, inverted radicle grafting or grafting the nut directly. In this experiment, I’ve tried grafting chestnuts and red oak’s acorns. Chestnuts and oaks are related and some are claiming they can be successfully grafted together. Roots of an oak are much less prone to diseases and grow better, which makes such combination worth trying.

Seems so easy…

Small bud poking out of the sphagnum cover.

To successfully graft the nut, they first need to start germinating. Chestnuts start sprouting when their dormancy is broken after a period of cold stratification. When the sprout appear, all you need is to cut off the tip of the nut from which the sprout is growing and insert a small graft into the exposed round sprout inside the nut. It can be a bit delicate, but not too hard.

Preventing infections

To avoid contamination with molds or rot, best thing to use is sterilized moist peat moss or sphagnum moss. I used peat in the bottom of the containers and living sphagnum (which I grow myself) on top. Live sphagnum keeps the moisture well, has anti-fungal and anti-bacterial properties. It’s not a bad idea to disinfect the tools and nuts too in the process.

Waiting for results

I covered all the grafted nuts to preserve the moisture and expected them to take quite some time before I notice anything. Well, it didn’t take long, before they started callusing in just a day or two. In just a week or so, first roots appeared from the callus.
I did not expect the process to be that fast. It’s way faster than regular grafting, the only down-side I can think of is the fact that you get a plant that is only slightly better established than a seedling. Like with other grafting techniques, you can make a flowering plant if the scion holds the flower buds. That way, you can get pollen or female catkins to produce hybrids much faster and since the flowering plants are still small, they can easily be transported around.

Grafting chestnut to acorns

Red oak acorns have very hard shell, which makes it almost impossible to cut the tip off the way it can be done with chestnuts. I removed the shell and tried the same process, but I’ve learned that nuts didn’t hold the scion in place long enough and the growing sprout just pushed it out. Acorn grafting I tried needs some tweaking and I’m in a process of acquiring new acorns and experiment further.

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Germinating walnut tree

June 26, 2016 tarzan Comments 2 comments

I received several extremely large walnuts and decided to try making them germinate.

Walnuts are easy to propagate from seeds, but they grow slow at first and you don’t really know the size of the walnuts until the tree is already quite large. They also secrete juglone, a phytotoxic chemical that is toxic to many plants. All parts of the walnut tree have some level of juglone, which inhibits growth of plants around it. Juglone is also the reason, why it’s usually not a good idea to add any part of the plant into compost bin. My experience is, that when properly composted, juglone decomposes enough and doesn’t even bother tomato seedlings, which are otherwise extremely sensitive to juglone. Trees grow tall, with dense and broad crown. They can grow in most soils and can handle some drought.

To germinate the walnut, it have to be stratified for 3 to 4 month in a plastic bag with damp paper towel, moist peat or sand in a refrigerator. During the stratification, paper towel and the nuts can become mouldy. They can be washed in cold water and wrapped into new moist paper towel, before placing it into the fridge for some more time. I did not see any issues regarding the mold, all the walnuts I tried germinated into healthy seedlings, even if kept moldy for a while, before I’ve noticed and cleaned them.

After 4 months or when you feel the seeds are stratified enough to germinate, wash them in cold water and plant the nuts into well draining moist compost rich soil, 2 to 5 cm deep. They start sprouting in a couple of weeks and in a month or so, you can have your first little trees emerging. If it takes longer, seeds might not have been stratified enough and will take a bit longer to sprout. When they grow enough to handle, place them separately into large enough pots, buckets or directly into the ground. Walnuts are supposed to get larger if they get up-potted a couple of times when they are young. I have heard that story many times, but I have no idea if it is true.

When planting walnut trees outside, you have to make sure they have enough space to grow properly. If they grow close together, the overall appearance of the tree will be tall, without the broad crown. When they have enough space if you plant them 15-20 meters apart, they will grow more sturdy, thick and branched out trunk with broad and extremely dense canopy. It can get too dark under the trees for most plants to thrive, especially considering that the roots of walnut tree release juglone through the roots and keeps the competition away.

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