Each fall I see many requests on the internet for information about growing oaks from seed. I'm certainly no expert, and there are many ways other than mine that work well, but I thought I'd set up a page containing information on the method that has worked nicely for me for several years now. Give it a try this year and I think you'll have no trouble getting started with some nice little trees.

The trees shown below are Q. suber, cork oak.

Gathering quality acorns is probably the best way to guarantee a good start. I try to get them while they are still on the tree just as others are starting to fall. This makes it easier to get them before the worms do. If you can reach a branch and give it a little shake, the acorns that are ready will fall and you can easily collect them from the ground.

Unless you can't find others, discard any that have holes in them. This indicates that a grub has bored through the shell and is inside munching away on the seed. Some of these will still germinate, but it reduces your chances.

Collecting The Seed

Planting

The seed should be planted on the surface, about half-buried either on its side, or point-down. It's important to use a high quality coarse soil. I personally like to use a mix containing 50% pumice or lava, 25% compost and 25% commercial potting soil. This ensures good drainage and promotes good root development. For containers, I've found that large size styrofoam cups work perfectly. Their shape tends to make it very easy to remove the root mass when it's time to repot in the spring. Remember to poke a few holes in the bottom for drainage!

If you live in a mild climate plant the seeds in the fall after collecting, then just place them in the yard. Where winters are severe you can place the acorns and some compost in a plastic bag and store them in the fridge until spring. After planting, protect them from birds and animals with screen or chicken wire.

When the seedings are 4-6" tall it's time to root-prune and repot.

Note: This page is mainly geared towards growing oaks for bonsai. If you are growing them for the garden or field, DO NOT prune the roots. Skip the next section and go directly to "Repotting".

Most important here is stopping the growth of the tap root to promote good development and branching of the root system.

Root Pruning

Remove the plant from the cup and gently loosen the soil from the root ball so you can observe the roots to determine where to cut. The closer to the plant, the better. As long as there is a fair amount of development high on the tap root, don't be afraid to cut most of it off.

You can see in these images that I've removed almost all of the tap root, leaving just the very top where there is good side branching. Oaks are extremely tough trees and they can easily handle this stress if treated correctly.

Repotting

Use the same general soil mix that you germinated the seeds in. Again, the coarseness and drainage are very important for root development. A one gallon nursery pot is what I normally use, but I've put the plants directly into two and five gallon pots at times and there is quite a difference in growth over a season in those.

Plant the tree at a level so the remaining acorn is resting on top of the soil. It's very important to keep the plants out of direct sun for about two weeks to protect them until they recover from the "ordeal". After that, just put them out in the yard and treat them like any other potted plant. Don't fertilize for 3-4 weeks after repotting.

Here are a couple of trees shown in their first fall. They were pruned once in August to encourage branching. Even so, you can see that they have grown to good size just six months after potting.

On Their Way

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