Soak your acorns indoors for around 48 hours. This helps trigger root development by changing their growing environment and activating their enzymes.
If your acorn has a cap on it, make sure to also remove this at this stage. If the cap doesn't come off, it's another indication that your acorn may not be mature.
After letting your acorns soak, it's time to prepare them for seed stratification. This is the process of tricking the acorns into thinking it is winter (their dormant season) by keeping them in cold conditions.
Wrap them in a small piece of damp paper towel, placed inside a sealed freezer bag. Place this in the vegetable crisper of your fridge. Make sure to check your acorn every few days to check the moisture level and observe if the acorn has sprouted a root. Take care not to let the paper towel become too wet, but don't let it dry out either - moisture is essential for germinating acorns, just as it is for seed germination. Acorns are sensitive to mold. Nothing to worry about, the forest floor is also covered in many mold spores. If your seeds develop mold, wipe them off gently with diluted hydrogen peroxide, and put them back in a new baggie with a new paper towel.
After a 4-6 week period of stratification, your acorns should have developed a small root. Taking it out of the freezer bag and placing it in a warmer temperature that tricks it into thinking its growing season has begun. The root that has emerged at the bottom of your acorn is a taproot.
To sprout your oak tree in water, the key is to keep the acorn dry and the roots submerged in water.
Elevate the acorn above the water, holding it in place. Using a glass jar allows you to observe root growth. This is where patience is required, as your acorn can stay in this set-up for up to a year long. In that time, don't make water propagation mistakes by ignoring it. You still need to provide care for your acorn while it develops roots.
Change out the water regularly to keep it clean and make sure to top it up so the roots don't dry out. You can also move your rooting acorn to a brighter windowsill than it's previous position (although, still out of direct sunlight) and noticed roots start to grow at a faster rate.
As your acorn roots, you will notice the acorn itself become smaller as the nutrients are being used up for root growth. After a robust root system has developed, and you have a shoot or two growing from your acorn, it's time to transplant your seedling, or oakling.
Once your acorn starts rooting, plant it in a container where it can grow for a while, since oaks develop a deep taproot that doesn't transplant well. Try to avoid moving it once it's more than a few inches tall - oak seedlings are delicate and prefer to settle in from the start.
Use a pot with drainage holes to allow excess water to flow away and prevents issues of root rot/
Make sure to climatize your oak tree to outdoor conditions to harden it off. Start by putting it outside during the day and bringing it indoors at night until temperatures are warmer. Transplant your tree 30’ away from houses, utility lines or structures. Planting oaks together is a good idea; up to 20’ apart.
You can then continue to provide optimal care for your young oak tree and watch it get bigger and bigger. With a bit of protection from critters like deer and rabbits, your oak should get through its first winter and be well on its way to becoming a sturdy young tree.