White Oak Project
White Oak Project

Acorn Collection

Acorn Collection

Acorn Collection

How to Collect and Plant White Oak Acorns: 

  • Most acorns will be growing in the tops of the trees on the south side. Birds and squirrels eat nearly ripe acorns so a tree with lots of green acorns might not have many that actually fall to the ground for you to collect. 

  • White oak acorns drop from the tree starting in September in the northern part of the U.S. and early November in the southern U.S. If there is a late-summer drought, acorns could drop up to 2 weeks earlier than normal. 

  • Acorns that drop first from a particular tree are often immature, unfilled, diseased, or gall/insect infested. These acorns will not produce a seedling once planted. BE PATIENT. Move the acorns that drop first away from your collection tree. The wildlife are happy to eat these. Wait until the acorns are all dropping at once to collect because these are the good ones that will produce a seedling. 

  • Do not collect acorns that have "pin holes" on the outside of the acorn because they are infested with

    weevils.

  • Do not pull acorns off the tree like you would an apple. Acorns that are still attached to the tree are not mature and unlike fruit such as apples which can ripen once you pick them, acorns will not “ripen” to maturity once they leave the tree. Acorns pulled off a tree are immature and will produce few and poor quality seedlings. 

  • Do not collect acorns that have their caps still attached or have caps that do not slip off easily. Most of these acorns were blown off the tree by wind or were thrown down by birds and squirrels before they were mature and they won’t produce a seedling when planted. However, sometimes mature acorns will drop with their caps on. If you pick up an acorn with a cap and the cap falls off easily when you touch it, then that acorn is mature and can be planted. If you have to pull on the cap to get it to come off, do not collect that acorn because it is not mature. Leave those for the wildlife. 

  • Once you decide it is time to collect, the acorns need to be picked up as soon as possible after they have fallen because the root will start to grow within a few days. You can still collect and plant white oak acorns that have an emerging root as long as the root is short (less than ¼ inch) but be gentle handling these acorns and plant them immediately. 

  • If you are not ready to plant, put your acorn collection in a plastic bag and put it in a cool place such as the door in your refrigerator or a basement. You want the acorns to stay cool and moist but they also need oxygen so don’t close the bag up all the way and place some holes in the bag. Heat and drying out will kill the acorns. 

  • You can collect over time from the same tree by adding newly collected acorns to the bag in your refrigerator or basement. 

  • When you are done collecting acorns, fill a bucket with water and put the acorns in the bucket. The acorns that sink are more likely to germinate and produce seedlings. Throw away all the acorns that float because they will not produce a seedling due to weevils inside the acorn. Throw away acorns that float even if they have an emerging root because the weevil inside the acorn has eaten the baby stem so it will not grow.

  • Plant the acorns in moist soil with the pointy end facing down and cover the acorns with no more than ½” of soil. It is best to cover the planted acorns with a thin layer of dead leaves or other similar mulch to help hide them from animals, to keep the soil moist, and to insulate the acorns from cold temperatures. 

 

Root with weevil

Acorn with Weevil

This acorn grew a root but the weevil  inside has eaten the cells that would grow a stem so when planted no seedling would result.

Contact Information

Laura DeWald
Tree Improvement Specialist

T.P. Cooper Bldg Lexington, KY 40546-0073

859.562.2282

Laura.DeWald@uky.edu