Acorn collecting: we need your help collecting acorns from throughout the range of white oak. Collecting is finished for 2019 but we will be collecting during the fall of 2020 and 2021. Folks should contact Laura DeWald (Laura.DeWald@uky.edu) if they are interested in helping with the white oak acorn collection effort and she will send you a collecting kit that includes full instructions and a postage-paid box to use to return the acorns to the University of Kentucky.

   

A critical first step in the white oak genetics project is collecting acorns from as many trees as possible from all eastern US states, and from all the different environmental regions within each state. This will ensure we have a broad sample of white oak genetic diversity from across the natural range the species occurs. White oak acorns mature at different times in different places and thus the collection can only happen with the help of many individuals and organizations. If you see a beautiful white oak tree we would love to have acorns from it!!!

 

A collection kit is sent to anyone willing to help collect white oak acorns along with instructions and a postage-paid box for getting the acorns back to the University of Kentucky. All trees acorns are collected from are documented in TreeSnap which is an app you can download for free onto your phone or I-pad. Please spread the word about collecting acorns to ensure we have the best representation of the white oak resource!

   

   

Immature white oak acorns in late July

Immature white oak acorns in late July.

   

Nearly mature acorns in mid-Sept

Nearly mature acorns in mid-Sept.

   

Mature white oak acorns

Mature white oak acorns.

   

Mature acorn with root emerging

Mature acorn with root emerging.

Collecting and Planting 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 mid-Sept. in the northern part of the US and late Oct. or early Nov. in the southern US. 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 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 insects.
  • 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 not produce 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 very short (less than ¼ inch) but be super gentle handling these acorns and plant them immediately. The emerging root shown in photo #4 is a little long and susceptible to being broken. If that happens the acorn will die.
  • If you are not ready to plant, put your acorn collection in a plastic zip-lock type storage 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. 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 gently 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. You don’t need to do this step with acorns that have roots emerging because they are already germinating and can produce a seedling.
  • 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.

   

Acorn weevil

A hole indicates an acorn has a weevil in it.

Here you can see a larvae.

   

Adult acorn weevil.