Preparing Seedlings for Planting

Thawing Frozen Stock

Frozen seedlings are brittle and damage easily. Handle boxes carefully to avoid damage. Do not handle seedlings before they are thawed properly. Container seedlings may take 10 to 14 days to thaw properly. Allow enough lead time before the start of planting or the arrival of seedlings that were not frozen, whichever comes first. Careful monitoring is required, because the rate of thawing may vary by species and/or cooler location. When thawing trees:

• Handle seedlings very carefully. They are full of ice crystals and very brittle. Never attempt to separate frozen seedlings or bundles. Do not throw boxes of seedlings around.
  
  
• Let bundles thaw slowly at cool temperatures between 50 to 60 degrees Fahrenheit in an area protected from wind and direct sunlight. Thawing time will vary. Allow enough time for thawing.
  
  
• Never thaw seedlings in warm water.
  
  
• Once the seedlings have thawed, handle them as unfrozen stock. If seedlings are stored in a refrigerated cooler, reset the cooler’s temperature and maintain optimum temperatures.
  
  
• If the cooler must handle both frozen and thawed seedlings, frozen seedlings should be removed by taking individual boxes or groups of boxes from the cooler. Seedlings should be taken to a relatively cool storage area and allowed to thaw slowly. Inside storage areas, such as sheds or warehouses, where temperature ranges are generally 40 to 50 degrees Fahrenheit are ideal. If outside areas are used for storage, reflective blankets or tarps should protect the seedlings from low nighttime temperatures. Never allow tree boxes to be exposed to direct sunlight. Rapidly thawing seedlings is not advisable. If temperatures inside the tree box rise above 36 degrees Fahrenheit for more than a few hours, mold may develop rapidly. Keep the temperatures in the 32 to 34 degrees Fahrenheit range.

Preparing Bareroot Seedlings for Planting—Two basic systems are used for bareroot seedlings. One system is for early spring planting when freezing temperatures may be a problem and the other system is for late spring planting when warming temperatures are more likely to be the problem.