Bare root trees are woody plants, such as fruit trees, roses, and shrubs, typically purchased during their dormant season in late winter or early spring. These plants are harvested from the ground with no soil surrounding their root systems, which allows for easier, lighter, and more economical shipping. Because the roots are exposed to air, they lose moisture quickly. Therefore, the rehydration process, or soaking, is a necessary first step to ensure a successful transplant and prepare the tree for the stress of being moved into its new permanent location.
Why Soaking Bare Roots Is Necessary
Soaking bare roots provides relief from the desiccation that occurs during the harvesting, storage, and shipping process. The fine root hairs, which are responsible for water and nutrient absorption, are highly susceptible to drying out when exposed to air. Even if the roots appear moist upon arrival, they have typically lost a significant amount of stored water.
This water loss triggers a physiological shock that can inhibit the plant’s ability to establish itself. By soaking the roots, the plant cells are fully rehydrated through osmosis, restoring turgor pressure within the tissues. A fully hydrated tree can better withstand post-planting stress and begin the process of root growth and nutrient uptake much sooner than a dry one.
Preparing the Roots Before Soaking
The soaking process begins with a thorough inspection and preparation of the root system. First, carefully remove all packaging materials, such as plastic wraps, sawdust, or shredded paper, ensuring no remnants remain tightly bound around the crown or roots. This allows for a clear view of the root structure and prevents material from wicking moisture away from the plant.
Next, inspect the roots for any damage that occurred during transit or harvesting. Use sharp, sterile shears to trim off any broken, frayed, or dead roots, making clean, angled cuts back to healthy, white tissue. Healthy roots should be pliable, but damaged ones often appear dark, shriveled, or brittle. The water used for soaking should be cool or tepid, and the container must be large enough to completely submerge the entire root mass without bending the roots.
Determining the Optimal Soaking Duration
The ideal soaking time balances replenishing lost moisture and preventing root suffocation, with a recommended range of 2 to 12 hours for most species. For common bare root stock, such as fruit trees and roses, a soaking period of 3 to 6 hours is sufficient to achieve full rehydration. Soaking for less than one hour is inadequate, as the tissues will not have enough time to absorb the necessary volume of water.
The condition of the roots upon arrival influences the duration. Extremely dry or shriveled roots may benefit from a longer soak, potentially up to 24 hours. If the roots arrive looking plump and well-hydrated, the soaking time can be kept closer to the lower end of the range. Twenty-four hours should be considered the absolute maximum limit before potential damage begins to occur.
Addressing Risks of Soaking Too Long
Exceeding the recommended 24-hour soaking period introduces the risk of root suffocation, scientifically known as anoxia. Plant roots are living organs that require oxygen for cellular respiration, which fuels growth and nutrient uptake. When submerged in standing water for too long, the roots rapidly deplete the dissolved oxygen.
Once the oxygen is exhausted, the roots begin to die, leading to root rot and compromising the plant’s long-term viability. Roots that have been waterlogged for an extended period often develop a slimy texture and may emit a foul, sour odor when removed from the water. This damage is irreversible and diminishes the tree’s ability to survive after planting.
Immediate Steps After Soaking
Once the soaking time is completed, the bare root tree must be planted into the soil immediately. The goal is to move the roots from the water environment into the soil as quickly as possible to ensure continued establishment. Do not allow the roots to air-dry between removal from the water and planting.
If an unavoidable delay occurs, the roots must be temporarily protected from drying out. The best temporary measure is to “heel in” the tree by burying the roots in a shallow trench filled with moist soil, sand, or sawdust in a cool, shaded location. Alternatively, the roots can be wrapped in damp burlap or a thick layer of moist newspaper, but this temporary storage should not extend beyond one to two days.