Advantages of container-grown seedlings (with an air-pruned root system) over barefoot seedlings:
- The plant’s roots are surrounded by a peat-based substrate which contains a small amount of nutrients and moisture;
- It can be planted throughout the vegetation period, including summer;
- Higher survival rate;
- Small root damage risk;
- Transplant shock is minimal or non-existent;
- Planting performance is 3-4 times higher;
- Planting does not require professional skills;
- Seedlings are less damaged by transporting.
High-quality seedlings with an air-pruned root system:
- have green needles;
- have a well-developed top and intact terminal bud;
- do not show signs of mechanical damage;
- come with a moist peat ball;
- come as a single seedling per peat ball;
- and do not have twisted roots.
Before planting seedlings with an air-pruned root system:
- remove the roots growing out of the cultivation tray or peat ball with scissors or a sharp knife;
- be very careful, because young seedlings break easily.
When buying forest seedlings, choose those which have been cultivated in trays enabling air-pruning (for example, in Plantek F trays). Cultivation trays enabling air-pruning ensure the higher quality and survival rate of forest seedlings.
Thaw before planting
A frozen plant will dry out because it cannot absorb water from an icy soil ball.
Keep in a cool place
In a cellar or any other cool place (8-14°C).
Thawing seedlings too quickly – for example, placing them directly from the freezer into a room with an air temperature of 20°C – may cause damage to their root system.
Keep in the shade
Direct sunlight is not good for frozen seedlings.
First, let the seedlings thaw in an almost dark place for 2-3 days, then let them get used to light in a place with ample shade. After that, water and plant them.
During thawing, cover the seedlings with special-purpose garden fabric if desired.
Remove the covers from the seedling boxes and make holes in the sides of the boxes. Remove the seedlings in their plastic bags from the boxes or fold the tops of the bags down as low as possible. During thawing, the respiration rate of seedlings speeds up, quickly raising the temperature in stuffy plastic packages.
When calculating the planting time, reserve 3-5 days for thawing; in a cool place the thawing of packaged soil balls may take as long as one week.
During thawing, do not keep the seedlings in a completely dark place for more than a week, because thawed seedlings need sunlight.
Seedlings remain in a state of hibernation only at very low temperatures (< + 2°C ). Thawed seedlings should be planted as quickly as possible. If planting is delayed, cold-stored seedlings should be cared for exactly as seedlings stored outside i.e. dig them into the soil and make sure their roots are covered with moist soil.
Regularly check whether the peat balls are moist enough. Seedlings need watering if no water oozes from the peat when squeezed. Drying out of the peat ball is very dangerous to seedlings. Before planting, keep the seedlings immersed in water for at least a couple of hours or water them abundantly.