Preparing Nursery Plants for Winter

Protection Techniques

Field nurseries

1. Barriers and windbreaks can minimize wind burn.

2. Plants that are dug and overwintered need to be placed in the shade with heavy mulching around rootballs to prevent freezing.

Seedbeds and liner nurseries

1. Small plants have a reduced root system; where it is cold enough for frost heave, they can be heaved out of the ground and desiccate.

2. Heavy mulching is a solution. Use 6-8” after plants are dormant.

3. Clay or organic soils are more prone to frost heave.

4. Covering plants with polyester or polypropylene fabric provides protection, but heat builds up under fabric and may cause plants to break dormancy early.

Container nurseries

1. Major problems are desiccation and lack of root hardiness.

2. Rootballs may freeze, making water unavailable to evergreen tops.

3. Water adequately in winter to prevent desiccation; in addition, well-watered pots will have the thermal capacity to resist freezing during cold periods.

4. Avoid laying plants on side for long periods of time during winter. They will begin asymmetrical growth and bark may be subject to sunscalding.

5. Protection: cluster containers, mulch over top, and surround by hay bales. Shade protects against water loss and frost burn.

6. Protection: push containers tightly together and wrap the blocks with paper or plastic to prevent air movement.

7. Protection: structureless methods involve the use of thermal blankets and fabric completely covering the tops and sides of blocks of containers, stopping any air flow.

8. Hoop houses may be used to overwinter plants. Hardening allowed first, then cover pulled over hoops. North-south houses will be cooler than east-west ones. Ventilate, heat, insulate with double walls.

9. Containers may need herbicide treatment before going into winter storage; some greenhouse weeds can overwhelm a crop that has been buttoned up for winter.

Overwintering an Irrigation System

End-of-season checklist:

Entire system

1. Chlorinate to clean out systems.

Backflush sand filters

Inject liquid bleach (5.25% chlorine) at concentration of 500 ppm.

Allow for minimum of 30 minute contact time for farthest emitter.

Shut system down for 24 hours, then flush in following order:

-filters

-mainline and submain

-lateral lines

2. Filtration equipment

Flush and drain filters

Inspect filters for wear, corrosion, damage.

Check condition of seals, gaskets, and valve seats.

3. Valves

Completely drain all valves.

Clean corrosion, dirt, etc. from valves.

Lubricate valves.

Make sure all valves are open.

4. Controllers and sensors

Clean controllers and sensors.

Check condition of controller panel seals.

Remove and store batteries.

Flush and drain hydraulic control conduits.

Disconnect field wires.

Check for frayed, worn or broken electrical wires.

5. Chemical injection equipment

Thoroughly flush and drain.

Clean interior and exterior equipment surfaces.

Lubricate pumps, motors and gear reducers

Examine condition of check-valves and backflow preventers.

Cover shaft and other exposed metal with protective lubricant.

Check gaskets and seals.

6. Electric motors

Clean, lubricate, cover

7. Centrifugal pumps

Drain, clean, lubricate, cover