Pot in Pot Nursery Production

Commercial Plant Production

A Pot in Pot Nursery

What is pot in pot (PIP) production?

A method of producing of shade trees, intermediates, and shrubs using a combination of field growing and container production techniques.

PIP acres in production has been increasing steadily since the 1990’s.

More plants are grown per acre using PIP than field production (Physical and Economic Requirements for Pot-in-pot Nursery Production; McNiel, et al).

How does PIP production work?

Two different pots are used:Socket pot: set into the ground so that 3-6

inches of the container lip is above grade.Insert pot: this pot contains the growing

medium and plant. The insert pot “plugs” into the socket pot.

PIP schematic diagram

Advantages of PIP

Insulates the roots from temperature fluctuations.In traditional, above ground, container

production it is a well documented fact that high media temperatures kill roots. Media temperatures can exceed 140º F. in the sun.

Advantages of PIP

Allows for in-place overwintering.In traditional container production plants are

typically consolidated into quonset houses that are covered with white poly.

Decreases production time from liner to finished product.Water and fertilizer inputs are controlled by the

grower.

Advantages of PIP

Reduced water usage.Most PIP nurseries are drip irrigated.

Eliminates blow over.Traditional container grown plants with large

canopies tend to blow over.Blow over results in a loss of media and top-

dressed fertilizers.

Advantages of PIP

Year-round harvesting.Reduced harvesting labor compared to

field production.Field grown plants are generally harvested

when they are dormant.Digging plants out of the field is labor intensive.

Advantages of PIP

Prevents root loss associated with field harvesting.

Reduced shipping costs compared to field grown B&B plants.

Disadvantages of PIP

Higher initial cost of installation.Up front expenses include grading, tiling,

purchasing socket and insert pots, irrigation system installation, and liners.

Drainage concerns.PIP is recommended on sandy soils. It can be

accomplished on heavier soils providing they are properly drained.

Without proper drainage, the socket pots may fill up with water.

Disadvantages of PIP

Root escape into the socket pot and surrounding soil.Roots may grow through the drainage holes of

both the insert and socket pots.

Solving Root Escape

Apply a copper compound (Spin Out) to the bottom one-third or one-half of the socket pot.

The copper compound will kill the root tips when they reach it.

Insert Pot

Spin Out treated Socket Pot

Solving Root EscapeUse BioBarrier. BioBarrier is a cloth-like

material impregnated with Treflan herbicide.

A piece is cut to fit inside the bottom of the socket pot

The Biobarrier releases a gas that will prune the roots of the plant before they can grow out the drainage holes of the insert pot.

Requires a good seal between pots.

Insert Pot

Socket Pot

BioBarrier

Solving Root Escape

Use Spin Out-treated fabric bags such as Tex-R Agroliners inside the insert pot.

Spin Out treated fabric liner

Insert Pot

Socket Pot

Disadvantages of PIPInsert and socket pots

may stick together making removal difficult.

The bottom of the insert pot may sag, creating an uneven base.

The plants may be exposed to the drying effects of winter’s winds.

Limited flexibility in spacing plants.

Insert Pot

Socket Pot

Growing Media

Pine bark is the main component with particles in the 3/8 – 1/2 inch size.

A common media consists of:4 parts pine bark1 part peat mossNo sand.

Irrigation

Pond or well.Filtered.Drip irrigation using:

Micro-sprinklersSpray stakes

Coverage is important. The entire medium surface must be wetted. This is especially true if you top-dress fertilizers.

Larger pots may require 2 or more nozzles.

Irrigation Schematic

1 inch black poly lateral irrigation

line

Spaghetti tube Spray stake or

micro-sprinkler

Insert pot

Socket pot

Micro-sprinklers

Spray Stakes

The Nursery “Floor”

Bare soil.Grass buffer strips.Ground cover fabric.

Bare Soil “Floor”

Grass Buffer Strips

Ground Cover Fabric “Floor”

The End