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. Eliminates blow over. 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 Insert Pot Spin Out treated Socket Pot 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.

Solving Root Escape Use 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 Spin Out treated fabric liner Insert Pot Socket Pot Use Spin Out-treated fabric bags such as Tex-R Agroliners inside the insert pot.

Disadvantages of PIP Insert 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 bark 1 part peat moss No sand.

Irrigation Pond or well. Filtered. Drip irrigation using: Micro-sprinklers Spray 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.

1 inch black poly lateral irrigation line Irrigation Schematic Spaghetti tube Spray stake or micro-sprinkler Insert pot Socket pot 1 inch black poly lateral irrigation line

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