It all depends….

HORTICULTURAL SOILS

Kevin Donnelly, CH

Supervisor of Quality Control

Midwest Trading Horticultural Supplies Inc.

MIDWEST TRADING

Its all about Logistics

Its all about Logistics

CENTER FOR HORTICULTURAL SOILS TESTING

AND RESEARCH (CHSTR)

Our capacity

pH/EC

Moisture Content

Bulk Density

Porosity

Weed Seed Bioassay

Top Soil Hydrometer

Solvita Compost Analysis

And much more…

QC Testing

Mixes

Raw components

Data Management and Tracking

Technical service

R&D

TOTAL QUALITY CONFIDENCE

Know everything we can about the products we

produce and components we use

Manage the natural variability in the material

Ask the right questions

to give the answers

value and meaning

HORTICULTURAL SOILS

“Any substrate used in the growth of

horticultural crops or used in horticultural

applications”

General Categories

Container Substrates

Engineered soils

Landscape Soils

Other

tissue culture; floral foam; hydroponic media

ENGINEERED SOILS

A soil or soilless substrate subject to testing and conformance to a specification

Prescribed spec A+B+C= ?

Straight forward, but will it work

Performance spec ?+?+?=A

Asks the right questions,

Both A+B+C=Z

Very challenging when A+B+C=D not Z

GREEN ROOF MEDIA

Storm Water Management***

Heat Island Effect

Air Quality

Energy Efficiency

Longer Roofing Membrane Life

Biodiversity

CHICAGO BOTANICAL GARDEN EXTENSIVE GREEN ROOF

MILLENNIUM PARK INTENSIVE GREEN ROOF

CHICAGO CITY HALL INTENSIVE & EXTENSIVE GREEN ROOF

GREEN ROOF COMPONENTS

STURCTURAL SOILS

STURCTURAL SOILS

RAIN GARDEN, BIOSWALES & LANDSCAPE

CDOT

Rain Garden

Bioswales

Other

RAIN GARDEN

BIOSWALE

BIOSWALE

OTHER

Golf Courses

Athletic Fields

LANDSCAPE/ PRODUCTION SOILS

Manufactured or amended parent soil

Garden/Landscape soil

Field production of horticultural crops

Soil Amendments

LANDSCAPE/PRODUCTION SOILS

Where do

Soils

Come

From?

LANDSCAPE/PRODUCTION SOILS

Large scale

development

that clears land

and sells off soil

Not a lot of

options in this

economy

CONTAINER SUBSTRATES

Substrates used in containers for the

production of horticultural crops

Some Key elements

Container size

Crop length

Limited soil volume

GREEN HOUSE AND PROPAGATION MEDIA

NURSERY AND TREE MEDIA

POTTING SOILS

GROWING MEDIA

Air

Water

Structure

Nutrient Reservoir

THE IDEAL MIX

It all depends….

Fits your growing style

Produces quality plants with limited

management

Consistent/Predictable

Cost effective

PHYSICAL PROPERTIES

Prevention is the only course of action

Only you can

prevent bad

porosity!

MACRO VS. MICROPORES

25% Solids

75% Water

25% Solids

45% Water

30% Air

CAPILLARY ACTION IN MIX

Important when sub irrigating containers

Pores act as a straw and

ZONE OF SATURATION

Amount mix will hold at the bottom

3% 10% 40%

CONTAINER SIZE

Size and Shape of container can effect water

air water relationships

Look at the force of gravity 45% Air

25% Air

10% Air

BULK DENSITY/ COMPACTION

Depending on how it is filled and handled can

impact air water relationships

Compact vs. lightly filed

Structure is not made in the bag

NESTING EFFECT

Air Porosity

20

5

20

20

SHRINK

Settling after watering

Component breakdown

Out the bottom?

Shrink from blending

Fill pots at optimum moisture content

WETTING AGENT

Aids in wetting

up mix

Peat is

hydrophobic

• Helps with even watering,

Not channeling down the sides of the pot

A good idea for postharvest quality

CHEMICAL PROPERTIES

PH

Will effect nutrient availability

Fluctuates over the course of the crop

The plant causes pH changes

Alkalinity of your water is important

May need to acid injection

Buffer capacity of your components

Lime and Iron Sulfate

PH

EC

AKA soluble salts

Measure of salt content in solution

Can be from good salts or bad

Many use EC as indication of fertility

Listed in dS/m or ppm (dS/m X 670)

Dilution method matters!!

OTHER MEASURMENTS

Organic Matter

CEC

C:N

Weed Seed presence

Wettability

Moisture content

TESTING

What do you test for

How Often

How do you test

Internal testing

External lab

What do you do with that

information

SAMPLING

How you sample may add bias to the test

Area of pot

Top 1/3rd

Middle 1/3rd

Bottom 1/3rd

Random sample or targeted sample

RANDOM

TARGETED

TESTING FOR PHYSICAL PROPERTIES

Air Porosity

Field Method

NCSU Porometer

Sieve analysis

Bulk Density

Shrink testing for

optimum moisture

Field Capacity = Flooded container

Container Capacity = Free water drained

TESTING FOR PHYSICAL PROPERTIES

Porosity

When Dividing by the Container Volume

Air Porosity

Dry Weight

Water Holding

Capacity

TESTING CHEMICAL

In house

EC

pH

External Lab

Nutrients

CEC

Etc.

EC

Method maters

1:1

2:1

SME

Pour Thru

Many use it for managing fert

If EC reading falls below X, then fertigate

PH TESTING

Moving Target

Can be adjusted

4

4.5

5

5.5

6

6.5

7

1 2 3 4 5 6 7 8 9

BIG POINT FOR ANY TESTING

Don’t make major changes right after testing

starts to correct issues that may be normal

Need historical values to see what is your norm

Plants don’t read test reports

Think about what the right question is

COMPONENTS

Its all about logistics

NUTRIENTS

Minerals/non coated

dolomite lime

Iron Sulfate

Controlled Release Fertilizers (CRF or SRF)

Encapsulated NPK+

NUTRIENTS

Organic Fertilizers

Kelp Meal

Bone Meal

Worm Castings

Bat Guano

Poultry Litter

AGGREGATES

Perlite

Vermiculite

Sand

Calcined clay

Oildri

LWA

Others

Lava

Glass

Polystyrene

Rockwool

ORGANIC COMPONENTS

Peat

Sphagnum

Reed Sedge

Pine

Rice

Coir

“Composts”

Landscape compost

Manure compost

Biosolids

Worm Casting

Mushroom “Compost”

Spent Mushroom Substrate

NEW PRODUCTS

Why we need them

Price

Availability

Quality

Sustainability

These are not

replacements

Look for local

Cheap

Effective

NEW FRONTIERS

Whole Tree Substrate

Corn Cobs

Miscanthus

Biochar

“Fingerprinted” media

BIOLOGICAL

Mycorrhizae

Benificial bacteria/fungi

These can be incorporated into mix

As well as some pesticides

PEAT MOSS

The Stuff Dreams Are Made Of

WHAT IS PEAT?

•Specifically we are referring

to sphagnum peat derived

from sphagnum moss

•Stable partially

decomposed organic matter

•Degradation slow due to

acidic anaerobic conditions

Like I said, the conditions in a bog inhibit decomposition.

Where some of our peat comes from

This is a smaller bog for Lambert compared to

The Virgil Nursery and the Ottawa facility!!

WHAT HAPPENS AT A BOG

Go from this: To:

SO IS IT SUSTAINABLE??

Clear cut bog

Pull off what may take

generations to grow

Disturb environment

42thousand acres of

280million harvested

Less than 0.02%

Peat biomass generates 60

times faster than harvested

Must restore bogs to

functioning wetland

On bog for 60-80 yrs

NO PEAT IS THE SAME

Differs from:

Bog to bog

Year to year

Company to company

Many different grades of

peat

Retail peat

How to manage that

variability

Blend everything to get

one base product

Have many different

products

NATURAL PRODUCTS WILL VARY

We have to individually tailor quality management

strategies to each product

Products change both Chemically and Physically

while we have them

You can’t tell just by looking at it, it must be tested

Come on the tour to learn more…

QUESTIONS?

THANK YOU

Yourhorticulturist.blogspot.com

We are always looking for a few good question

askers.