Presented at:

ACORN 2013

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Greenhouse mixes◦ Important variables◦ Mix components

Greenhouse trials◦ Observations◦ Lessons learned

Compost◦ Important variables◦ Production methods◦ Materials used◦ How to evaluate a good compost

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Aaron Randall, Owner, Sweet Valley Herbs

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Tim & Kirsten Livingstone, Owners, Strawberry Hill Farm

with Pat Toner, DAAF

Germinating mix ◦ Starter mix, Plug mix

Transplanting mix◦ Growing mix, Grow On mix

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Important Factors pH: 5.5 to 5.8

EC: <1.0 mmhos/cm

Must be low to prevent damage to young seedlings

StructureGood porosity, excellent drainage

Fine particle sized material

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Typical materials◦ Peat

◦ Perlite

◦ Vermiculite

Other possible materials◦ Worm Castings: <3%

◦ Compost: <5% -> Must have low EC

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Important FactorspH: 5.5 to 6.5

EC: Recommended ranges

NB Soil Lab .75 – 3.0

U of Mass 1.5 – 3.0

MOFGA 1.0 – 2.0

NBDAAF trials 1.9 – 3.9

StructureCourser material

Porosity & moisture holding capacity balanced

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Typical materials used◦ Sphagnum peat, AND/ OR

◦ Coir (the coconut husk)◦ Perlite◦ Vermiculite

Other common materials◦ Compost◦ Peat Humus (black peat, muck peat)◦ Aged bark◦ Worm Casting

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CautionCertified Organic Growers: Make sure no

commercial wetting agent added

Pro’s Excellent drainage

Good moisture holding capacity (MHC)

Plentiful in NB

Con’s Considered by some to

be a Non-renewable resource

Low pH – needs lime Low EC – needs fertilizer Hard to wet

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CautionMake sure Coir has low salt (EC) content

Pro’s Renewable resource

Peat substitute

Good MHC

pH is higher than peat

Less lime needed

Easier to re-wet

Con’s Carbon foot print Costs

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Pro’s Helps increase porosity

Good drainage capacity

Con’s Does not provide any

nutrients

Cannot hold nutrients

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CautionKnow your source

Some US sources contain 2-3% asbestos

Pro’s Provides good porosity

Good MHC

Holds nutrients

Good source of Calcium & Magnesium

Con’s Costs Easy to crumble

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Caution1. Watch % used

2. Keep EC in range

Pro’s Renewable resource

Can replace some peat

Reduces lime

Source of nutrients

Holds nutrients

Good MHC

Disease suppression qualities

Con’s Can rob nutrients from

plant if C:N is high Attracts fungus gnats

& shore flies if wood based

Reduces porosity

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Caution 1. Keep to <10% of mix2. Don’t confuse with compost – different product

Pro’s Renewable resource

Replaces some peat

Con’s Difficult to re-wet Can rob nutrients due

to high C:N ratio Attracts fungus gnats,

shore flies

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Caution1. Stay away from muck peat

2. Keep between 10 to 20% of mix

Pro’s Good MHC

Con’s Reduces porosity Not a nutrient source

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Caution 1. Keep around 5% of mix

2. Nutrient levels can vary from source to source

Pro’s Renewable resource

Natural slow release fertilizer

Good nutrient holding capacity

Good MHC

Con’s Reduces porosity Cost

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Lime◦ Fine grade needed, not agriculture grade

◦ Calcitic lime for Ca (>30 % Ca)

◦ Dolomitic lime for Mg (22% Ca, 13% Mg)

◦ Choose type based on needs

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Nitrogen sources◦ Plant based ◦ Seafood based◦ Animal basedCaution Notes: Can restart composting process, or

release of ammonia at first watering (seek professional advice)

Phosphorus (P) sources◦ Bone meal◦ Fish meal◦ Calphos◦ Bat and Seabird guano

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Potassium (K) sources◦ Kelp meal◦ Greensand◦ Wood ash◦ Sul-Po-Mag◦ Potassium sulfate (OMRI)

◦ “Compost “

Calcium (Ca) sources◦ Calcitic lime◦ Gypsum

Magnesium (Mg) sources◦ Dolomitic lime◦ Epsom salts

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Four Trials Conducted

1. Basil – No supplemental fertilizer

2. Tomatoes, Lettuce, Broccoli – No supplemental fertilizer

3. Broccoli -With supplemental feed starting 14 days after transplanting

4. Lettuce – With supplemental liquid fertilizer – starting day of transplanting

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April 3 – 23 756 (3”) pots, 42 trays – 13 mixes used

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Apr 18 - May 9 Trial 2 - 270 (4”) pots used 8 mixes used

Trial 3 – 90 (4”) pots used

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May 22 – June 7 90 (4”) pots used 8 mixes used

Picture taken day 7

8 greenhouse mixes used in all trials

1 control used in all trials

Weekly observations

Grower’s assessment

Computer randomizing utilized

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Laying out treatments according to computer selection

Types1. Seafood & wood based products (WBP)

2. Seafood & peat

3. Animal manures & WBP

4. Animal manures & peat

5. Hay, straw, silage

Inclusion rates◦ 5 to 20% in most trials

◦ 30% in one and 60% in another

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Component Used in how many mixes

Sphagnum peat 14

Peat Humus 5

Coir 2

Aged bark 2

Castings 3 - @ 4.5 to 5%

Perlite 11

Vermiculite 5

There were a total of 15 different mixes trialed

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Note differences in color and texture

No significant impact on performance from:

◦ Type of compost (with supplemental fertilizer)

◦ Compost inclusion rate

◦ Use of worm castings

◦ Coir vs peat

◦ Interchange of peat humus, compost & castings

◦ pH range (5.2 to 7.0)

◦ Levels - P, Ca, Mg

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1) Even with a wide range of mix configurations used and compost inclusion rates, (5 to 20%), the two items that consistently made positive impacts were when:

a. EC levels: 1.9 to 3.9 mmhos/cm

b. K levels: 200 to 250 ppm

2) All mixes (other than controls) required liquid supplemental fertilizer. Best results when started on day of transplanting

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Used at Strawberry Hill Farm – trial #4

◦ Day 1 & 8 – Rain Grow (4-2-3) chicken compost based fertilizer @ 1 oz/ gallon

◦ Day 15 – Neptunes Harvest liquid fish with seaweed blend (2-3-1) @ 2 oz/ gallon

Many other options available – check ACORN Inputs and Supplier Directories on-line

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Item Min Max Comments

pH 5.5 6.5 5.5 to 5.8 for starter mixes

EC (mmhos/cm) 1.9 3.9 <1.0 for starter mixes

Phosphorus (ppm) 1 20 ppm range in the trial mixes

Potassium (ppm) 200 250 Best performance range – Note: basil did well even at 500 ppm

Calcium (ppm) 60 380 ppm range in the trial mixes

Magnesium (ppm) 35 100 Ditto

Hort grade peat 0% 100% Grower’s choice - Feed & water will be needed more frequently

Coir fiber Sub for peat

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Item Min Max Comments

Compost 0% 20-25% The better the compost, the higher % can be used

Peat Humus 0% 20%

Aged Bark 0% 5-10% Economics will dictate its use

Castings 0% 5- 7 % Benefit: Long term crops

Combinations 0% 30–35% Compost, humus, castings

Perlite 0% 15–20%

Vermiculite 0% 5 – 10%

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NOTE:

1) Observations in this presentation are based on the 4

trials conducted between April and June of 2013.

Important Analysis1. pH: - keep in range of 5.5 – 6.5

2. EC: - 1.9 to 3.9 performed better

3. K: - 200 to 250 ppm for veggies,

higher seems OK for basil

Fertilizing1. Fertilizing - BEST to start day 1

2. Mix Fertility - Important to have in the mix, but

don’t rely on it alone

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Mix Components:1. Compost - beneficial to use, keep <20%

2. Castings - long term crops, <5 to 7%

3. Peat Humus - keep <20%

4. Combination – combination of above 3 items

kept<35%, or porosity impacted

5. Aged bark -caution, keep<10%, needs feed

6. Structure - needs balance of porosity &

moisture holding capacity

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“All composts are not created equal.” ◦ From: Tim Livingstone presentation on Mixes and

Transplants

Remember, just because a little is good, does not mean more is better.

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This section will provide some basics on:

◦ Critical elements for good composting

◦ Production methods

◦ Evaluation of a good compost

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Oxygen

Moisture

Food

Heat

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Factors which influence availability of oxygenPile size

Turning frequency

Turning method

Porosity

Oxygen availability determines compost typeAerobic, or

Anaerobic

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Moisture Range Acceptable - 40 to 65%

Optimum – 50 to 60%

• Squeeze/ feel test

Rules of Thumb◦ Higher during active stage

◦ Lower during curing stage

◦ Hot months - add water

◦ Cold months – keep it out

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Both Carbon (C) and Nitrogen (N) essential

Beginning C:N ratios: 20 & 40:1

Prevent N loss. Add soil (5 to 10%)

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High carbon sources Wood based products Cardboard & newspaper

Medium carbon & low nitrogen sources Hay and straw Leaf waste

Nitrogen sources Animal manures Silage, fresh green materials Yard waste Food processing waste

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Heating will occur naturally - IF there is a;

Good C:N ratio, and

Adequate moisture, and

Sufficient porosity

Active heating range: 50 – 65˚C

Turn when temps in this range

CAUTION: Excessive heat destroys beneficial microbes

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Turning windrowsFront end loader

Excavator

Straddle windrow turner

Farm manure spreaderPitchfork

Other methods include:

In-vessel systems

Static aeration with vents

Bins

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Critical Parameter Range/ Comment

pH 6.5 to 8.0

EC 3.0 to 6.0 mmhos/cm

C:N ratio 15 to 25:1 (when finished)

Smells Like a good forest soil

Appearance No original substrates recognizable

Temperature Will not reheat if moisture is brought to 50 –55%

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NOTE: To be sold, must also meet CCME

Guidelines for Heavy Metals and pathogens

Need to Know: Analysis: pH, EC, K levels

Compost type, % used

Percent of non peat ingredients

Structure

Remember: start fertilizing early

Advice on making your own: Start small, trial, test

Don’t switch until proven

Enjoy!

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