Seville In-house Full-day Educational Program

Posted on Categories Growers, Integrated Pest Management

Mr. John Wilson arranged with the help of some sponsors a full day of green industry professionals to provide talks for their growers on June 15, 2018 in Mansfield TX. John was kind enough to invite me and allow me to share detailed notes from the meeting with other grower in the industry. Below are the notes provided as taken. Disclaimer: the notes below do not represent endorsement, research, or vetting by Texas A&M AgriLife Extension and the AgriLife IPM Program Specialist Program. Notes below as provided as is from the speakers who provided the information.


Dr. Anne Chase – Plant pathogens| Chase Agricultural Consulting, LLC.

Rick Fletcher, Technical Services Manager – Insect and mite IPM | NuFarm

Gary Vollmer, Global Product and Technical Manager – Rooted Poinsettias & Pathogens | Ball FloraPlant

Will Healy – Poinsettia Propagation & Potting MediaBall FloraPlant

Paul Pilon, Hort Consultant – Avoiding Common Blunders | Perennial Solutions Consulting

Dr. Anne Chase

  • Doing trials again. New greenhouse for trials
  • Topics going to be covered:
    • Edema
    • Thielaviopsis – preventative, curative and cultural methods
    • Pythium and Phytophthora
    • Fusarium issues on mums
    • How to achieve the best bang for your buck in a fungicide rotation
Always less costly to prevent a disease than to treat it afterwards.
  • perhaps hard to see it upfront, but always most costly treating curatively.
Most fungicides will impact the plant in some way. Don’t think that applying more fungicides is better; can have detrimental impact on plant health.
If Anne Chase recommends something and it doesn’t work on your operation, she is very interested in knowing what went wrong/why it didn’t work.
  • looks very different from crop to crop.
  • black spots, discoloration, bumps on the leaves, bumps near the stem, under surface of leaves, etc. depending on the crop
  • List of plants rather vast, from Anthurium, cabbage, ivy geranium, yucca, etc.
  • Edema is not the same thing in all the plants
    • Some plants its water and some is light
    • “Intumescence” on tomato due to lack of UV light (i.e. in LED lights). Can be fixed with addition of UV
    • “Oedoma” on geranium (high light intensity, low nutritional levels, high soil moisture, and high humidity)
    • Conclusion: similar symptoms being caused by very different conditions
      • Stopping symptoms based on the exact issue!
    • More artificial growing conditions increase these types of physiological problems
Black root rot prevention
Growing pansies in the middle of the summer – results in all the pathogens!
  • Best product for black root rot protection: 3336
  • Verando O / Affirm: Just as good or not quite as good as 3336
  • OHP 6672; confirmed works really well
  • Tourney fungicide; also works really well (don’t drench pansies with these! Can have phyto effects; dose-dependent different from crop to crop)
  • Do not reuse flats or pots
  • Most fungicides have some side-effects
  • Control shoreflies!
  • Clean growing area after each pansy crop: Strip it – KleenGrow are the best
  • It is critical to minimize stress on these out-of-season pansies – too hot!
    • If you have to due to market demands, you just need to spray regularly
  • Keep the potting medium pH near 5.5 to minimize black root rot (<- cannot grow black root rot in pH 5.5)
Cautious about using less than the label rate;
  • If you use 50% rate, and the half-life of the product is low, then you end up with even shorter period of effective control
Mode of action of a fungicide: if it’s a cell division inhibitor, it won’t kill the fungus. It is preventative
Affirm (8 oz / 100 gal) half-life is 7 days; but kills the fungus! Good thing to start with and then go back to preventative insecticide
3336 (16 oz / 100 gal) at 2 weeks later for preventative.
As plant starts to get larger and you’re watering more often, increased risk of Phytophthora. Use preventative against phytophthora
Need to decrease GH temperature – shade cloth
Thielaviopsis rotation
  • OHP-6672 and 3336 (1-thiophanate)
Weather increases oomycete diseases in South Florida (TREC team UF)
2012 – 2013
Total Samples
2015-2016; year with hurricane. Increase in disease instance! If you over-water, you are creating these conditions
Pythium root rot on poinsettia
  • Use a higher rate at the correct interval, works better than very low rate less often
  • Empress higher rate worked really well
  • Heritage & Mural also work well
Use Strip-It/clean area at least once a year
Pythium rotation (Poinsettias & other ornamentals)
  • Subdue MAXX consider adding KleenGrow to control resistant strains (we have them in Texas)
  • Segway O
  • Terrazole or Truban or Banrot
  • Rootshield Plus
  • Mural OR Empress Intrinsic
Phytophthora crown rot on Gerbera
  • Segovis 2 oz / 100 oz and Mural at 3 oz; good rotation
  • Segovis, put out in the right conditions, can provide about 3 months control!
If no resistance, Subdue MAXX Works really well, but be cautious of resistance!
Fungicide rotation for phytophthora:
  • Adorn
  • Aliette
  • Segway O
  • Micro, Stature, Orvego
  • Terrazole, Truban, Banrot
  • Segovis
Segovis; work really well on downy mildew
  • plugs treated
Fusarium stem rot – F. solani
Two different diseases on mums caused by fusarium:
  • stem rot
    • stem rot early
    • stem rot scattered in pot
    • fusarium growing on outside of stem (pinkish-white)
    • if it’s at the base of the stem, you can treat it. If you already have the pinkish-white, can be too far long
  • Fusarium wilt (F. oxysporum fsp chysanthemi)
    • Single cutting affected
    • Completed wilt/collapse of the cutting
    • stunting
  • Rhizoctonia also very similar symptoms
  • The above three can all look very similar, but need to identify correctly; rotation very different between the three.
Fusarium wilt disease
  • infect the vascular system of specific crops (often only a single genus)
    • symptoms include yellowing, wilting, and collapse due to clogging of the xylem and production of toxic compounds that damage the plant
  • In the absence of its host crop the pathogen can persist for years and even reproduce on roots of a wide range of crops and weeds
  • Certain forms of nitrogen and maintaining soil/medium pH still most effective means of reducing Fusarium wilt
    • nitrate is safe and ammonium is not <- works way better than fungicides
    • Works in soilless and soil media
Fungicides for fusarium:
  • Heritage and Medallion work consistently well
  • Daconil also works excellent consistently, works well ABOVE GROUND only (applying to roots will kill the plant)
  • Empress and Orkestra; work very well, but need more trials
Don’t let the plants wilt!
  • plant stress will increase instance of fusarium wilt!
  • Overwatering will result in other pathogens taking over
Plant pathogens – water potential source?
  • i.e. ponds/water tanks
  • In Colorado; found fusarium in the water (and during certain times of year, can increase in fusarium loads)
  • Anne; not a lot of evidence that plant fungi will move around in water
    • Most of the time, treating the water is meaningless
    • However, need to do it, to mitigate the risk of contaminating all the crops
    • ‘uptake’ considered most effective (work by Dr. Karl Steddom)
Use the very best product you can use, as wide as you can, at the labelled rate.

Rick Fletcher, Nufarm

123 test in the US that NEED to be conducted if a product is labelled for use outdoors
60% of NuFarm business is herbicides
Work a lot with the Japanese and Koreans, who are most active in the pharmaceuticals in the world
  • Manufacture all of our their products in the US. Mainly in the US
Role of scouting in production: principles and practice
  • First part of integrated pest management
  • Via monitoring, determine where and when treatment is needed
    • Needs to be measurable and repeatable
Tools used in Greenhouse IPM
  • The list of essential monitoring tools includes:
    • Trained personnel
    • If something doesn’t look normal; someone will look closer and try and identify why
    • Hand-lens and head lens
    • yellow sticky cards, clothes pins, bamboo stakes
    • flagging tape
    • Record-keeping system
    • Individual maps of all greenhouses
    • Support labs
Scouting & IPM
  • One month prior to the introduction of a crop, evaluate entire greenhouse, inside and out
    • Note presence of weeds in and around greenhouse
    • Crops growing in adjacent greenhouses or outdoors should be recorded
  • Previous pest problems in the greenhouse and current pesticide application methods
  • At time of arrival or sooner thereafter, the scout should inspect one-third or more of the plans
    • thoroughly examine plants for signs of insects and diseases
    • early detection and prompt action can minimize the spread of insects and diseases and save pesticide applications
  • Yellow & blue sticky cards; only capture flying insects. Adults thrips, winged aphids, adult whiteflies, fungus gnats, etc.
  • Monitor cards weekly
  • Cards near the floor; for insects that have a part of their life cycle is near the floor (?)
    • shore flies and fungus gnats
Indicator plants; chosen from pest-infested plants in a greenhouse
  • scout uses these plants to make a close, ongoing examination of a pest’s examination of a pest’s development through its life cycle
Mite Management
  • mites feed on the leaves, fruit and tissues
  • Life cycle can be very short
  • Typically not detected until plants are already damaged (very late)
  • Environmental conditions can cause mite populations to explode
  • Stippling damage, cause chlorosis
  • Yellowing, necrosis and defoliation
  • Presence of webbing
  • Kontos can work as a systemic; slow kill & works against small spider mite populations
Things to consider:
  • What species of mite do you have?
  • What life stage are they in?
  • What products are labelled for your mite and your site?
  • What are the environmental impacts? ; typically harm your beneficials
Common mite pests:
  • Twospotted spider mite is a very common one.
  • Eriophyid mites
  • Cyclamen and broad mites
TetraSan 5 WDG
  • Translaminar
  • Sterilizes adult females, kills eggs and immatures
  • control spider mites and certain red mites
  • Good longevity and soft on beneficials
Floramite also an effective control
  • Abamectin product that is water soluble
  • Labeled for:
    • mites, tarsonemid mites, eryophid mites, etc.
  • Local penetrant and contact insecticide
  • Mixing with hort oil (when its cool) works very well
  • Synergistic effects with:
    • Etoxazole
    • Bifenazate
    • nematodes
  • Antagonistic with:
    • Azadirachtin
    • Spinosad
    • B. bassiana
  • Thrips can be a major issue
  • Identification is vital. Feeding location can be different depending on the species
  • Efficacy can change based on species and chemical location properties
Thrips are tiny
  • rasping and feeding
  • similar bronzing and stippling
  • cause: deformed leaves, decaying flowers, slivery, flecked scars
  • curling of flowers
  • Adults feeding on the pollen in the flower
    • nymphs feeding on leaves and stems; causing actual damage
  • Vectors of many plant viruses (tospovirus)
Thrips feeding usually accompanied by black varnish like flecks of frass
  • can move readily across long distances via air
Thrips threats:
  • Western flower thrips
  • Tobacco thrips
  • Chilli thrips
  • Greenhouse thrips
  • Onion thrips
  • Orchid thrips
Thrips pupal stage is often in the soil
Western Flower Thrips
  • Develops in 14 – 30 days
  • 1 to 2 mm long
  • tubular shaped
  • nymphs are wingless
Greenhouse thrips
  • Foliar feeding
  • Similar life cycle to western flower thrips
Chilli thrips
  • about half the size of western flower thrips
Echinothrips americanus
  • rising threat
  • feed on leaves
  • black with white on the top of the wings
IPM Strategies
  • Conserve, Pylon and Overture
No magic bullet; must apply in intervals
  • 3 applications to get control because of life stages in leaf and soil
Efficacy data from IR4
Excellent control:
  • conserve
  • Mesurol
  • Overture
  • Pylon
Use of beneficial nematodes? – i.e. nemaysis
  • for pupal stages. Need to confirm efficacy
  • A. swirskii
  • Orius
  • some other predatory insects
  • last over a year in the soil!
  • That’s why it’s only available for use indoors
So we have scouted, identified, made product choice and time to spray:
  • How are you getting an even application?
  • How are you getting mites under the leaves?
Can use water sensitive paper to determine coverage
Can increase coverage using non-ionic spreader:
  • using a “sticker” with a penetrator, you will inhibit the chemical’s ability to go into the plant
Any product registered outdoors:
  • need three pollinator tests: oral, dermal and colony kill test

Gary Vollmer | Rooted Poinsettias & Pathogens

Sanitation strategy
  • Disinfest or clean all surfaces in cutting handling areas and propagation areas
  • Worker hand sanitation
  • minimize pooling on leaves
  • if using overhead misters, cycle on for shortest time possible
  • contribute to poor rooting (big ball of callous and no roots)
  • Use CapSil or other wetting agent to increase wetting efficiency
If you get a large ball callus, its too wet. If its large and brown, then its way too wet
Propagation: Late disease and insect control
  • fungus gnats can still be problematic
  • whitefly now take priority for monitoring and control
  • fungus gnats and pythium go hand in hand!
Phosphorous deficiency
  • yellowing on leaves with brown blotching
  • no phosphorous on leaves coming out of propagation
  • We have “phosphobia” with poinsettias because of phyto if applied to the leaves
  • Consider 13-2-13 in propagation and then once potted up, need to give phosphorous! Can also do 20-10-20, as long as you rinse it off the tips of the poinsettia. You have minutes to wash off, not hours!
  • Lack of phosphorous – plant won’t grow!
    • Need balance. No phosphorous = no growth. Too much phosphorous can cause damage to growing tip as well
    • One solution; water with feed (over top), then come back over and “wash” the leaves off (non-feed) water
    • Need to do quickly. New growth is like a “cup”, if it evaporates with phosphorous, that’s how you’ll get the damage.
Must keep pH lower than 6.6 in media
Hydro-fiber issues on pH and calcium nutrition and moisture?
  • as non-peat based components replace peat, so change the chemical and physical structure of your media
  • less lime in media as hydro-fiber is less acidic
  • irrigation practices needs to be adjusted
Need to really pay attention to the nutrition in the first month of the poinsettia crop
Salt toxicity (sodium chloride)
  • keep chlorine <70 mg/L
  • bleaching around the edge of the leaf
  • often misdiagnosed
Magnesium deficiency
  • As pH increases, plant can grow hungry for magnesium
  • discoloration of leaves from the edge inward between the leaf veins
Nitrogen deficiency
  • light green
  • Not common
Calcium deficiency
  • Can get it early if pH is low or have poor roots
Iron and/or Manganese toxicity
  • low pH + high feed
  • Iron toxicity
  • Yellowing edges
If the media is very dry, especially before transplanting, then the lime in it hasn’t been activated yet and the pH can be low.
Molybdenum toxicity
  • Very rare
  • yellowing edge and moves into the leaf
N, P, K deficiency; show near the bottom of the poinsettia initially
Heavier molecules; Ca, B, and Mo deficiency, shows in the upper part of the poinsettia
Florel application prior and post-pinch (Florel sandwhich)
  • applications of florel 5 days prior and 5 days after the pinch
  • Can cause a PGR effect that will continue through the crop cycle
  • Rates from 200 ppm
  • Not necessary on many new very free branching varieties
Pinching key tips:
  • stack your nodes before the pinch
  • don’t leave too many leaves, know your specs!
    • this can cause wide plants and smaller bracts
  • the growing environment just prior to, through two weeks after the pinch, is critical
  • High humidity is needed to develop the branching evenly
    • misting, quick boom passes, wetting floors, etc. are all useful tools to achieve this higher humidity environment
  • 10 – 14 day after transplant
    • medium pinch.
Early PGR applications
  • About making the whole plant even!
  • Cycocel 500-1000 ppm spray for cooler regions
  • Drench will impact all shoots evenly; not what you want! You want upper ones to be more suppressed than lower to get even growth
  • first two you do after your pinch will be the most important; you want to manipulate the architecture
Moisture management
  • Focus on:
    • Building your foundation
    • Stay in the middle of the road; do not cycle too dry
    • Creating a consistent language of moisture levels within your growing team
  • Avoid:
    • Don’t let it wilt! First thing to damage in poinsettia are the roots
    • Don’t “cycle” dry; want to stay consistently moist (not “wet”, but modestly moist)
    • Big swings in moisture management
    • Guessing when and how much water
    • Overhead watering late in the day
Letting them dry and then water -> induces pythium!
  • Attacks at or just above the soil line
  • often misdiagnosed as pythium
    • rootshield WP/rootshield plus
    • Actinovate
    • Cleary’s 3336
    • Medallion
    • Heritage/Empress
  • can attack pre-space when canopy is closed
  • When pot-tight and overhead irrigating, Botrytis can become a problem
  • Usually starts with leaves but in a closed microenvironment can attack stems
    • Cease
    • Pageant
    • Palladium
    • Medallion
    • Decree
    • Cleary’s 3336
  • Often follows fungus gnat infestations
  • avoid cycling moisture from wet to dry
  • sloughing roots
    • rootshield/rootshield plus
    • subdue maxx (watch resistance)
    • Segway (<- very impressed)
    • terrazole/Truban
    • Heritage
    • Aliette
Powdery Mildew
  • Can attack pre-space when canopy is closed
  • See more every year!
    • Actinovate (spray)
    • Cease
    • Pageant
    • Eagle
    • Milstop
    • Phyton 35
Fungus gnats/shore flies
  • keep the floors clean
    • shore flies not considered a major issue, fungus gnat larvae will feed on the roots
  • larvae of fungus gnats feed on roots and callus
    • vector of pythium?
    • best control is sanitation
    • IGR insecticides early
    • open up the cutting by cutting longitudinally, and look for chewing marks near the callus
  • Bemisia tabaci/sweet potato whitefly/silver leaf; Q biotype becoming a major concern!
  • Greenhouse whitefly (different species); not as big of an issue
  • Banded wing whitefly; Trialeurodes abutilonea. Has bands on the wings.
Scout, scout, scout!
  • use traps
  • identify your whitefly
  • find hotspots
  • outside pressure?
  • biocontrol?
  • non-neonic?
Seen examples of growers that used dips with bioinsecticides and resulting in full operation having Erwinia!
  • Some growers dipping in fungicide and bioinsecticide; have to deal with the REI and others issues, but its one potential strategy for early management
Grower down south near cotton fields;
  • found really good control using Altus and Mainspring on whiteflies
Space on time!
Watch out for herbicide drift/herbicide damage

Will Healy | Poinsettia Propagation & Potting Media

Post Harvest unrooted cuttings Handling
  • unrooted cutting (URC) quality and rootability is directly related to store carbohydrates
    • Good light, good growing conditions
  • Unless you’ve cut that cutting, the cutting is stuck with the carbohydrates it has!
  • Reducing the temperature maintains carbohydrates
    • when carbs are all done, leaves go yellow, roots don’t grow uniformly, etc.
  • Have a staging area (i.e. cooler; about 48 – 50ºF for poinsettia cuttings) to keep cuttings before shipping/moving for sticking
  • Cool post harvest handling conditions restore hydration (turgid)
    • if you stick non-turgid cutting, you have delayed or inhibited rooting
    • Getting this wrong will greatly increase rate of failure!
  • humidity in storage, paper wrap (wet paper towel) and into a plastic bag during shipping; keeps them hydrated in shipping
    • from time of cutting to time of sticking, what are we doing to prevent the cutting from drying out?
Dips during propagation to control mites (et al.)
  • Oils
    • Horticultural oil (ultrafine)
    • Neem
    • Rosemary
  • Mode of action (MoA)
    • Blocks breathing holes (spiracle & trachea)
  • Compare spiracles of arthropods (i.e. insects and mites) to stomates of plant leaves
    • Dip with oil may suffocate the insect, but you could also suffocate the plant
  • Heavy cuticles = less phytotoxicity
  • Dry time is critical = FAST IS BEST
  • Coverage is critical – no contact = no kill
  • if not oil, what else?
    • Coverage is complicated
    • spray as soon as URC are turgid with leaves UP
    • thoroughly spray using a wetting agent if appropriate
    • what about biocontrols?
Root initiation basics
  1. Rooting hormone (auxin) stimulates callus formation
  2. Callus is undifferentiated cells that pile up in the stem like little grains of sand and expand to the outer epidermis
    1. stem swelling
    2. callus balls on base of unrooted cuttings
  3. Callus ‘loosens up’ the cell to allow the root to rapidly elongate through the stem
  4. Root develops from vascular bundle and elongates through loose callus tissue
Rooting hormones:
  • IAA – best, but not water soluble or light/water stable. Need to apply it in alcohol. Not long lasting in a jar.
  • IBA – light stable and water soluble. If mixing up liquid IBA, keep it in the dark when not in use to keep it stable or mix up a new batch each time.
  • NAA – stable, most effective for woody plants
Hortus K-IBA
  • Widely used, other formulations talc based & not water soluble
  • 100 – 200 ppm drench after sticking
  • make sure URC are turgid prior to application
  • apply sufficient volume to run down stem
  • apply in both directions to coat both sides of stem
  • slow or uneven rooting? – re-apply rooting hormone (as a drench with specifications above) by day 3 – 5
People sticking:
  • try to limit how many people are doing it and remove “distractions”
  • More people = more variation in quality and method of sticking = less consistent result
Media Profiles “Structure & Ballast”
  • Ballast – Sufficient weight (soil+water+container) to keep the plant standing upright as it dries
    • water is critical here and getting soil that helps manage the water
  • Structure. Three components:
    • Physical: aggregation and structure, surface sealing, compaction (no air pockets = no root growth), porosity, water movement and availability
    • Chemical: pH, Soluble salts, sodium, nutrient holding capacity, nutrient availability, carbon:nitrogen ratio
    • Biological: macrofauna, microfauna, microorganisms, roots, biological activity, organic matter
What do add to the mix?
  • buffering capacity is key!
    • Limestone is the tool, form is the trick!
    • ‘Hydrated’ no buffer, pH only <- can result in dip in pH after increase!
    • ‘Carbonate’ buffer +pH control <- this is what you want
  • Grit controls the rate of release
    • finer the grit (higher number), the faster the reaction and shorter the benefit
  • Other additives?
    • Slow release
    • Micronutrients+phosphorous – top dress is a waste! It’ll leach out very quickly
  • identifies trends & changes behavior
  • Collecting data that is not actionable is a complete waste of time (and money)! Need to make a commitment to start monitoring to change behavior
TCM (Total Crop Management)
  • Don’t worry about today’s problems if you worried about it last week!
  • Not monitoring only for insects and plant pathogens! If you do that, you have “blinders” on, ignoring other critical production problems
  • pH & EC monitoring
    • reduce plant stress – malnurished plants = insect & disease magnets
    • identifies slight shifts in production – early warning of problems in 2-3 weeks
    • ‘spotlight’ production – “if you monitor, you improve”
    • QA program – quality in = quality out
  • Boundary management, not absolute values
    • set min-max values for specific problem
    • Develop clear strategies for control when at different points on graph
      • Apothecary of chemicals for specific control strategies- control costs, increase control
      • IRAC & FRAC relevant to avoid resistance
      • bio-strategies when appropriate

Paul Pilon | Avoiding Common Blunders

Hort consultant in perennials
  • 60% consulting and 40% contract research (from different companies)
Pageant Intrinsic Benefits the plant
  • Verbena trials: Pageant 4 oz / 100 gals applied after sticking increased rate of rooting and better tip growth. These results are mainly seen when propagation plants are stressed.
  • Worth doing a trial with pageant in propagation to see if it helps with root and plant growth
  • Has had great success with Pageant on poinsettias: 4 oz / 100 gallons applied after sticking
    • benefits observed at 4 – 8 oz per 100 galls (spray)
    • Sprays @ 4 oz / 100 gal – rooting benefit only
    • Sprays @ 8 oz / 100 gal – rooting benefits & disease
    • Most growers are applying 6 oz / 100 gals
  • Thiophanate methyl
  • Affirm
  • Terraguard
  • Orkestra
Starting materials: it all begins here
  • poor quality starting materials will lead to production and quality issues
Watch for discoloration/mottled appearance within a tray
  • sign of some kind of root rot
  • over grown liners
  • lots of growth at the base of the plant
  • bacterial disease
  • Throw it out!
Aster Yellow
  • vectored by plant leafhopper
  • transmitted last season
Quality control
  • inspect plugs/liners upon receipt/prior to potting
    • weeds, insects, foliar diseases, virus symptoms, rhodococcus and etc.
    • inspect roots
    • observe variability within the tray
      • size and/or coloration differences
    • seek credits from supplier immediately!
If you’re spraying glyphosate, may need to go back 2 – 3 weeks later to spray again! Prevent the labor cost of having to spray over and over by also putting down a pre-emergent
Variability of liner sizes:
  • crops started with variable liner sizes generally do not even out
  • the smaller plants grow more slowly
  • the larger plants grow at faster rate
  • but the small stay small!
    • Consider isolating all small plants into their own small trays and/or removing, to retain high quality inventory
  • take the loss in the plug! Removing/not moving a plant later because it never grew even in size with the others is more costly (labor, potting media, bench space, etc.)
Most liners should be planted so the top of the liner is at or just below the soil level
Do not bury the crown when planting these perennials:- Aquilegia, Brunnera, Campanula carpatica, Delphinium grandiflorum, Digitalis, Erigeron, Gaura, Heuchera, etc.
Planting bare root
  • plant most perennials from bare root so the crown is no more than 1/2 to 1 inch below the media surface
  • many perennials from bare root grow better when they are planted ‘high’ – with the crown 1/4 to 1/2-inch above the media surface
  • Do NOT bury the crowns too deeply
Improper filling and initial watering
  • pots slightly over filled (waste of potting media)
  • more importantly the initial watering was too heavy (results in algae production)
    • finner droplet size or decreased flow rate will provide more even initial watering.
Irrigation groupings
  • where possible, group plants by irrigation requirements
  • try to place plants of similar age together within the same irrigation zone
  • Avoid placing new plantings directly next to older established plants (consolidate old plantings together to free up irrigation zone just for new plantings)
Properties of growing media
Particle sizes of growing mixes
  • all particle sizes are important
  • fairly equal proportions of each particle size maintains adequate air and water in the root zone and allow for optimal root development
  • Can use a sieve analysis to determine particle size distribution (example provided for sieve results of a bark growing mix)
  • Growing mixes can cause a problem if there are too many small particles (<1mm)
Porosity of growing mixes
  • growing mixes consist of solids, liquid and air
  • goals for optimal plant performance
    • after drainage:
      • 35-55% solids
      • total porosity: 45 – 65%
      • 15 – 25% air space
      • 30 – 40% wate retention
To promote optimum plant growth, container substrates must provide a proper balance between air space and water availability
  • Many benefits are observed when this balance is achieved
    • Plants establish quicker
    • crops can be gron in less time
    • improved uniformity
    • fewer plant losses
    • better plant quality
    • reduced production costs
    • increased sales & profitability
  • In instances when I observe delayed establishment/rooting and crop variability, the physical properties of the growing mix are often less optimal
Purpose of plant growth regulators
  • to produce high quality plants of desirable shape and size
  • improve plant quality & uniformity
    • deeper color
    • strengthen stems
    • plant height impacts perceived quality
  • may increase disease resistance
  • increase stress resistance
    • have less shrinkage
  • control plant growth
    • less space used per plant production
    • can meeting shipping requirements
    • longer shelf life
  • Volume is critical
    • Increase volume = increased growth regulating effect
  • Better to apply lower rate multiple times than to apply higher rate once
  • Always apply PGRs from two directions; otherwise some parts of the plant get more exposure than others
  • Always leave some plants with no PGRs to confirm that its working and as comparison

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