avoid common mistakes in poinsettia production.pdf

7/27/2019 Avoid Common Mistakes in Poinsettia production.pdf

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2995 Wilderness Pl., Suite 102 Boulder, CO 80301

Phone (303) 415-1466 Fax (303) 415-1605 Email: [email protected]

Avoid the Most Common Mistakes in

Poinsettia Production

1.Propagation2.From Planting to Pinch3.From Pinch to First Spacing4.From First Spacing Until Three to Four Weeks Before

Market

5.The Last Three to Four Weeks of Finishing6.Shipping


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Most Common Mistakes

in

Poinsettia Production

1. Propagation: Most important problems: Lack of shade, too

much mist, too hot: The single most common,

most importantand costly mistake made duringpropagationis that the cuttings receive too much

mist in the first eight to ten days. The main reasonfor this is that growers try to compensate wilting

caused by too much light with applying more

mist. The consequences of too much mist are:

a. Losses due toErwinia two to five days aftersticking

b. Losses due toRhizoctonia five to ten daysafter sticking

c. Botrytis infections of stem and leavesd. Bleaching of the foliage due to leaching of thenutrientsIt is extremely important to heavily shade the

poinsettias during the first eight to ten daysespecially under hot and sunny conditions. This

leads to lower temperatures and less need for mist.

It is mandatory to have movable shade, so you canadjust to cloudy weather. Too much shade can

also be a problem especially under humid and

cloudy conditions. The ideal initial light levels

should be at 700 900 foot candles. Once the

cuttings develop a good callus and begin takingup some water, the shade should be slowly

reduced, to adjust the cuttings to higher lightconditions.

Fine tune the mist hourly: Many times the mistis not fine enough and the adjustments of the

misting cycle are not done sufficiently. The plantsshould be checked, and the mist adjusted if

necessary, every hour. Poinsettias can flag a littlebetween 12 to 3 PM., but should never be water

logged. They should always be turgid and almost

dry in the morning, except the first two morningsafter sticking, when they can be moist.

Avoid damage with rooting hormones: Veryoften the cuttings are dipped too deep into the

rooting hormones, which can result in burning of

the stem. Only the actual surface of the cut should

be immersed into the hormone.

Start fertilization program early: Many timesthe first leaves that develop on a rooted cutting are

yellowish green, caused by lack of fertilizer. The

first feeding can be done ten days aftersticking

with100 ppm N. Once the roots begin to form150 ppm N and then 200 ppm N should be applied

once the cuttings are fully rooted. Stay away fromphosphorus applied over the foliage as this can

stunt the young leaves.

Clean bad leaves off the plants everyday: Manycuttings are lost because of insufficient cleaningand consequential problems withBotrytis,

Erwinia, andRhizoctonia.

Use the right fungicides as a preventativerather than as a cure: In addition to the daily

cleaning of the badleaves, most of the problemswithBotrytis can be reduced by applying a

combination of Daconil and Dithane (Decree alsolooks very promising) one day after sticking and

six days later. Medallion and Terraclor work well

againstRhizoctonia.

Make sure cuttings dont stretch! Cuttings withstretched internodes of more than 1/4 to 1/3 of an


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2995 Wilderness Pl., Suite 102 Boulder, CO 80301Phone (303) 415-1466 Fax (303) 415-1605 Email: [email protected]

inch, will result in uneven plants that have some

bracts develop below the canopy of the main

bracts. Use growth regulators moderately when

you see new growth. Reapply every five days asneeded.

2. From planting to pinch: The number one problem during the whole

crop cycle is poor quality media!

Most problems are caused by poor quality or fine

peat with insufficient structure. The mainconsequence is lack of oxygen in the root zone

which results in less resistance to pathogens,

weaker root development, restricted nutrientuptake, and lack of vigor. The same problem can

occur by using poorly composted bark.

Do not plant all varieties at the same time.Compact varieties, like the Silverstars,need two

weeks more growth time than medium vigorousvarieties. If earlier planting is not possible, they

can be pinched at planting. Vigorous varieties can

be pinched or planted and pinched one week later

than medium vigorous varieties.

Get water, fertilizer solution, and soil analysistwo weeks before planting: Very often growers

find out too late that there was a problem with themedia to begin with, even though they got it from

the same source. Problems with the water or the

fertilizer are usually detected too late.

Start feeding early. Very often poinsettias lackfertilizer in the first two to three weeks after

planting. This results in stretchy, soft, under

nourished (calcium-deficient) plants with the final

result of stem breakage at the end of the crop.

Start growth regulating early. As soon as thepoinsettias begin to grow, start making weekly

growth regulator applications to avoid soft tissue

and stretchy first internodes. The branches withthese stretchy internodes are usually the ones that

snap off at the end of the crop.

Provide sufficient light. After propagation,poinsettias are very often shaded too much for too

long early on. This leads to thin cell walls andlater to stem breakage. Ideal would be 2500 foot

candles early and 4000 5000 foot candles later.

If hot, only shade the first seven days afterplanting and one day before to seven days after

pinching. If needed, mist the plants to reduce

stress rather than apply too much shade.

Keep the night temperatures high. Many timesnight temperatures are too low early on, which

results in slow root development and consequent

weak and stretchy growth. The night temperaturesshould ideally be at 72-74

oF until three weeks

after the pinch, as long you are not in the short

days. After that, they should be slowly reduced to68 oF.

3. From pinch to first spacing five to six weekslater. Pinch on seven to eight leaves to achieve

five to six fully developed branches. Too many

branches all too often result in stem breakage

problems. As the outer branches search for light,they have to grow side ways and because of the

wider angle tend to snap off easier. Also the more

branches that are on the plant, the thinner they areat the bottom.

Pinch higher if branching is poor. Certainvarieties can be more prone topoor branching,

especially if the stock plants were stressed.If the

little buds are missing inthe leaf axis, branches

will not develop.

Remove the top leaves at the time of pinch.This should be done for a variety ofimportant

reasons. For one, the top branches will developslower which will result in a more even canopy.

The increased light level for the developing lower

branches will result in stronger stems with shorter

internodes. Furthermore, the branches will growmore upright, as they dont have to grow to the

side in search for the highest light level.

Avoid early spacing. Pinching and spacing at thesame time may be convenient, but it is the mainreason for stem breakage. This is especially true

on plants that are taller than 14 inches and

varieties with a wide habit. Poor plant structureresults if the poinsettias are spaced out too soon.

With too early spacing, the developing branches

tend to grow towards the highest light intensity

(which is towards the side), and because of that,tend to develop horizontal shoots which are the

most prone to snapping off.

Provide high light conditions. As indicatedabove, high light conditions starting at seven days

after pinching will result in thicker and stronger

stems with shorter internodes, and consequently inless stem breakage.


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Avoid light intrusion and night temperaturesabove 70

oF. Most inconsistencies in flower

induction are caused by pockets of warm air

during the night time, which can be prevented bygood air flow.

Provide sufficient calcium. Calcium levels areusually too low, especially early on. Calcium

should be at 150 ppm in the soil and 1.2 - 2 % in

the leaves. Stem breakage is usually more of a

problem with low levels of calcium.

Perform complete soil analysis at least everytwo weeks. Most of the severe and very costly

problems can be avoided, if the soil is checked ona regular basis. The cost and time of performing

soil analysis, or letting a lab service handle it,

should not be an issue. Check salts and pH

weekly. The EC should be at 1.6 - 2.2 mS/cm andthe pH at 5.8 to 6.0 using an SME procedure.

Keep night temperature at 68 oF. Many timesnight temperatures are kept between 62 to 65

oF to

save money. The consequences are weaker rootsystems, thinner branches, reduced growth, longer

internodes, and more problems with Pythium,Botrytis, Powdery Mildew andRhizoctonia.Seventy-two degrees in the first three weeks after

pinching results in a stronger root system,

stronger branches, and more even branching. Thisis especially the case if combined with a good

fertilizer regimen, high light, and good growth

regulation (and if possible, day temperatures of 68

to 70oF).

Growth regulate once a week. The majority ofthe growers apply growth regulators three weeks

too late and not frequent enough. This often leadsto stretched first internodes, irregular plants, and

stem breakage. Weekly growth regulation at low

rates starting ten days after planting will lead to a

better habit and stronger stems as long as theplants are actively growing. Once the leaves get

small and dark green, the growth regulating has to

be reduced. The effect of growth regulators isoptimum if night temperatures are high, the root

system strong, and the feed level good.

Florel at 350 ppm instead of other growthregulator treatments, one week before and one

week after pinching, will lead to a more even

habit.

Ammonium should be 30% of total nitrogen. Ifammonium levels are low, the branches get thin

and the leaf expansion will be insufficient.

Use some kind of graphical tracking system.Too many crops end up beingmore than 1 inch

too short or too tall.Weekly assessment of theheight ofthe crop is the basis for exact growth

regulation.

Make lots of tests with insecticides. Applynormal and double rates to see how potentialdamage would look. Make the same test in the

morning at noon and in the evening to see the

effect of different climate conditions.

4. From the first spacing until three to four weeksbefore the end of the crop.

For the ideal V-shape, space, when the plantsstart to grow into each other. Manypoinsettias

are spaced too early. Toachieve the ideal habit,the poinsettias should be kept pot tight and growth

regulated at the same time up to five to six weeksafter pinching. If possible, space twice before the

final spacing.

Provide high light conditions. Too much shadeoften leads to stretchy, unevenplants with small,

open bracts. The ideal range of light levels is from4000 to 5000 footcandles.

Spray calcium chloride. Lots of growers battlebract edge burn and many consumers still have to

live with it, although weekly applications ofcalcium chloride can strongly reduce the severity

of the problem.

Keep night temperatures at 68 oF. Nighttemperatures of 62 to 65

oF will result in more

fungus problems and stretchy growth.

Provide good airflow and heat distributionMost inconsistencies of the bract color are caused

by uneven heat distribution combined withuneven moisture level throughout the crop.

Ammonium should be 15% of total nitrogen.Very often ammonium is cut out too early in

October, which results in small bracts. On the

other hand, ammonium levels kept at 30 % ormore throughout October can result in too soft

growth and bract edge burn.

Change the way you growth regulate. Checkyour graphical tracking system twice a week.

Cycocel at 750 ppm can be used at alltimes.

Grow with negative DIF (no lower than 60oF for


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two hours after first light and 65oF during the

day) instead of chemical growth regulation. Wait

with a Bonzi drench (rates see below) until three

weeks before shipping in the north and four weeksbefore shipping in the south. Do not regulate the

growth by keeping the plants dry; the roots will

suffer and the bract size will be reduced.

Spray against powdery mildew. Powderymildew problems are on the rise. The infection is

usually detected too late and the cure difficult. A

preventative spray program of Strike, Systhane,Terraguard, or others in the beginning, in the

middle, and at the end of October is

recommended.

5. The last three to four weeks of finishing beforeshipping

Shade three to four weeks before finishing ifhot and bright. Bracts tend to get droopy, thedark leaf pink varieties can get muddy, and the

dark leaf white varieties can get creamy under hot

and sunny conditions, which happens quite a lot in

the southern states.

You can stop the growth now. Bonzi drenches at - 1 ppm can be done one to four weeks before

shipping in the south and at - ppm one tothree weeks before shipping in the north. The crop

will not grow more than an inch and the bracts

will not be significantly smaller. As additional

benefits, the bracts will be tighter and less droopy,the cyathia will stay longer, and the color will be

more intense and will fade less.

Avoid producing soft growth. Bracts that aregrown too warm and with high humidity are lushand are more prone to shipping related problems.

Reduce salts and fertilizer continuously. Manyproblems, like root loss and bract edge burn at

both the grower and consumer level can be

avoided by simply leaching out the salts and by

reducing the feed down to 80 ppm N. Fertilization

should not be completely discontinued as this can

result in yellowing of the foliage with possibleleaf drop.

Leach heavily with clean water two timesbefore shipping. Add Subdue the last time. Asmany poinsettias completely dry out at the

consumer and retail level (or drown if there are

no drain holes and saucers), they can rebound

easier if there is almost no salts in the soil. Byapplying Subdue, the customers will be more

successful with their poinsettias.

Keep the air dry, circulating, and watch theroots. Many poinsettias get ruined in the lastweeks of the crop. As the weather conditions are

usually deteriorating, the plants at the same time

get more crowded and also more sensitive towardsBotrytis, Pythium, andRhizoctonia. Keeping the

humidity below 75 %, by heating and venting if

necessary, and the air moving is extremelyimportant. Night temperatures of 66

oF are ideal.

A drench with fungicides against Pythium and

Rhizoctonia is usually necessary.

6. Shipping Avoid the poinsettias being sleeved for longer

than two days .Botrytis, leafyellowing , leaf

drop, and claims increase exponentially with

every hour. Ship at temperatures of 58 62 degrees.

Temperatures below 56oF can result in bract

damage.

avoid common mistakes in poinsettia production.pdf

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