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Department of Horticultural Science

Horticulture Information Leaflet 506

12/98

GUIDE TO SUCCESSFUL OUTDOOR

GARDEN MUM PRODUCTIONBrian E. Whipker and Raymond A. Cloyd1

Garden mums are a traditional fall cropand are fairly easy to grow. They alsocan be profitable. Below are some ofthe cultural guidelines to follow ingrowing garden mums.

Keys to Success with Garden Mums1. Inspect and plant cuttings uponarrival.

2. Provide sufficient water.

3. Manage your fertility program.4. Use a well-drained medium.

5. Space plants for proper growth andgood air circulation.6. Select proper cultivars.

7. Calculate your production cost.Planting

Inspect and plant the cuttingsimmediately upon arrival. Planting depthis very important. Do not plant them toodeeply. The roots should be barelycovered by the medium. Water the plantsin immediately with a complete N-P-Kfertilizer solution at the rate of 200 to250 ppm N. The plants may need to bemisted or syringed 4 or 5 times a dayduring the first few days after potting.Do not allow the plants to wilt or plantquality will be adversely affected, i.e.,retardation of growth and the potentialbranching will be reduced.

If your cuttings have set a terminal bud,they will still produce a nice plant.Allow the plants to become established

for 3 to 5 days and then give them a hardpinch. If the cuttings can not be plantedand must be held, they can be stored for

several days in a cooler at 33 to 40 F. Containers

To help care for the new cuttings prior totheir establishment, many growers plantcuttings into 36 to 72 unit cell packs (ie.:1203s or 1204s). After 2 to 3 weeks ofgrowth and the initial pinch has beendone, the plants are transplanted into thefinal container. Typically, one plant isplaced in each container. The size of thefinal container used varies with thegrower and their market. The mostcommon pot size used is an 8-inch mumpan.

Spacing

Use 18-inch to 24-inch centers for aneight-inch pot, with less space requiredfor later potted plants.

Varieties

Mums come in a wide assortment ofcolors and flower forms. Yellow is themost popular color of fall garden mums,representing 26% of the market (Yoder,1996). Pink/lavender is the next mostpopular color (22%), followed by white,bronze, and red (14% each), coral/salmon (6%), and orange (4%). Yoder’stop 10 mum varieties are (listed in order):Bravo, Jessica, Debonair, Linda, Raquel,Nicole, Sundoro, Lisa, Anna, and Yellow

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North Carolina State University,

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Triumph. Match your cultivars with the colorspopular in your market and the length of your marketingseason.

Pinching

Rooted cuttings are pinched 7 to 14 days afterpotting. Timing of the pinch varies with plantgrowth. Pinching should occur after the plants havebecome established and actively growing (ie.: 1 to11/2 inches of new top growth has developed and theroots are visible at the side of the tray pack). Removearound 1/2 inch of growth. A second and third pinchmay be required on the plants. Second and thirdpinches should be done after 3 to 4 inches of newgrowth has developed on the breaks, removing around1/2 inch of growth. Generally in the Southeast, the lastpinch date should be between July 10 and July 25 andup to a week earlier in the northern US. Pinching toolate will delay flowering. An alternative to thesecond and third pinches is covered below underFlorel.

Florel as a Pinching Agent

The requirement of pinching garden mums for thesecond and third times is very labor intensive and

costly. A relatively new production practice adoptedby a number of growers is to replace these subsequentpinches with an application of Florel. Research byWhipker (1996) compared the economics of Floreland a second pinch (Table 1). The use of Florelresulted in labor savings of almost 3¢ per plant, ora $294 savings per 10,000 mums.

Florel is a liquid formulation of ethephon (an ethyleneproducer) and acts as a plant growth regulator by:•Stimulating lateral branching•Controlling stem elongation

•Encouraging vegetative growth while controllingflowering. A rate of 500 ppm is commonly used as a substitutefor the second pinch, which occurs roughly 30 to 40days after potting. Research at North Carolina StateUniversity by Larson and McCall (1995) found thata single application of Florel at 500 ppm producedgood quality plants that were comparable to plantsmanually pinched a second time. Florel treatedplants had a slight delay in the appearance of budscompared to the manually pinched plants, but thedifference was not noticeable at the conclusion of the

application of Florel.Labor and ChemicalsPinch #1Pinching OptionPinch #2B-Nine

B-Nine Application LaborFlorel OptionFlorel

Florel Application Labor TOTAL Difference 30,000 Mums50,000 Mums70,000 Mums$0.0028$0.0070$0.0040$0.0022$0.0040$0.0200Florel Cost Per Pot$0.0294$882$1,470$2,058

$0.0028$0.0306$0.0120$0.0040$0.04942nd Pinch

Total Savings with Large Numberof Pots Produced

experiment. Florel causes flower bud abortion,and the final application should be at least 6 to 7weeks prior to the scheduled flowering date toavoid delay of floweringplant growth regulator by controlling plant height.Adjust your use of plant growth regulators like B-Nine as needed.

Some growers apply multiple applications of Florelto delay flowering and produce a larger plant, hencespreading out their marketing season for gardenmums. Discuss this option with your plant broker todetermine a production schedule that is suitable foryour operation.

Plant Growth Regulators

Plant growth varies with the cultivars and some canget too tall and require the application of a plantgrowth regulator. Growers will require at least aminimal amount of growth regulator. A plant growthregulator should be applied after the final pinch, when 11/2 inches to 2 1/2 inches of new growth hasoccurred. This will reduce plant height, intensify thedark green color of the foliage, and most importantlycreate rounder, more uniform plants. Yoderrecommends foliar sprays of B-Nine at 2500 ppm,starting around 2 weeks after the last pinch.Additional applications at the same rate can be usedif the plants begin to stretch. Do Not apply after budsare visible or a reduction in flower diameter ispossible.

Sumagic is a very active chemical. Growers need toexperiment with a small amount of their crop to testthe effectiveness and determine optimal rates.Cultivar response will vary. The label rate forSumagic is 2.5 to 10 ppm, with lower rates suggestedfor cool growing climates. Start with the lowerrange of suggested rates.

Whether using B-Nine or Sumagic, remember toreduce the plant growth regulator rate if you areapplying Florel.

Fertilization and Irrigation

Maintain root medium pH between 5.8 to 6.2 forsoilless media and 6.0 to 6.5 for soil based media.Use a complete N-P-K fertilizer such as Excel 15-5-15 Cal-Mag or 20-10-20 (with supplemental

calcium, magnesium, and mirconutrients beingapplied) at the rate of 200 to 250 ppm N and Kapplied in the irrigation water. Use a fertilizer thatprovides 60 to 75% of the nitrogen in the nitrate(NO3-N) form. Slightly lower fertilization rates maybe sufficient for a soil-based medium, while slightlyhigher rates are suggested for a bark-based mix.Growers need to manage their fertility program toavoid excessive electrical conductivity (EC) buildupor leach salts every month. Research by Larson andMcCall (1995) at North Carolina State Universityfound that higher fertilization rates of 500 ppm N didnot provide any additional benefit when compared to300 ppm N.

Table 2. Guidelines for foliar analysis values(based on dry weights) for mums.Nutrient Recommended Concentration N (%)4.00 to 6.50P (%)0.25 to 1.00K (%)3.50 to 6.50Ca (%)0.50 to 2.00Mg (%)0.30 to 0.60B (ppm)25 to 100Cu (ppm)5 to 50Fe (ppm)50 to 300Mn (ppm)30 to 350Zn (ppm)

15 to 50

Foliage of plants was sampled prior to or at flowering.Samples taken from the top-most, fully expandedleavesand are only guidelines.

Source: Plant Analysis Handbook for Georgia, 1988.

Table 3. Element deficiency symptoms.

Nitrogen Reduction in plant vigor and small, light(N)

green to yellowish foliage. In severecases, lower leaves are chlorotic andhave reddish veins and margins.Growth and flower size are reducedand flowering date is delayed.

Phosphorus Lower leaves turn reddish to yellow to(P)

brown beginning at the leaf apex. Leafsize of newly developed leaves isreduced and lower stem portions maydevelop a deep purple color.

Potassium Lack of plant vigor, small leaves and(K)

weak stems with first appearance onlower leaves.

(continued on the next page)

Table 3. Element deficiency symptoms.(continued)

Potassium In severe cases, leaves develop(K)

interveinal and marginal chlorosiscontinued

followed by necrosis.

Calcium Small, curled, thickened leaves around(Ca)

growing point. In severe cases, deathof growing point and rosetting ofleaves. Peduncles break over abouttime flower color shows and flowershave poor keeping quality. Stubby andbrown roots.

Magnesium Appears first as interveinal chlorosis(Mg)

and curling under of older leaves.Veins remain green. Severe caseshave reddish colored spots

interveinally and along leaf margins,gradually moving to upper leaves.Boron Red pigment in veins with interveinal(B)

chlorosis. Corky veins and sides ofpetioles with brittle, downward-cuppedleaves. Terminal bud may die or

secondary flower buds fail to developnormally. Larger flowers do not openfully and are more incurved thannormal. Roots brown and stubby.Copper Dull green leaves, chlorotic veins.(Cu)

Veinal chlorosis produces inverse“netting.” Margins remain green.Affected leaves wilt during day, outermargins turning upward. Flowers aresmall, reflex, and soft.

Iron Interveinal chlorosis of young leaves(Fe)

becoming a general chlorosis in leavesseverely affected. A common

deficiency at high root medium pHs.Manganese Generally pale green plants with mild(Mn)

interveinal chlorosis of young leavesnot as distinctly outlined as in irondeficiency. Severe cases with smallnecrotic spots in middle leaves,affecting up to 1/4 of the surface.Interveinal, first white or gray, thentan.

Zinc (Z)

A rarely seen deficiency. Appears asplant approaches blooming stage.

Small chloritic spots at any position onmiddle or upper leaves. Chlorotic spotsgradually develop necrotic spots in thecenter.

Source: Raulston, J.C., W.E. Waters, S.S. Woltz, and C.M. Geraldson. 1972.Summary of chrysanthemum fertilization programs for field production inFlorida. Florida Flower Grower 9 (10), p. 9.

Inducing Flowers

Garden mums are photoperiodic plants. Which meansthe length of day (or more correctly, length of darkness)influences the flowering pattern of the plant. Thecritical night length to cause garden mums to initiateflowers is between 9.5 to 10 .5 hours (Pertuit, 1996).Most cultivars on the market will naturally flowerduring September 10 to October 10. Consult yourcutting supplier for establishing a schedule that meetsyour market demands.

Growers can also extend their marketing season byshading plants to induce earlier flowering. A shadingsystem utilizing black cloth or black plastic is usedduring the approximately seven weeks required toinduce flowering. The shading system is pulled overthe plants at dusk to limit heat buildup under the clothand removed early in the morning. This provides atleast 11 to 12 hours of darkness. High averagetemperatures can cause heat delay, with floweringpotentially being delayed 1 to 3 weeks. The shade clothis not used on evenings when heavy rainfall is expecteddue to water pooling on the cloth. A sample schedulefor shading plants is given in Table 4.

Scheduling/Timing

An example schedule is given for producing a naturalseason garden mum, Table 5. This is a basis forplanning your schedule, but variations will occur dueto variety selection, environmental conditions, andfertility programs. Consult your cutting supplier forsetting up a customized schedule for your operation.Cost of Production

Profitable production of garden mums is dependentupon the knowledge and control of production costs. Agrower who understands production costs will bebetter prepared to make decisions on the optimalnumber of plants to produce and to help establishprices. The costs presented here should be useful tocurrent growers who wish to compare their ownproduction expenses and for potential growers indetermining whether to begin growing garden mums.The data was collected from a Midwestern grower whoproduced 70,000 garden mums. Costs are calculatedfor the 1996 growing year, Table 6.

Costs: variable versus fixed. Costs can be categorizedas either variable or fixed. Variable costs, also called

Table 4. Early shaded garden mum timetable - 1997 (6" or 6-½” pots - one cutting per pot).Plant Apr. 28May 05May 12May 19May 26June 02June 09

Approximate First PinchMay 12May 9May 26June 02June 09June 16June 23

Approximate Second PinchJune 02June 09June 16June 23June 30July 07July 14

Shade June 02June 09June 16June 23June 30July 07July 14

Flower 7 Weeks July 21July 28Aug. 04Aug. 11Aug. 18Aug. 25Sep. 01

Based on starting with a rooted cutting. Long days provided until the shade date. Source: Yoder’s 1996-1997 Garden Mums Guide.

Table 5. Example production schedule for natural season garden mums.Date May 20June 3June 17July 1July 15July 29

Mid-September to mid-October

Second Pinch SchedulePot Pinch 1Pinch 2

B-Nine Application1B-Nine Application3B-Nine Application3Flowering 4

Florel SchedulePot Pinch 1

Florel Application 2B-Nine ApplicationFlowering 4

B-Nine applied after the last pinch when 1½ to 2½ inches of the growth has occurred.Additiona application used only ifneeded. 2

Florel applied as a substitute for a second pinch at 500 ppm.3

B-Nine application only required if excessive growth has occurred.4

direct costs, are costs that are incurred directly bygrowing the crop. Variable costs items are the basicinputs required to grow a crop, such as pots, plants,media, or chemicals. These items’ costs are fairlyeasy to allocate to a specific crop because you knowthe materials used to produce the crop and productionpractices you followed. The direct costs are $0.98per pot.

Fixed costs, also called overhead or indirect costs,are incurred whether or not a crop is produced. Theyinclude items like management salaries, depreciation,insurance, interest, repairs, and taxes. Fixed costs

represent general operation expenses present in everygreenhouse facility. To get a good measure ofprofitability, these costs need to be allocated to eachcrop grown. In general, for greenhouse operations,fixed costs are allocated to a crop on a cost-per-ft2-per-week basis. Because garden mums are grownoutdoors, fixed costs were allocated to the mum cropon a percentage basis, based on: the actual use of apiece of equipment or as a percentage of sales. Theremaining percentage not allocated to the mum cropwould then be allocated to the other crops producedlike bedding plants or poinsettias.

Fixed costs are only $0.05 per pot.The fairly lowdepreciation expense can be attributed to this firm’sreliance on used equipment. Firms which purchasenew machinery and equipment will have a higherdepreciation expense.

Shrink . Even under the best production practices, acertain percentage of the crop will not be marketabledue to poor growth, insects, disease, or damage. Thecost of inputs for these non-marketable plants haveto be accounted for by the operation. This is done byadjusting the production cost by a shrink factor. Inthis case, a 3% shrink was calculated which involvedTable 6. Example production costs for naturalseason garden mums.

Cost perItem

Pot Cutting $0.2000Pot/Soil$0.2410Fertilizer $0.0200Chemicals $0.1746Sub-Total $0.635Labor

$0.3007Sub-Total Indirect Costs$0.936Interest on Direct Expenses

$0.0421(Direct expenses * 9% interest * 0.5 years)Total Direct Costs

$0.936Equipment/Interest/Repairs$0.228Overhead Operation Costs$0.2263Full-time labor

$0.2868Utilities/Taxes/Misc. Costs$0.513Sub-Total

Total Indirect Costs

$0.741Total Production Costs

$1.7203% Loss (divide T.P.C. by 0.97)$0.0532Total Costs (including shrink)$1.773Delivery Cost (Labor and Expenses)$0.30Total Costs (Delivered)$2.073

Revenue

Wholesale Price:

$2.70Non-delivered and Delivered

Total Net Profit per Pot (Wholesale) Non-Delivered$0.927 Delivered

$0.627

dividing the total production costs by 0.97 to get thetotal production costs (including shrink). Totalproduction costs will increase for growers who havea higher percent of shrink.

Total production costs per pot , including a 3%shrink and costs for marketing the crop was $2.07.Profitability . By adding the total variable costs andtotal fixed costs together, this provides the total costsof producing a crop. The profitability of the crop isdirectly related to the price received. The profitabilityper pot of a delivered garden mum was $0.627 (a23% profit margin).

Using the method outline in this handout will enablemum growers the ability to compare the profitabilityof their crops for their own operation. Of coursecosts will vary among greenhouses according totheir amount of capitalization in equipment andstructures and their ability to purchase inputs atlower costs. Therefore, each operation will need tocalculate their specific production costs in order todetermine their own profitability.

Diseases

The primary diseases of garden mums are bacterialleaf spot, Septoria leaf spot, Pythium, and Botrytis.Bacterial leaf spot is caused by Pseudomonas cichorii which is often more prevalent followingperiods of heavy summer rains. Bacterial leaf spotdevelopment is favored by moisture, high humidity,high temperatures, and/or use of susceptible cultivars.Bacterial leaf spot symptoms include dark-brown toblack spots that can cover half the leaf. These spotseventually expand to irregularly shaped lesions. Thedisease typically begins at the lower leaves and willspread upward, usually on one side of the plant.Rogue infected plants and apply Bordo-Mix 12.75WPor Kocide 101 77WP (copper hydroxide) tosusceptible cultivars.

Septoria leaf spot is caused by Septoria chrysanthemella , and symptoms include smallyellow spots that later turn dark brown to black.Later, leaves may turn yellow and drop from the plantor may remain attached to the stems. The disease isspread by splashing water, so overhead wateringshould be avoided. Cleary’s 3336, Daconil 2787

75WP, Domain, Kocide 101 77WP, or Systec 19984F are labeled for Septoria leaf spot.

Pythium is usually present in most media. Growersshould avoid growing conditions which stress theplant, such as continuously water-logged medium,high EC levels, cool medium temperatures, or coolair temperatures. If needed, monthly drenches ofAliette, Banrot, or Subdue Maxx can be applied.

Botrytis can also be a problem on leaves and flowers.Avoid overhead watering and space plants to allowfor good air circulation. Fungicides registered forcontrol of Botrytis on chrysanthemums are fludioxinil(Medallion), iprodione (Chipco 26019), mancozeb(Protect T/O), and vinclozolin (Ornalin).

Insects and Mites

Garden mums are less susceptible to insect and mitepests compared to florist mums. However, gardenmums can be attacked by a number of insect/mitepests such as aphids, caterpillars, leaf miners, spidermites, and thrips, Figure 1. Most pests can be managedwith a proper scouting program. Early pest detectioncan lead to fewer problems, especially when pest

populations are low compared to controlling highpest populations or populations that are rapidlybuilding up. In addition, early pest detection canmaximize the effectiveness of foliar-applied and/orsystemic pesticides.

Aphids . Chrysanthemum aphid, green peach aphid,and melon aphid are the common species that feed on

garden mums. Aphids feed on terminal growth, flowerbuds prior to opening, and on leaves in the plantinterior when plants are bushy. They feed on planttissue with their piercing-sucking mouthparts causingplant stunting, wilting, leaf yellowing, and leafcurling. A by-product of their feeding is a clear,sticky honeydew substance that coats plant leaves.Honeydew serves as a medium for black sooty moldfungus. The presence of black sooty mold fungus and/or aphid cast-skins can reduce crop marketability.Aphids are soft-bodied insects that have tubes(cornicles) located on their abdomens. Females cangive birth to 60 to 100 live young per day for a periodof 20 to 30 days. This ability to reproduce quicklyleads to tremendous numbers within a short period oftime.

Aphids feeding on exposed terminals or flower budsallow for better control with contact insecticides.However, aphids feeding within the plant canopy areharder to control with contact insecticides, becauseit is difficult to get thorough coverage. When gardenmums are placed outside, aphids are exposed tomany natural enemies which may provide somecontrol. For example, female parasitic wasps willlay eggs inside aphids and eventually turn aphids intogray-brown mummies.

Chemicals used for aphid control include acephate(Orthene), azadirachtin (Azatin), bifenthrin (Talstar),chlorpyrifos (Duraguard), diazinon (Knox-Out),endosulfan (Thiodan), fenpropathrin (Tame),horticultural oil (Ultra-Fine Sun Spray),imidacloprid (Marathon), insecticidal soap (M-Pede), and methiocarb (Mesurol).

Leaf Miners. Leaf miners can cause considerabledamage to garden mums if not detected early.Chrysanthemum and serpentine leaf miners are thecommon species that infest garden mums. Adultfemales puncture the leaf surface and lay eggs insidethe leaf with their ovipositor. Eggs hatch into larvaethat tunnel between the upper and lower leaf surfacescreating white blotches and/or twisting mines. Thesemines can disfigure leaves and reduce cropmarketability.

Chemicals used for leaf miner larvae control areabamectin (Avid), acephate (Orthene), azadirachtin

(Azatin), and cyromazine (Citation). Chemicals usedfor adult control are chlorpyrifos (Duraguard) andpermethrin (Astro).

Spider mites. Two-spotted spider-mite is thecommon species that can infest garden mums. Spidermites feed primarily on leaf undersides removingplant sap (chlorophyll) with their stylet-likemouthparts. Their feeding causes leaves to have a“stippled” appearance which appears on the leafupper side. Severe mite damage can cause leaf drop.Two-spotted spider mites are yellow-brown to darkgreen in color with two dark spots on both sides ofthe body. Mites are a problem under dry and warm(70 o F) weather conditions. Development from eggto adult can occur within 14 to 21 days depending ontemperature. The higher the temperature the less timeit takes to go from egg to adult.

Chemicals used for control of spider mites areabamectin (Avid), bifenthrin (Talstar), dicofol(Kelthane), fenpropathrin (Tame), horticultural oil(Ultra-Fine Sun Spray), and pyridaben (Sanmite).Thrips . Western flower thrips and flower thrips arethe two most common species that attack gardenmums. Thrips feed on leaves and flowers with theirrasping-piercing-sucking mouthparts. They causeleaves to have a silvery-appearance and they leaveblack fecal droppings. Thrips can also damageflowers by scarring the petals, deforming flowerbuds, and causing bud abortion.

Thrips are generally a problem when the crop is inthe greenhouse. Thrips are small insectsapproximately 1 to 2 mm (1/8 inch) long. Females layeggs into leaves or flower petals. When young emergefrom eggs they feed on leaves and flower buds.Thrips pupate in soil, leaf litter, and even on plants.After pupation, they emerge as winged adults. Oncethrips enter unopened flower buds they are extremelydifficult to kill with contact insecticides.

Chemicals used for thrips control include abamectin(Avid), acephate (Orthene), azadirachtin (Azatin),Beauveria bassiana (Naturalis-O/Botaniguard),chlorpyrifos (Duraguard), diazinon (Knox-Out), andfenpropathrin (Tame).

Caterpillars . Beet armyworm, cabbage looper, cornearworm, European corn borer, and fall armywormcan infest garden mums. Caterpillars can infest almostall aboveground portions of plants. They feed onleaves, stems, and flower/terminal buds. Adultfemales (moths) lay eggs on plant parts. Younglarvae emerge from eggs and begin feeding.Caterpillars consume more as they mature until theyreach the stage where they are ready to pupate andthen turn into adults. Adults generally migrate ontogarden mums when the plants are placed outside.Chemicals used for caterpillar control includeacephate (Orthene), Bacillus thuringiensis (Dipel),bifenthrin (Talstar), cyfluthrin (Decathlon),fluvalinate (Mavrik), and permethrin (Astro).When using chemicals be sure to read the label andwear appropriate protective clothing. Also, applychemicals when the environmental conditions arefavorable to avoid phytotoxicity.

For Further Reading:

•Larson, R.A. and I.F. McCall. 1995.Garden chrysanthemum culture the easyway. North Carolina Flower Growers’Bull . 40(6):1-3.

•Pertuit, A.J. Jr. 1996. Garden mums.Georgia Floriculture 6(4):14-18.

•Pundt, L. 1995. Watch for these pests ofgarden mums. Connecticut GreenhouseNewsletter , No. 185, Apr./May 1995.•Whipker, B.E. 1996. Cost of producingcontainerized garden mums: 1996. North Carolina Flower Growers’ Bull. 41(4):1-6.

•Yoder Garden Mum Cultural Manual,

1996-1997.