Transplant Production

General Info

• Most common size is 35 ft. X 100-300 ft.

• Walkway down middle

• Sectioned into 16 ft. wide beds on each side of walkway up to 100 ft long

• Beds lined with black plastic

• Filled with 3.5 – 5 inches of water

• Side-curtains, exhaust fans, heaters

Transplanted Acres and Costs from a30’X 245’ Greenhouse - 288 cell Trays

Usability (%)

Acres Planted

85 102.7

80 96.6

75 90.6

70 84.5

Water Quality

• Have water tested every year (NCDA)

• Avoid pond and river water

• Most common problems– High bicarbonates (eastern NC)

• Add sulfuric acid

– Low boron (Piedmont)• Add boron

Trays and Media

• Trays are made of polystyrene, float– 200-332 cells per tray, Most common is 288

• Filled with media– Peat, vermiculite, perlite, wetting agent, lime,

fertilizer

• 3 cubic ft. bag of media will fill 18-20 trays

Fertility

• Water soluble fertilizer added to water– 3-1-3, 2-1-2, 4-1-4 analysis

• 150 ppm N added 10 days to 2 weeks after seeding

• 100 ppm N 4 weeks later

• Or maintain 100-125 ppm N with Injector

Fertilizer Effects on Water pH

• Well water ranges from 4.5-8.5 pH

• 16-4-16, 15-5-15, and 21-5-20 are acidic and should only be used on high pH water

• pH of 4 and below can burn off roots in the float water

Fertilizer Salts Injury

• Fertilizer salts accumulate in the top of the tray as float water evaporates

• Salts can kill very small seedlings

• Waiting to add fertilizer to bed reduces loss

• Check fertilizer salts with conductivity meter

• Water overhead to lower salt level

Sulfur Deficiency

• If media not supplemented with MgSO4 or gypsum

• Most media contain sulfur and some fertilizers do

• General yellowing of plants

• Add epsom salts

Boron Deficiency

• Causes bud distortion

• If no boron in water or fertilizer

• Add Borax

• Very small amount needed, toxicity is problem

Seed Germination

• Seed no more 60 days before anticipated transplanting

• Optimum Temperatures: 70 night/85 day

• Lower Temperature only slows germination

• Higher Temperatures slow germination and can reduce total stand

Effect of Temperature on Germination of NC 71

0

10

20

30

40

50

60

Hours After Seeding

No/

50

20/30 (68/86)20/35 (68/95)30/40 (86/105)

Effect of Temperature on Germination of K 326

05

101520253035404550

Hours After Seeding

No.

/50 20/30 (68/86)

20/35 (68/95)30/40 (86/105)

Summary

• Response to 68/86 is always better than 68/95.

• Some tolerate it hot, others don’t.– Spt 168, NC 606, and NC 72 performed well at

86/105.– NC 71, NC 297, and NC 291 performed poorly

at 86/105.

Effect of Temperature on Days to Reach Maximum Germination

Variety 68/86 68/95

-Days to Max. Germ.-

K 326 7 8

K 346 7 9

NC 71 9 11

NC 297 7 9

Uniform Emergence

• Maintaining optimum temps.

• Seed by 5- day forecast for sunny days

• Uniform tray filling, growing media and seed placement

• Ants and Mice

Total and Usable Plants at Day 50

40

50

60

70

80

90

100

Per

cen

t

Ch

ec

k

75

/25

-3

75

/25

-5

50

/50

- 3

25

/75

- 3

25

X4

1-4

Treatment

TotalUsable

2000

Primed Seeds

• Seed treatment process that promotes germination

• Response is variable

• Should be a seed company decision

Spiral Roots

• First root at germination fails to go into media• Can be a few or up to 60% • Causes:

– Seed pelleting– Environment

• 50-75% will never make a usable transplant

Spiral Roots

Effect of Pellet and Variety on the Incidence of Spiral Roots,

NCSU-2001

0

5

10

15

20

25

Percent

Spt 179 Spt 168 Spt 172 Spt NF 3

Pellet APellet B

Effect of Pellet and Variety on the Incidence of Spiral Roots,

VPI-2001

0123456789

10

Percent

Spt 179 Spt 168 Spt 172 Spt NF 3

Pellet APellet B

Uniform Growth

• High quality media

• Monitor fertilizer salts

• Monitor temperatures

• Clip plants properly

• Quality water

• Manage insects and disease

Clipping

• Increases usable transplants

• Increases uniformity of transplants– Stem length and stem diameter

• Improves hardiness

• Holds plants for transplanting

• Optimum is around 5 times

• Many are clipped 20 or more times

Clipping

• Start when total plant height is 2-2.5 inches above bud

• Clip every 3-5 days

• No closer than 1-1.5 inches above the bud

• High vacuum mower

• Dump clippings 100 yards from greenhouse

Disease Management in Greenhouses

• SANITATION (before seeding)– Rinse old trays and fumigate with Methyl

Bromide– Rinse walkways and side curtains– Remove weeds in and around greenhouse

Disease Management in Greenhouses

• SANITATION – Dump clippings 100 yards away from

greenhouse– Clean mowers after clipping with 50% bleach

solution– No tobacco products in greenhouse– Clean hands shoes before entering

Common Greenhouse Diseases

• Rhizoctonia Stem Rot

• Pythium Root Rot

• Blue Mold

• Collar Rot (Sclerotinia)

• Tobacco Mosaic Virus

Carryover of Rhizoctonia on Trays

Rhizoctonia Management

• SANITATION

Pythium Damping-Off

• Roots turn light brown and groups of plants turn yellow

• Worse during cool wet conditions inside GH and when pH is high (usually above 6.0-6.2)

• Tray sanitation and high quality media are important to help prevent the disease.

• More severe with warmer float water temperature.

Pythium Root Rot in Tobacco Greenhouses

Pythium Management in Greenhouses

• Use new or sanitized trays• Keep media pH below 6.2• Float trays:

– Wash, then methyl bromide @ 3 lb/1000 cu ft for 24 hr, then aerate 24 to 48 hr.

• Thoroughly mix Terramaster 35 at 2 oz wt/100 gal of float water 2-3 weeks after seedling.

Blue Mold on SeedlingsBlue Mold on Seedlings

Blue Mold Prevention in Greenhouses

• Grow your own plants from seed.• Apply Dithane DF at ½ lb per 100 gal spray

– Every 7 to 10 days from quarter size to transplanting

– 6 to 12 gal water per 1000 sq ft depending on plant size

• Destroy all plants in a greenhouse if blue mold is found and plants had not been treated.

Sclerotinia Ascocarps Outside Greenhouse

Collar Rot Management

• Seed ONLY 55-60 days ahead

• Use good ventilation and circulation

• Dump clippings, dead plants, and media at least 100 yards from greenhouse

• Plant vegetable gardens at least 100 yards from greenhouse

TMV

Mosaic

(NC 297) Local Lesions

Mosaic Prevention in Greenhouses

• Thoroughly clean mower and sanitize with 50% clorox. Sanitize between clipping beds.

• Use 10% clorox to wash side curtains.• Avoid excessive clipping.

– Clip no more than 10 times

– Keep temperatures cooler and don’t over fertilize

• Do not allow the plants to be touched until transplanting.

Mosaic Prevention (cont.)

• Do not allow users of tobacco products in the greenhouse.

• Carefully check plants for tmv before transplanting.

• Do not allow weeds to grow in the greenhouse, especially horsenettle or nightshades.