Transplant Production

General Info Most common size is 35 ft. X 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 a 30’X 245’ Greenhouse cell Trays

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 – 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 trays

Fertility Water soluble fertilizer added to water –3-1-3, 2-1-2, analysis 150 ppm N added 10 days to 2 weeks after seeding 100 ppm N 4 weeks later Or maintain ppm N with Injector

Fertilizer Effects on Water pH Well water ranges from pH , , and 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 MgSO 4 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

Effect of Temperature on Germination of K 326

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 Variety68/8668/95 -Days to Max. Germ.- K K NC NC

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

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

Effect of Pellet and Variety on the Incidence of Spiral Roots, VPI-2001

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 inches above bud Clip every 3-5 days No closer than 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 ) 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 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 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 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.