1、Seedless Watermelon Transplant Production Guidelines,Dr. Richard L. Hassell Clemson University Coastal Research and Education Center Charleston, South Carolina Rhasselclemson.edu,Dr. Jonathan R. Schultheis North Carolina State University Department of Horticultural Science Raleigh, North Carolina jo
2、nathan_schultheisncsu.edu,Table of Contents,Introduction Seed Trays Soil Mixes Tray Preparation Seeding Germination Chambers Greenhouse Growing,Introduction,Triploid (seedless) watermelon seed have more exact growing requirements than diploid (seeded) watermelonFailure to provide optimum growing pra
3、cticescan result in:reduced seed germinationuneven seed germination and transplant sizeleggy/elongated transplantsweaker plants resulting in yield reduction,Transplant production requirements are more precise with seedless watermelons than seeded watermelons. Note the reduced plant emergence and var
4、iable plant size in the transplant tray with a seedless variety (right) compared with the more complete uniform plant size in the transplant tray with a seeded variety (left) 5 days after sowing.,Diploid or seeded cultivar,Triploid or seedless cultivar,Seed Trays,Choose trays that fit your particula
5、r set up andare economically feasible for your operationUse square cells when ever possibleMake sure cell depth is at least 2”Remember, the smaller the cell diameter, the more attention to plant production is needed! Timely response to plant need is critical!,Choose trays that fit your particular se
6、t upand are economically feasible for your operation,Styrofoam “Speedling” grow tray - clean and re-use,No. 242 cell trayTray Dimensions: 13.5” x 26.5”Cell Dimensions: 2” Deep 1” square,Styrofoam “Speedling” grow trays for re-use,Regardless of tray type, it is critical that the tray is disinfected/
7、treated with chlorox,Rigid plastic tray suitable for re-use after sterilization,Re-usable Plastic TrayTray Dimensions: 13.5” x 26.5”Cell Dimensions: 2” Deep 1.25” square,TLC #128 trayTray Dimensions: 11” x 21.5”Cell Dimensions 2” Depth 1.19” Square,Use square cells when ever possible,Round cells cau
8、se root girdling,Remember, the smaller the cell diameter, the more attention to overall plant needs must be considered!,#288 Tray - Tray dimension 11” x 21.5” cell size -1.5” deep X .81” square,Soil Mixes,Choose as coarse a mix as possible for the tray chosen. (Examples are: Metro-Mix 300, Fafard Pr
9、ofessional No 2, Pro-Mix BX)Do not use a plug mix! -Plug mixes are too fine. -A fine mix makes it easy to over water making less oxygen available to the roots,Soil mixes come in all makes and sizes,Soil mix ingredients may vary greatly in their content,Tray Preparation,1. Fill trays 24 hours before
10、seeding.2. Wet trays to field capacity.3. Let trays stand 24 hours before seeding to drain excess water.4. If warm water is not available, place trays in area where temperatures of the mix are at least 850F before seeding.,Fill trays 24 hours before seeding,Wet trays to field capacity and let stand
11、24 hoursbefore seeding to drain excess water,If warm water is not available, place trays in area where soil mix temperature reaches at least 850F before seeding,Seeding,1. Place seeds at least one inch deep, preferably with the radicle end pointed up.2. Cover tray with warm, moist mix or pinch thear
12、ea closed around the seed.3. DO NOT ADD WATER TO THE MOISTENED MIX!4. Place trays back in the warm germination room ASAP!,Seeding,5. Stacking trays OK as long as air movementaround trays is provided.6. Remove trays after 48 hours (NOT 49!) - seed examination not necessary. (more than 48 hours will c
13、ause excessive hypocotyl growth).*If seedlings have visibly started to emerge youre too late!,Seeding,Seeders vary in shape, size, and capabilities,Place seeds at least one inch deep,Radicle end pointed up if possible,Cover tray with warm, moist mix or pinch thearea closed around the seed,DO NOT ADD
14、 WATER TO THE MOISTENED MIX AFTER SEEDING!,Place seeded trays back in the warm germination roomStacking trays is permissible with air movement around them,Air circulation,Air circulation,Germination Chambers,No single perfect designTemperature and humidity controlMoisture is maintained by a fog syst
15、emShelves to place the traysBest temperature control is by hot water pipes along baseboards,“Home-made” germination chamber,Temperature Controls,Insulated Sidewalls,Commercial vegetable cooler converted to germ room,Heater and controls,Uniform humidity controls is a must no matter what the size of c
16、hamber chosen!,Germination Conditions,Seed Germination Takes Place In Two Stages A. When The Root Emerges (Germ Rooms Only) B. When The Hook Appears (Greenhouse Only)Uniform Soil Temperature In Germ Room Must Be Maintained A. Seedless Need 850F,Germination Conditions,Germination Dependent On Moistur
17、e A. Too Much Inhibits Oxygen B. Too Little Prevents Seed SwellApply A Cover Of Vermiculite, Plug Media, Sand, Perlite,Excellent seed germination after 48 hours in the germination room at 85oF,Seed germination beyond 48 hours at 85oF to 90oF,Root elongation and initiation of root hairs,Seedling emer
18、ging through soil mix,Greenhouse Growing,1. After 48 hours, move trays to the greenhouse.2. Temperatures.-Set night temperature at 650F.-Cooling set to come on at 70-750F.-Too warm setting will cause hypocotyl stretching.3. Do not water until signs of seed emergence appear.- Excess water will also c
19、ause hypocotyl stretching.,Greenhouse,4. Do not fertilize before appearance of first true leaf.(NOT the cotyledon leaf!)5. At first true leaf - begin fertilization with a continuous feed of 50 ppm N or a 100 ppmtwice per month.6. Slow growing = quality transplants!7. Four to six weeks needed from se
20、eding to transplant.,Remove trays from germ room after 48 hours to the greenhouse!,Greenhouse Temperatures1. Set night temperature at 650F.2. Cooling set to come on at 70-750F.3.Too warm setting will cause hypocotyl stretching,DO NOT ADD WATER TO THE MOISTENED MIX UNTIL THE SEEDS HAVE FULLY EMERGED!
21、,If seedlings have started to emerge in the germ room youre too late!,Hypocotyl extension,Do not water until signs of seed emergence appear!,Seed coat adherence caused by: Seed orientationToo fine a mix,Excess water and high temperatures in the greenhousewill also cause hypocotyl stretching!,Seedlin
22、gs showing elongated hypocotyl growth caused by:1. Over-watering 2. Temperatures above75oF.,Seedlings showing short hypocotyl growth caused by:1. Controlled watering 2. Temperatures at 75oFor below.,Do not fertilize before appearance of first true leaf.,NOT the cotyledon leaf!,First true leaf.,At first true leaf - maintain fertilization with a continuous feed of 25 ppm N or 100 ppm twice per month,Well formed root systems of watermelon transplants.,Slow growing = quality transplants! Four to six weeks to quality transplants!,GOOD GROWING!,
