Generally, the warm-season crops such as muskmelon, pepper, tomato etc. are established from transplants to decrease the time to maturity in the field. Direct-seeding of vegetables such as sweet corn, cucumber, and snap bean through plastic allows for optimum soil temperature and moisture to insure maximum seed germination and subsequent seedling emergence. Mechanization of transplanting or seeding of vegetables in plasticulture is available and successful if a firm, flat bed with plastic film firmly stretched over the formed bed and specific crop requirements are followed during establishment
Most common mistakes made during plant establishment in plasticulture.
- Lack of a firm, uniformly level bed can lead to air pockets between soil and plastic mulch. If air flows underneath mulch, the hot air funneling through the perforated holes of the plastic mulch can result in stem damage to plants. Producing a firm, level, continuous bed will prevent this problem.
- Loose plastic over the raised bed can result in plant desiccation or death when the transplant is covered with the loose plastic mulch. In addition, high winds have the potential to lift the plastic mulch off the beds. Adjusting the plastic mulch applicator to place the mulch film tight over the beds prior to laying film in the field will prevent this problem.
- Poorly placed drip irrigation tape in the raised bed can result in non-uniform soil moisture levels and nutrient application. If the drip tape is not placed beneath the soil surface in a perfectly straight line, it is difficult to transplant without puncturing the drip tape. Use of drip tape applicator with a hollow chisel placed at a 2 to 3 inch depth in the bed will prevent this problem.
- Failure to operate the drip irrigation system immediately after transplanting; especially if soil moisture is less than sixty percent of capacity will result in poor establishment or desiccation of the transplants. Drip irrigation systems should be hooked up and operated before transplanting to prevent this problem. In addition, as plants increase in size with time, use of soil moisture sensing probes such as irrometers or tensiometers will help maintain optimum soil moisture and help determine when and how long drip irrigation systems should be turned on and off.
- Failure to remove floating row cover or plastic tunnel from a developing crop can result in plant damage or death from excessive heat. Placement of thermometers coupled with frequent reading and recording of air temperatures under row cover or tunnels in several locations will help prevent this problem.
- Either failure to calibrate the fertilizer injector or to calculate correctly fertilizer rates can result in early seedling/plant damage from excessive salt levels. Calibrate fertilizer injector with known concentrations of NPK prior to transplanting to verify correct operation of the injector. In addition, calculation of fertilizer concentrations should be reviewed by cooperative extension agent or irrigation company representatives to prevent this problem.
- Failure to remove floating row cover or plastic tunnel from a cucurbit crop during flower anthesis will result in poor fruit pollination. Monitoring field of cucurbit crop for flower development at least once a week will help prevent this problem.