Detailed Explanation of Carnation Seedling Cultivation Methods and Technical Key Points

Propagation Methods For carnation cut flower production, seedlings can be propagated by cuttings, layering, tissue culture, and other methods, usually with cuttings as the main method.

Cuttings can be taken at any time except in the heat of summer, but in production it is best to do so from January to March, especially from late January to early February, when the results are best and the survival rate is highest. Morning, evening, or cloudy days are best for taking cuttings. Through cultivar cultivation trials, select lateral buds (i.e., the 3rd and 4th buds) from robust, high-quality mother plants as cuttings. Take them when the terminal bud is 1 cm in diameter, pulling downward along the stem so that the cutting has a heel portion, which makes it easier to root and avoids wounds made by a knife that can carry bacteria. Alternatively, after the main and lateral stems of the mother plant have grown to 5-6 nodes, cuttings can be taken in combination with pinching. The cuttings should retain 4-5 pairs of leaves and a complete stem tip to facilitate photosynthesis and the production of auxins and other nutrients. The cuttings are 12-14 cm long, and the waxy protective tissue on the leaf surface has formed well. Before cuttings are taken, prepare an appropriate amount of rooting powder. Dip the base of the cutting shoot about 6 mm deep into the rooting powder, then insert the cuttings separately into the substrate, one bud node per hole, generally 2-3 cm deep. After taking the cuttings, insert them immediately or organize them into bundles of 20 or 30 stems, soak them in clean water for 30 min to allow them to absorb enough water before inserting. Never allow the stems to wilt, as this affects the survival rate. The cutting medium can be 1/2 peat plus 1/2 perlite, or sandy soil. The cutting spacing is 2-5 cm. After insertion, water promptly and provide shade to prevent water transpiration and loss of soil moisture. The room temperature should be controlled at 10-13°C, and healing and rooting take about 20 days. (Note the watering tools must be thoroughly cleaned before use.)

The temperature of the seedling room should preferably be controlled at 21-24°C. If this temperature is exceeded, the seedlings grow weak and spindly, which is unfavorable for transplanting and field planting. If it is below 20°C, the seedlings are prone to stalling or root development is hindered, and the roots produced are prone to rotting due to excessive humidity. Under suitable temperature and humidity conditions, seedlings can be ready in 22 days. During the seedling period, 75% mancozeb 500x solution and 50% diazinon 800x solution should also be used as protective sprays to prevent pests and diseases. One day before transplanting, the seedlings together with the cutting substrate around the roots should be lifted and placed into large-mouth plastic bags equal in height to the seedlings, placed in a single layer in perforated cardboard boxes, with 25 seedlings per plastic bag and 10 bags per box.

Labels with the cultivar and cutting date should be affixed to the outside of the boxes, and the seedlings should be placed in the planting greenhouse for one night of hardening off. When moved into the planting greenhouse, sufficient water should be sprayed to prevent drying out. If diseased plants are found when lifting the seedlings, they should be taken out of the greenhouse and buried deeply or burned. Seedlings must not be pulled up by hand.

At present, viral diseases of carnations are becoming increasingly serious. To obtain virus-free seedlings and accelerate propagation speed, tissue culture is widely used. The method is to disinfect the explants according to routine procedures, cut 0.2-0.5 mm stem tips in a sterile operating room, inoculate them onto the culture medium, and after about 2 months of culture, virus-free seedlings can be grown.

Cultivation Management In hot summer regions, one-year cultivation is mostly used, that is, planting in early summer and ending in early summer of the following year.

1. Land Preparation and Fertilization Choose sandy loam with good aeration in the topsoil and good structure as the cultivation site. Apply base fertilizer before land preparation, mainly peat or farmyard manure. After deep plowing and leveling, make beds. The bed surface width is 1.1 m, and a 0.6 m wide path is left between two beds for easy management. If there are pathogenic bacteria in the soil harmful to carnation growth, soil disinfection must be carried out before planting.

2. Planting The time required from field planting of carnations to flowering is generally about 4-5 months, and the planting time can be appropriately adjusted according to market flower supply demand. Generally, after cuttings are rooted and emerge, if transplanted in March, planted in the field in May, they bloom in mid-to-late September. The planting spacing is 15 cm x 15 cm, about 45 plants per sq m. Calculated at 6-7 stems of flowers per plant, the yield is 60,000-100,000 stems of flowers per mu. During planting, the soil must remain moist, and planting should be as shallow as possible. After planting, the original rooting medium of the cuttings may be slightly exposed above the soil surface. Keep the seedlings upright and strong, with neat planting positions, and do not knock off the root soil carried by the seedlings. After field planting, a furrow should be made beside each plant and watered thoroughly. Before the plants show obvious growth, the entire seedbed should not be fully wetted, to avoid root rot causing damping-off. After summer planting, water lightly within 7-10 days, until the plants clearly grow new shoots.

3. Post-Planting Management After field planting, to prevent seedlings from lodging, support netting should be put up promptly. The grid size should match the planting spacing of the seedlings. The first layer of netting is 15 cm above the ground, and the spacing between layers is about 20 cm. A total of 4-5 layers can be set up so that each plant is within a suitable grid and does not lodge. When the plants grow to 7 cm tall, pinching can be carried out to encourage more branching and form a bushy plant. When pinching, remove the center and the 2 leaves above it, retaining 5-6 pairs of leaves. This can be repeated multiple times to make the plants form a clump, until pinching stops in July. Generally, it takes 5-6 months from pinching to flowering, and this can be used to stagger the flowering period. In addition to pinching, timely bud removal and disbudding are also needed. Except for branches intentionally retained, all other lateral buds and upper lateral buds should be removed to ensure that nutrients are concentrated in supplying the main stem and main bud. During the seedling stage, alternate wet and dry conditions are needed. After intertillage and seedling recovery, 2-3 moderate "seedling hardening" treatments should be carried out to encourage the plant roots to develop deeper into the soil. Throughout the entire growth period, there must be a sufficient supply of fertilizer, applying light fertilizer frequently. After field planting, topdress once every 10-15 days. In the peak growth periods of August-September and April-May, fertilize frequently, once every 5-7 days. In summer, moderately lower the temperature. Shade netting can be used to provide shade and avoid direct sunlight, or spraying can be combined to provide a good artificial microclimate; otherwise, excessively high temperatures will cause carnations to show narrow leaves, small flowers, and poor branching. In winter, attention should be paid to insulation and ventilation.