Greenhouse production of perennial flowers: these few experiences are worth learning from

When producing perennial flowers in a greenhouse, scientific management is necessary in order to achieve high quality and high yield, year-round supply and lower costs. A few specific experiences are introduced below.

Potting up

In choosing flower pots, follow the principle of small pots for small seedlings and large pots for large seedlings. New flower pots need to be soaked in water for 1 to 2 days before use to remove the residual heat and alkali, preventing the pot wall from absorbing water strongly and damaging the flower roots. Old flower pots must be scraped and washed clean, removing soil and moss from the pot wall to facilitate air permeability and water seepage. The potting-up method is: choose a suitable flower pot and cover the drainage hole at the bottom of the pot with a tile or plastic window screen. Then fill the bottom of the pot with about 3 cm of growing medium, place the plant in the center of the pot, and fill growing medium around the root system until the roots are completely covered. Lift the plant gently so the roots spread out, press the growing medium lightly at the base with your hand so the soil particles make close contact with the roots, then add more growing medium until it is 3 cm below the pot rim. The first watering after potting up is called "settling water"; it should be thorough and complete to help the flowers survive.

Repotting

After seedlings are potted up, as the branches and leaves grow, they usually need to be repotted several times before flowering. Stop watering before repotting so the potting soil reaches a certain degree of dryness. Then tip the flower pot over, tap the pot wall lightly, and insert your fingers into the drainage hole to push out the potting soil, taking the plant out of the pot with soil around its roots. Cut off old roots and rotten roots, and plant the plant again in a new, larger flower pot. The recovery period is about 4 to 5 days.

Turning the pots

Because sunlight in a greenhouse mostly enters only from the south side, if perennial flowers are kept in a fixed position inside for a long time, they will develop a lopsided crown due to phototropism. For this reason, the pots should be turned regularly and at the right time, once a week during the vigorous growth period.

Rotating the pots

The purpose of rotating the pots is to make the plants grow evenly; in different positions in the greenhouse, light, temperature, humidity, ventilation and so on all differ to some extent. The flower pots should be swapped at the right time.

Watering

Choose water of good quality that is slightly acidic to neutral. The water temperature should match the temperature of the plant's growing environment; do not directly water with water that is too cold. Well water or tap water should be placed in a storage tank for 1 to 2 days before use. The amount of water applied depends on the species of perennial flower, the growth and development stage and the change of season. For example, flowers that are xerophytic, in the dormant period or in a slow-growth period need relatively less water, while wetland plants or flowers in the vigorous growth period need relatively more water. In spring, when temperatures rise, it is windy and the relative air humidity is low, increase the amount of watering, once every 1 to 2 days; in summer, when temperatures are high and evaporation is great, also increase the frequency of watering, once in the morning and once in the evening, and if wilting is seen, one supplementary watering can be given at noon; in autumn, as temperatures gradually fall and plants grow slowly, this can be reduced to once every 2 to 3 days; in winter, the water needs of different flower species differ greatly, so they must be treated differently. Those overwintering in a cold room can be watered once every 5 to 10 days; those grown in a greenhouse need watering once a day or every other day.

Fertilizing

For base fertilizer, organic fertilizers such as livestock and poultry manure are mostly chosen, mixed with part of the phosphorus and potassium fertilizers. Potted flowers have a limited amount of potting soil, so the nutrients the plants need must also be supplemented by topdressing. To prevent the fertilizer from fermenting and generating heat that harms the roots, cake fertilizer, livestock and poultry manure and the like are mostly fermented and then applied as liquid fertilizer. For alkaline soil, acidic fertilizers should be chosen, for example nitrogen fertilizer can use ammoniacal nitrogen (ammonium sulfate, ammonium chloride); phosphorus fertilizer can choose water-soluble fertilizers such as calcium phosphate or ammonium phosphate. For acidic soil, alkaline fertilizers can be chosen; nitrogen fertilizer can use nitrate nitrogen; phosphorus and potassium fertilizers can use phosphate rock powder, plant ash and so on.

Topdressing

When starting topdressing, the liquid fertilizer should be dilute rather than concentrated, generally once every half month. During the vigorous growth period it can be once every 5 to 7 days, and the concentration can also be increased slightly. When topdressing, powdered organic fertilizer or chemical fertilizer is also often applied to the pot surface, but the amount must not be too much, otherwise it will harm the roots, affect absorption and even cause the plant to die.

Shading

Perennial flowers grown in a greenhouse receive mostly scattered light and are sensitive to strong outdoor light. When moved outdoors in spring, a shade shed needs to be set up, with a shading rate of about 40% to 60%.