How are tulips cultivated and managed? These technical points need to be mastered

1. Preparation before planting First check whether the tulip bulbs have pests or diseases. If they are already infected or beginning to rot, they must be removed and burned. After removing diseased bulbs, soak the bulbs in a fungicidal solution for disinfection, for example, soak in a 600-fold chlorothalonil solution for 20-30 minutes. Around mid-August, cut open 3-4 tulip bulbs and observe the development of the internal nose (that is, the already differentiated flower stem). Those with a nose 3-4 mm long, ivory-colored and firm are good; whitish ones are not considered good, and flat ones are also not ideal.

Choose sandy loam rich in humus and well drained, make raised beds more than 20 cm high, and one month before planting irrigate with a 1%-2% formalin solution and cover to disinfect the soil. The bottom layer of the cultivation bed is best lined with coarse particles such as cinders, apply fully decomposed compost as base fertilizer, water thoroughly, and 2-3 days before planting carefully plow and harrow to ensure the soil is loose.

2. Planting In the Yangtze River Basin, planting can be done from late September to late November. The planting depth is generally 2 times the height of the bulb, and the spacing between plants and rows is 9 cm x 10 cm. For cut flower cultivation, a shallow planting method with the bulb shoulders exposed can also be used. Note that the bulbs need to be disinfected before planting by soaking in a thiophanate or potassium permanganate solution for 15-20 minutes.

Because the soil temperature is high, tulips may undergo devernalization, so rather than planting early, it is better to plant slightly late; generally, planting from late October to November is best. Although in natural-flowering cultivation the planting time will not affect the flowering period, because the tulip root system absorbs and stores a large amount of nitrogen throughout winter, planting too late will affect the normal development of the plant root system due to excessively low soil temperature, and whether the tulip root system develops well is the key to the success or failure of cultivation. After planting, spreading grass on the surface can prevent soil crusting, and early on it should be watered thoroughly to promote rooting.

3. Management after planting After tulips root, they go through a natural low-temperature stage. During this period, keep the soil moist, but prevent waterlogging. After leaves begin to emerge in early February, carry out field weeding, and promptly detect diseased plants, pull them out and destroy them. After the plants develop 2 leaves, apply 1-2 times of dilute liquid fertilizer or compound fertilizer; because tulips are relatively sensitive to potassium and calcium, appropriately applying inorganic fertilizers such as monopotassium phosphate and calcium nitrate can increase the firmness of the flower stem. After flowering ends in early May, apply 1-2 times of monopotassium phosphate or compound fertilizer to favor the swelling and development of new underground bulbs.

Tulips generally bloom in full from late March to mid-April. During the flowering period, fertilizer and water should be controlled, and measures such as rain protection and shading should be used to prolong the flowering period, while avoiding direct sunlight.

4. Bulb harvesting After the tulip leaves have basically turned yellow and withered, dig up the bulbs on a dry sunny day. Be careful not to damage the bulbs when digging, otherwise the wounds are very likely to become infected and rot. After digging up, remove the leaves, separate the bulbs by size, and place them in a shaded place to dry thoroughly or air-dry. If dried under strong light, they are also prone to disease.

Spread the bulbs out appropriately, or when boxing them fill only half a box, and store them through the summer under well-ventilated conditions at 20-25°C. During the plum rain season, especially pay attention to ventilation and cool conditions in the storage room; in summer, turn the boxes 2-4 times and remove rotten bulbs.

5. Pest and disease control The main diseases of tulips are viral diseases, bulb rot, and rust mites. Control methods include: choosing virus-free bulbs for cultivation as much as possible; carrying out thorough soil disinfection and bulb disinfection; promptly burning diseased bulbs and diseased plants; and scattering disulfoton granules to prevent rust mites. In addition, tulips are also prone to physiological diseases from calcium deficiency and boron deficiency, which should be noted in production.

(1) 5°C and 9°C forcing cultivation techniques

The characteristics of forced cultivation of tulip cut flowers are: storing the bulbs in a low-temperature storage, and in the crop rotation system of protected cultivation, about 50 days can be used to grow one season; planting can be done from mid-October to the end of March, and the flowering period is from late November to the end of May.

1. Cold storage method After the bulb flower buds have completed differentiation, place them around August 10 under 13-15°C for pre-cooling treatment for 2-3 weeks, then carry out formal cold storage at 2-5°C for about 8 weeks. The 5°C cold storage treatment technique is suitable for most varieties, and 5°C cold treatment is based on 8 weeks. Some tulip varieties can use the 9°C cold storage treatment technique. The method is to store at 9°C for 12-16 weeks, of which the last 6 weeks require planting the bulbs in wooden boxes or plastic boxes, watering them, and then placing them into a 9°C rooting cold-air storage, where the plants root and sprout. In 5°C forcing cultivation, it takes about 50-60 days from planting the bulbs to flowering, while the greenhouse time for 9°C box cultivation is only about 25 days.

If after leaf emergence the leaves spread horizontally and elongate slowly, this indicates insufficient low-temperature exposure; conversely, if the leaves are upright and thin, appearing leggy, and the anthers are dead, this indicates excessive low temperature. Generally speaking, after about 70 days of pre-cooling plus true cooling, dormancy is broken. If low-temperature exposure is insufficient, it can be promoted by dropping a 400 mg/liter gibberellin solution between the leaf sheaths. Note that because gibberellin is most easily absorbed into the plant body through the leaf axils, spraying is difficult to make effective.

In forced cultivation of tulips, due to insufficient cold storage treatment, some varieties are prone to blind flower phenomenon, which can also be prevented by dropping 0.5-1 ml of 400 mg/liter gibberellin solution into the central sheath. In addition, different varieties have different sensitivities to blind flower; some early-flowering varieties such as Merry Christmas and Yokohama are very prone to blind flower if they encounter relatively high temperatures early on

2. Temperature and light management The management method for forced cultivation of tulips is the same as conventional cultivation, and the optimum temperature for growth is 15-18°C. When the air temperature drops below 5°C, tulips stop growing; when the night temperature drops below 10°C, plastic sheeting must be added for insulation or heating, so that the daytime temperature in the protected area remains below 25°C and the night temperature is around 14°C. However, when temperature and humidity are too high, they are also prone to legginess and to gray mold and deformed flowers, so attention should be paid to ventilation in the protected area. Once diseased plants are found, they should be promptly pulled out and burned.

3. Planting precautions

(1) Before planting, through measures such as shading and watering, strive to lower the soil temperature to around 10°C. Within 2 weeks after planting, the optimum temperature should be around 14-16°C to favor good rooting of the bulbs.

(2) Before planting, be sure to remove the scale skin near the outer base of the tulip bulb, and do not injure the basal plate. When pressing the bulbs in, do not use too much force. The bulbs should be planted in slightly moist soil.

(3) Maintain a low salt level in the soil and water source. If the soil salt content is too high, water thoroughly 2 weeks before planting to leach out the salts. Soil pH must not be lower than 6.

(4) Continuous cropping of tulips is strictly prohibited; crop rotation is required.

(5) Keep the soil continuously moist as much as possible, and when watering, keep the upper layer of soil intact. The standard for moderate watering is that the soil below the bulbs can be squeezed into a ball in the hand, which ensures the humidity needed by the plants.

(6) After planting 5°C bulbs, cover with about 5 cm of soil; 9°C bulbs generally use the box cultivation method, can be planted shallowly with the shoulders exposed, and planted at high density reaching more than 200 bulbs per sq m.

(7) After confirming that the plant root system has developed well, apply calcium nitrate fertilizer at 50 grams per sq m; at this time the temperature can also be increased to 17-19°C.

(8) When tulip plants have grown to 5-10 cm, the bulbs that have not emerged must be dug out one by one for inspection. These bulbs should be removed immediately and destroyed to avoid harming other plants.

(9) Prevent excessive day-night temperature differences. Through ventilation measures, keep relative humidity no higher than 80%.

(10) Harvesting should be carried out when the flower buds have fully colored and the flowers are closed. After harvesting the whole plant, cut off the bulb part, and soak the cut flowers in a preservative solution containing 10 grams of calcium nitrate per liter for 30-60 minutes. After the water treatment, place the cut flowers into a 2-5°C cold storage as soon as possible, with relative humidity not lower than 90%. If the cut flowers are placed in cold storage, note that fruits, bulbs, and fresh cut flowers cannot be placed in the same cold storage.