Detailed Explanation of Key Techniques for Forcing Cut Tulips

Tulips belong to the genus Tulipa in the lily family (Liliaceae), perennial bulbous herbaceous plants. Because of their unusual flowers, large blooms and brilliant colors, symbolizing "holiness and happiness," they are highly favored by people.

1. Select good varieties. Cut tulip bulbs are generally imported from the Netherlands. First, select as few late-flowering varieties as possible; generally choose mid-season, tall-stemmed varieties, with a comprehensive color mix to suit the needs of consumers at different levels. Red varieties include Apollo, Parade, Miss Holland, Le France, and Remember Le Feber; yellow varieties include Golden Apollo and Golden Parade; white varieties include Ireland, White Dream, and Chanting One; pink varieties include Gander, Pink Diamond; orange varieties include Prince; bicolor varieties include Lin Mark (red and white), Variegated Youth (yellow and red), and Kees Nelis (red and yellow), etc. Second, select bulbs with a circumference of 12 cm or more. Fresh cut flowers produced from large-sized bulbs are larger, more brilliantly colored, more uniform, and last longer in the vase. Third, select 5-degree bulbs that have undergone complete low-temperature treatment. When purchasing bulbs, check the temperature record sheet of the @#@136@#@ trader for low-temperature treatment during sea transport; if the low temperature is insufficient or the treatment time is not long enough, follow-up work such as further low-temperature treatment should be carried out.

2. Reasonably determine the sowing date. Cut tulips are generally planned to go on the market between the Spring Festival and Valentine's Day. Based on the theoretical marketing value of the full growth period of cut tulips (55-65 days), arrange the sowing date 7-10 days in advance (for example, the 2004 Spring Festival was January 21, so the reference sowing date could be arranged around November 10). Purposes: (1) to appropriately deduct time delayed by overcast and rainy days; (2) when the low-temperature treatment of bulbs is not in place, remedial measures can be taken by intensifying low-temperature management in the greenhouse during the early period; (3) to facilitate artificial control of the marketing time of fresh cut flowers.

3. Planting specifications. The spread of tulips is 10-15 cm. Therefore, the planting density is very flexible, and the plant and row spacing can be 10-15 cm x 15-20 cm, that is, 20000-35000 bulbs can be planted per mu. Varieties with a large spread (such as Apollo) can be planted sparsely, and varieties with a small spread (such as Le France) can be planted densely. High planting density helps increase the height of cut flower stems, but it easily leads to disease. When planting, the bulbs should be placed upright, with the top facing up, and covered with 3-5 cm of soil. Deep planting helps increase cut flower height and is beneficial for medium-height varieties, but it will delay the flowering period by a few days.

4. Fertilizer management. Cut tulip cultivation does not require too much fertilizer. Apply 3000-5000 kg of organic fertilizer and 50 kg of high-efficiency compound fertilizer per mu as base fertilizer. Organic fertilizer should be fully decomposed, and inorganic chemical fertilizer should be applied 15-20 days before planting. The fertilizer should be fully mixed with the soil, raked and harrowed, and beds should be made. Starting from the emergence of young shoots, apply a 0.3% urea solution as a top dressing once every 15 days; from bud stage to one week before flower harvesting, spray a mixed nutrient solution of O.2-O.3% "Chunquan 883" and potassium dihydrogen phosphate once every 7-10 days.

5. Water management. After the beds are prepared and sun-dried 15-20 days before planting, irrigate thoroughly once one week before planting, and immediately irrigate thoroughly with cool water once on the day of sowing. During the growing period, water generally once every 15-20 days, preferably in the morning, watering thoroughly and evenly. After watering, pay attention to ventilation and cooling, and do not splash cool water onto the leaves when watering.

6. Temperature and humidity regulation. The optimum temperature for tulips is 15-18 degrees Celsius, and the maximum should not exceed 25 degrees Celsius. Implementing low-temperature management in the early growth stage is the key to cultivating tulips and improving cut flower quality. Within the first 2 weeks after planting, the soil temperature should be kept below 12 degrees Celsius, which can be achieved by covering the soil with straw or covering the greenhouse with shade netting and other means to lower the temperature. In mid-to-late November, cover with film to keep warm, using 0.12 mm thick long-life anti-drip polyethylene film. In early December, put up straw curtains for nighttime insulation. Before mid-December, keep the greenhouse temperature below 20 degrees Celsius during the day as much as possible. Throughout the growing period, keep the nighttime temperature in the greenhouse above 6 degrees Celsius. The relative humidity in the greenhouse must not be higher than 80% or lower than 60%; humidity can be adjusted by watering and ventilation. After the flower buds emerge, increase humidity management to help increase flower stem height, but closely monitor the occurrence of diseases such as tulip gray mold. When the daytime greenhouse temperature exceeds 25 degrees Celsius or the humidity exceeds 80%, pay attention to using ventilation to lower the temperature and remove moisture.

7. Supplementary lighting. Tulip growth requires ample sunlight. Producers with the conditions can adopt the method of hanging 1 200-watt high-pressure sodium lamp (with a reflector installed) every 30 sq m, starting supplementary lighting from the 2-leaf stage until flowering. Turn on the lamps for 3-5 hours every evening after lowering the straw curtains. This measure helps produce high-quality cut flowers with large blooms, brilliant colors and tall stems, and can also advance the flowering period.

8. Control of main diseases and insect pests. Under film solar greenhouse conditions, tulip diseases and insect pests include viral disease, gray mold, aphids, etc. Comprehensive control measures are as follows: (1) rotate with other plants such as legumes; (2) when planting, pick out diseased and damaged bulbs and treat them separately; (3) continuously inspect, dig out and destroy diseased plants; (4) strengthen ventilation and light transmission in the greenhouse, and also strengthen ventilation and dehumidification on overcast and rainy days; (5) for the control of diseases such as gray mold, spray with 1000-fold dilution of 20% Sumilex.

9. Timely harvesting. Cutting is best done when the flower bud just begins to show color (before the bud opens), usually once each in the morning, midday and evening. Those whose plant height does not reach 35 cm should be pulled up with roots. After harvesting, package them well and place them in a cold room for sale.