Detailed Guide to Gladiolus Planting Methods and Cultivation Management Points

Gladiolus is a light-loving long-day plant that cannot tolerate freezing cold; in summer it prefers a cool climate and cannot withstand excessive heat. The corms begin to sprout at 4-5°C and grow best at 20-25°C. It likes fertile, deep sandy soil and requires good drainage; it should not be planted in heavy clay soil where waterlogging is likely. Summer growth in Northeast and North China is better than in Guangzhou and Shanghai. In Shanghai it can safely overwinter outdoors, while in the north the corms must be dug out and stored indoors for the winter.

Propagation Methods

Gladiolus propagation is mainly by corm division. The new corms bloom the following year. To speed up propagation, the corms can also be cut into sections; each section must have a bud and a root-forming part. Coat the cut surface with plant ash, let it dry slightly, then plant. When breeding new cultivars, seed propagation is mostly used. Seeds collected in autumn are sown immediately and have a high germination rate; in winter the seedlings are moved into a greenhouse for cultivation, and the following spring they are planted out in the open field in divisions. With strengthened management, some plants can bloom in autumn.

Field Management

For growing gladiolus, choose a sunny, well-drained sandy loam rich in humus; although it can grow and bloom in clay soil, the renewal corms develop poorly and few small corms form under the large corms. Before planting, apply sufficient base fertilizer to the soil, preferably one rich in phosphorus and potassium. Planting depth varies with soil properties and corm size, generally 5-10 cm, with spacing of 15-25 cm between plants and rows. Apply topdressing 3 times during the growing period. The first is after two leaves have unfolded, to promote bud, stem and leaf growth; the second is when the stem has 4 leaves and is elongating and budding, to promote sturdy flower stalks and large blooms; the third is after flowering, to promote renewal corm development. Sunlight during the growing period favors flower bud differentiation and development. In summer, if drought occurs, irrigate fully, and in the rainy season pay attention to drainage and irrigation.

Cultivation Points

1. Land preparation and fertilization: For planting gladiolus, sandy loam should be chosen, with a deep, loose soil layer and good drainage; waterlogging must be avoided. Make raised beds 20 cm high and 1 m to 1.5 m wide. Fertilization should balance nitrogen, phosphorus and potassium. Since gladiolus is a shallow-rooted plant, fertilizer should be applied shallowly. Topdressing is applied at the two true-leaf stage (after flower bud differentiation) and at the heading stage: apply dilute manure water plus urea once, apply a heavy potassium fertilizer once at the mid-stage, and in the later stage pay attention to controlling nitrogen to prevent excessive vegetative growth and lodging. For plots mainly producing corms, potassium fertilizer should be emphasized.

2. Corm selection and treatment: After determining the cultivar to grow, pay attention to selecting corms. When selecting, make sure cultivars are not mixed, and choose seed corms that are free of pests and diseases and whose buds are undamaged. Before planting, soak the graded corms in water for 15 minutes first, then soak them for half an hour in 0.1% mercuric chloride or 80-times formalin solution for disinfection. After removing, rinse them clean before planting.

3. Planting time: Under natural conditions, planting is generally done in April-May when the soil temperature is about 10C. For year-round production, it should be determined according to different flower supply periods. Under conditions where temperature and light are guaranteed, those required to go on the market before New Year's Day should be planted in early September; those for the Spring Festival can be planted in late September; those supplying cut flowers in early spring can be planted from late November to late December. For flowering from late May to early June, germination can be forced in early February and open-field planting done in early April; for National Day flowering, planting can be done from early June to mid-July.

4. Breaking dormancy: Under low-temperature conditions, corms remain dormant continuously for about 3 months. If earlier planting is needed, first treat them at a high temperature of 35°C for 15-20 days, then treat them at a low temperature of 2C-3 C for 20 days to break dormancy. During this period, however, the corms should be kept dry, as excessive moisture easily causes corm rot.

5. Planting specifications: These vary with the plant type of the cultivar. Large plant types use 20 cm square spacing; small and medium plant types use 10-15 cm square spacing. Planting depth is generally 3 cm to 10 cm. To prevent lodging, when planting the corms, first place 2 layers of 20 cm square nylon netting on the planting bed, and later, as the plants grow taller, tighten support strings layer by layer to prevent the plants from lodging and the flower stems from bending.

Cultivation Management

1. In production, planting is mainly done with corms. In spring, grade the corms by size and soak them for 30 minutes in a mixture of 800-times 70% thiophanate-methyl powder or 1000-times carbendazim plus 1500-times captan, then force sprouting at 20-25°C; after about 1 week they can be planted. For cultivars seriously infected by viruses and showing obvious degeneration, shoot-tip virus elimination can be used to rejuvenate the plants.

2. Conventional gladiolus cultivation refers to cultivation under natural conditions, generally choosing seed corms with a diameter of more than 2.5 cm. Planting methods include ridge planting and bed planting, with a planting depth of 5-10 cm. When gladiolus produces its second leaf, this is exactly the time of flower bud differentiation, and it is especially sensitive to environmental factors. If it encounters low temperature and weak light, the number of “blind flowers” increases. Generally, when preparing the land, apply 6-9 kg of nitrogen, 6-12 kg of phosphorus and 7-12 kg of potassium per mu. Throughout the growing season, topdressing is needed 3 times, namely when 2-3 leaves have emerged, when the inflorescence emerges from the leaves, and 15 days after flowering.

3. For forced gladiolus cultivation, the seed corm dormancy must first be broken. After the seed corms are harvested, under natural conditions, dormancy can only be broken after the low-temperature influence from late autumn to early winter. Forced cultivation must break dormancy artificially: after harvesting the seed corms, first treat them at a high temperature of 35°C for 15-20 days, then treat them at a low temperature of 2-3°C for 20 days, then plant them, and they will sprout and grow normally. If flowers are required for January-February, plant in October-November; if planted in December, they will bloom in March-May. That is, from planting to flowering takes 100-120 days. The spacing for forced cultivation is 15cm×15cm or 25cm×7cm, with 40-60 seed corms planted per square meter. After planting, the daytime temperature should be kept at 20-25°C and the nighttime temperature at about 15°C.

4. Gladiolus can also be grown with delayed cultivation. After harvesting, store the seed corms in a dry cold storage at 3-5°C, then plant them again in a greenhouse in July-August of the following year; the management work is the same as for forced cultivation.

5. Cut flowers can be harvested 60-100 days after planting, with the specific time depending on the cultivar. The suitable harvest time is when the lower 1-5 florets of the inflorescence show color. Generally, cut them together with 2-3 leaves, being careful not to damage the leaves remaining on the lower stem, so that they can continue to supply nutrients to the new corms and daughter corms. The cut flower stems should be graded and packaged, placed in a storage room at about 4°C, and delivered to consumers within 3-7 days. If storage or transport time is too long, quality will decline.

Pest and Disease Control

1. Penicillium rot: During harvest and transport, try not to injure the seed corms; before planting, soak them in a 2% potassium permanganate solution for 1 hour; during growth, pull out diseased plants at any time.

2. Dry rot: When planting, select disease-free mother corms, and during growth pull out diseased plants promptly.

3. “Blind flower” is a physiological disease that mostly occurs in protected cultivation in winter. The way to prevent it is to ensure suitable temperature and light and to choose cultivars tolerant of low temperature and short-day conditions. The main pest is the two-line mucus slug, which can be killed by spraying lime water or ammonia water; scatter lime powder around the garden to stop them from entering; and hand-collect and kill them. Gladiolus corm diseases are relatively serious, so corm disinfection is an important measure. The method is to remove the corm skin, soak in clean water for 15 minutes, then soak in 80-times formalin solution for 30 minutes or 0.2% amobam for 10 minutes, then rinse with clean water before planting. In summer, high temperature and high humidity make it prone to damping-off. Besides spraying 1000-times thiophanate solution or applying 10 g of zineb per square meter combined with irrigation for control, attention should also be paid to avoiding drooping flowers; if nematode damage is found, the seed corms should be dug up and burned, and in addition to soil disinfection, crop rotation must also be carried out.

4. Gladiolus copper-green chafer

The harm of the gladiolus copper-green chafer is widely distributed in China and serious. Both adults and larvae can cause damage, with larvae causing the most serious harm. It mainly damages by larvae feeding on germinating seeds in the soil, causing missing plants and broken rows; biting off rhizomes and root systems, causing plants to die, and the wounds are easily invaded by pathogens, causing plant diseases.

① Seed treatment before sowing: 50% phoxim emulsifiable concentrate or phoxim microcapsule formulation can be used for crop seed dressing, generally with an effective ingredient concentration of 0.05%-0.1%, or 40% isofenphos-methyl emulsifiable concentrate with an effective ingredient concentration of 0.04%-0.08% for seed dressing.

② Soil treatment: 50% phoxim emulsifiable concentrate can be used at 3.7-4.5 liters per hectare, applied into the soil together with irrigation water.

③ Deep plowing in spring and autumn to eliminate pests. Rational irrigation, increased application of decomposed manure, and soil improvement can thereby enhance its insect resistance.

④ Taking advantage of the adult's phototaxis, use blacklight traps to kill them.

⑤ Chemical control: During the peak emergence period of adults, spray with 800-times 40% dimethoate or omethoate emulsifiable concentrate; or 1000-times 90% trichlorfon.

⑥ Protect and utilize natural enemies.

How to Grow Gladiolus, Gladiolus Cultivation Methods

How to grow gladiolus. As a common plant, gladiolus, together with roses, carnations and gerbera, is known as one of the “world's four major cut flowers.” So many flower lovers grow gladiolus at home. Below are the compiled cultivation methods and care points for gladiolus, hoping to help flower lovers growing gladiolus.

Gladiolus should be planted in soil with good aeration and water permeability. If the soil at the planting site is relatively heavy, organic fertilizer, straw or sand can be mixed in before planting to improve it. Gladiolus requires a soil pH between 6 and 7. A soil pH below 5 can cause fluoride toxicity. To raise soil pH, lime must be added to the soil one month before planting (mixed evenly with the soil) for correction; a soil pH above 7.5 can cause nutrient deficiency, which can be prevented by applying more organic fertilizer to the soil.

Before gladiolus emerges, irrigate once every 10 days. After the seedlings have all emerged, do not let them dry out, otherwise the leaf tips easily turn yellow. After the flower scape appears, they must not suffer drought even more. In summer, with no rain, irrigate once every 4 days. After flowering, irrigation should be stopped to prolong the flowering period.

Gladiolus likes a warm, humid climate, dislikes high temperature and severe heat, and is not cold-tolerant. The most suitable temperature for growth is 20-25°C. When the early spring soil temperature rises above 5°C, the corms can sprout; when the summer temperature rises above 35°C, growth is inhibited. Gladiolus generally blooms about 3 months after planting, but the cultivation cycle is greatly affected by the temperature during the growing period. The higher the temperature during the growing period, the shorter the cultivation cycle. For example, when the average temperature during the growing period is 12°C, gladiolus takes 110-120 days from planting to flowering; when the average temperature reaches 15°C, only 90-100 days are needed; at 20°C, 70-80 days are needed; and at as high as 25°C, the cultivation cycle is only 60-70 days.

Gladiolus is not shade-tolerant and is a long-day plant. The most suitable light is 16 hours per day. Cut flower cultivars are greatly affected by light. Sufficient sunlight makes them grow robustly, with strong stress resistance, and the flower colors are vivid and long-lasting, but in hot summers, strong direct sunlight should also be avoided.

Gladiolus is a shallow-rooted plant, so fertilizer should be applied shallowly, and fertilization should balance nitrogen, phosphorus and potassium. Topdressing is applied at the two true-leaf stage (after flower bud differentiation) and at the heading stage: apply dilute manure water plus urea once, apply a heavy potassium fertilizer once at the mid-stage, and in the later stage pay attention to controlling nitrogen to prevent excessive vegetative growth and lodging. For plots mainly producing corms, potassium fertilizer should be emphasized.

Common diseases of gladiolus include corm rot and leaf blight; common pests include thrips and slugs. Pay attention to care and handle them promptly.

1. After receiving, cut a small section from the lower end of the flower stem at a 45° angle, remove the flowers at the lowest end that would affect vase placement, and remove the leaves that would be submerged in water.

2. Put 1/3 water in the vase. With preservative, change the water and trim the stems every 2-3 days; without preservative, change the water every 1-2 days. Clean the mouth of the vase to avoid bacterial growth.

3. Avoid direct sunlight and wind.

Gladiolus Cultivation Methods

Gladiolus is a light-loving long-day plant that cannot tolerate freezing cold; in summer it prefers a cool climate and cannot withstand excessive heat. The corms begin to sprout at 4-5°C and grow best at 20-25°C. It likes fertile, deep sandy soil and requires good drainage; it should not be planted in heavy clay soil where waterlogging is likely. Summer growth in Northeast and North China is better than in Guangzhou and Shanghai. In Shanghai it can safely overwinter outdoors, while in the north the corms must be dug out and stored indoors for the winter.

Propagation Methods

Gladiolus propagation is mainly by corm division. The new corms bloom the following year. To speed up propagation, the corms can also be cut into sections; each section must have a bud and a root-forming part. Coat the cut surface with plant ash, let it dry slightly, then plant. When breeding new cultivars, seed propagation is mostly used. Seeds collected in autumn are sown immediately and have a high germination rate; in winter the seedlings are moved into a greenhouse for cultivation, and the following spring they are planted out in the open field in divisions. With strengthened management, some plants can bloom in autumn.

Field Management

For growing gladiolus, choose a sunny, well-drained sandy loam rich in humus; although it can grow and bloom in clay soil, the renewal corms develop poorly and few small corms form under the large corms. Before planting, apply sufficient base fertilizer to the soil, preferably one rich in phosphorus and potassium. Planting depth varies with soil properties and corm size, generally 5-10 cm, with spacing of 15-25 cm between plants and rows. Apply topdressing 3 times during the growing period. The first is after two leaves have unfolded, to promote bud, stem and leaf growth; the second is when the stem has 4 leaves and is elongating and budding, to promote sturdy flower stalks and large blooms; the third is after flowering, to promote renewal corm development. Sunlight during the growing period favors flower bud differentiation and development. In summer, if drought occurs, irrigate fully, and in the rainy season pay attention to drainage and irrigation.

Cultivation Points

1. Land preparation and fertilization: For planting gladiolus, sandy loam should be chosen, with a deep, loose soil layer and good drainage; waterlogging must be avoided. Make raised beds 20 cm high and 1 m to 1.5 m wide. Fertilization should balance nitrogen, phosphorus and potassium. Since gladiolus is a shallow-rooted plant, fertilizer should be applied shallowly. Topdressing is applied at the two true-leaf stage (after flower bud differentiation) and at the heading stage: apply dilute manure water plus urea once, apply a heavy potassium fertilizer once at the mid-stage, and in the later stage pay attention to controlling nitrogen to prevent excessive vegetative growth and lodging. For plots mainly producing corms, potassium fertilizer should be emphasized.

2. Corm selection and treatment: After determining the cultivar to grow, pay attention to selecting corms. When selecting, make sure cultivars are not mixed, and choose seed corms that are free of pests and diseases and whose buds are undamaged. Before planting, soak the graded corms in water for 15 minutes first, then soak them for half an hour in 0.1% mercuric chloride or 80-times formalin solution for disinfection. After removing, rinse them clean before planting.

3. Planting time: Under natural conditions, planting is generally done in April-May when the soil temperature is about 10C. For year-round production, it should be determined according to different flower supply periods. Under conditions where temperature and light are guaranteed, those required to go on the market before New Year's Day should be planted in early September; those for the Spring Festival can be planted in late September; those supplying cut flowers in early spring can be planted from late November to late December. For flowering from late May to early June, germination can be forced in early February and open-field planting done in early April; for National Day flowering, planting can be done from early June to mid-July.

4. Breaking dormancy: Under low-temperature conditions, corms remain dormant continuously for about 3 months. If earlier planting is needed, first treat them at a high temperature of 35°C for 15-20 days, then treat them at a low temperature of 2C-3 C for 20 days to break dormancy. During this period, however, the corms should be kept dry, as excessive moisture easily causes corm rot.

5. Planting specifications: These vary with the plant type of the cultivar. Large plant types use 20 cm square spacing; small and medium plant types use 10-15 cm square spacing. Planting depth is generally 3 cm to 10 cm. To prevent lodging, when planting the corms, first place 2 layers of 20 cm square nylon netting on the planting bed, and later, as the plants grow taller, tighten support strings layer by layer to prevent the plants from lodging and the flower stems from bending.