The Latest Cultivation Techniques and Methods Tutorial for Finger Citron
Finger citron is a tropical and subtropical plant that prefers a warm, humid environment with ample sunlight. It is not tolerant of severe cold, fears frost and drought, and is shade-tolerant, barren-tolerant, and waterlogging-tolerant. It is best cultivated in areas with abundant rainfall and no freezing in winter. The optimal growth temperature is 22-24°C, the overwintering temperature should be above 5°C, the most suitable annual rainfall is 1000-1200mm, and the suitable annual sunshine duration is 1200-1800 hours. It is suitable for growing in acidic loam, sandy loam, or clay loam with deep, loose, fertile soil rich in humus and good drainage.
In the main production areas of Guangdong Province, namely Gaoyao City and Deqing County, the average annual temperature is 22°C, the average temperature in January, the coldest month, is 13.2°C, the extreme minimum temperature is -1°C, the average temperature in July, the hottest month, is 28.6°C, the average annual rainfall is about 1600mm, and the annual sunshine duration is 1815 hours. In well-drained, fertile rice fields with slightly acidic soil, it grows well, with relatively high and stable yields.
Propagation Methods of Finger Citron
Finger citron can be propagated by cuttings, grafting, or air layering. For cuttings, the time is from late June to early to mid-July. Cut branches from healthy mother plants as cuttings; roots will develop in about 1 month, and sprouts in two months. After sprouting, they can be planted out. Long-branch cuttings can also be used: take 3-4 year old healthy branches and cut them into 50cm lengths as cuttings.
1. Cutting propagation
Preparation of cuttings: Before cutting, select healthy 7-8 year old mother trees, cut off vigorous, pest-free old healthy branches, remove leaves and tender shoot tips, and cut them into 17-20cm long cuttings. The survival rate of cuttings is over 90%, and the seedlings grow very vigorously. Young tree branches or water sprouts must not be used, because such branches often do not bear fruit easily after planting.
Land preparation and cutting: The seedbed should preferably be sandy soil with relatively deep soil, to facilitate future removal of seedlings. After selecting the land, plow deeply and rake fine, apply human and animal manure water, and make high beds 1.3m wide, with furrow width of about 30cm and depth of about 20cm. Cutting can be done in spring from February to March and in autumn from August to September, with autumn cutting being the best. Cuttings made in autumn can take root the same year, and after sprouting in the following spring they grow rapidly. When cutting, open horizontal grooves on the bed with a spacing of 23-27cm; insert the cuttings into the grooves at a plant spacing of 15-17cm, and never insert them upside down. Usually about 12000-15000 cuttings are needed per mu. After inserting, cover with soil and press firmly, leaving one bud at the tip exposed above the soil surface. If the soil is dry, water it.
Seedling stage management: After cutting, water and irrigate at any time; also build a shade shed, and do a good job of drainage when there is a lot of rain. When the seedlings are 7-10cm tall, remove the clustered weak seedlings, leaving only one strong seedling per plant. Weed in time, and apply light human and animal manure water or ammonium sulfate 3-4 times. After one year of cultivation, they can be transplanted.
2. Grafting propagation
Carry out in spring and autumn. Using citron or lemon as rootstock is better. Rootstock is generally propagated by cuttings or sowing. Grafting methods include:
Approach grafting: Carry out in early to mid-August to September. Select 4-5 year old rootstock plants with stem diameter of 2-3cm, well-developed root systems, and healthy growth. At the stem base, cut off the branches, leaving only one branch, then shave off some cortex downward on one side of the cut branch position. Then select a branch produced in spring or autumn of the previous year as the scion, similar in thickness to the rootstock, 5-7cm long. Also shave off part of the cortex on the lower side of the scion, then place the cut surface of the rootstock against the cut surface of the scion, make the two surfaces fit closely, bind tightly in the middle with plastic film, and they can heal in about one week. After healing, cut off the rootstock portion above the joint.
Side cleft grafting: In early to mid-March, cut the rootstock flat at 5-7cm above the ground, smooth it with a grafting knife, and select a smooth part slightly with wood to make a slant cut, 1-1.5cm deep. The scion should retain 2-3 buds, and its lower end should be cut into a wedge shape 1-1.5cm long. Then align one side of the rootstock cut with the scion bark, insert tightly into the rootstock cut, and bind with plastic film. Generally after half a month it heals and sprouts and grows. At this time, loosen the soil and weed. After 45-60 days, shoots begin to emerge. At this time, remove the binding material, otherwise the new shoots are easily bent.
Cultivation Techniques of Finger Citron
Fertilization of finger citron should be determined according to tree age and growth condition. Generally, in the first 3 years, apply quick-acting organic fertilizer once a month from March to August; after entering the full fruiting period, topdress 3 times a year, respectively before flowering, during young fruit stage, and after harvesting, applying bran cake, compost, human and animal manure and urine together with phosphorus and potassium fertilizer or compound fertilizer in time, with special attention to applying winter fertilizer well.
Before finger citron enters the fruiting period, shoot-promoting fertilizer should be applied well: that is, apply quick-acting chemical fertilizer and farmyard manure once 10 days before spring shoots, summer shoots, and autumn shoots emerge. Generally, apply about 30g urea per plant, mix 100g phosphate fertilizer with 5kg chicken and cow manure, and apply it in a ring-shaped trench 30cm wide and 25cm deep in combination with intertillage and weeding, then cover with soil and seal tightly. Do not fertilize after September to prevent excessive growth of late autumn shoots.
After planting, finger citron can enter the fruiting period in the second year and can continuously bear fruit for about 30 years. It should be fertilized four times each year. The first is pre-flowering fertilizer, preferably applied in mid-March, with 5kg decomposed human manure and urine per plant; the second is during the peak flowering period, when fertilizer demand is relatively large, with 5kg decomposed chicken and cow manure and 150g urea per plant; the third is fruit-strengthening fertilizer applied around “Minor Heat”, with heavy application of phosphorus and potassium fertilizer to promote fruit enlargement and increase yield, applying 1 kg compound fertilizer mixed with 5kg decomposed chicken and cow manure per plant, and at the same time spraying 100g potassium dihydrogen phosphate diluted in 50kg water as a foliar fertilizer once, which is very beneficial for promoting vigorous tree growth and fruit enlargement. The fourth is post-harvest fertilizer; after harvesting in September to October, dig symmetrical trenches 40cm wide and 40cm deep on both sides of the plant along the canopy drip line, apply 10kg decomposed chicken and cow manure and 1kg compound fertilizer per plant, mix them, and return the soil to the pit.
After cutting seedlings or grafted seedlings have been cultivated for one year, when the seedlings reach 50cm tall, they can be planted in either spring or autumn. It is better when the temperature begins to warm in February and new buds are about to sprout. Generally, for cultivated land, first arrange drainage ditches around the perimeter, and dig holes at a spacing of about 3m between plants and rows. If planting along field edges and corners, it can be slightly denser. The hole diameter is about 50cm and the depth is 30cm. The soil in the hole should be fine, preferably arranged in a triangular pattern. Plant one seedling per hole, and it must be planted upright, with fibrous roots spreading in all directions. Cover the roots with fine soil, lift gently several times to make the roots and soil connect tightly, then cover with fine soil and tread firmly, and finally cover with soil slightly higher than the ground.