After collecting enough grapefruit, try to soak in water on the same day.
Soak in water for about 5-7 days and change the water every day. Otherwise the water will stink.
The water soaked in seeds will feel very slippery and sticky, much like Aiyuzai. Because there is a kind of gum outside the seed that will stick, if you try to soak it in water for a long time, it will look like jelly.
It is easier to germinate if the outer mucosa must be washed away. If grapefruit seeds are planted directly without peeling, they will actually germinate, only a few days later.
Plant the bud point down, that is, the tip down, into the culture soil, and it is not necessary to bury it all. It is necessary to expose a little round part and keep the soil moist, and it will germinate in about 7~ 10 days. If the soaking process is smooth, the seeds will crack slightly.
How tall the seedlings will grow depends on the size of the flowerpot you use and the depth of the soil. If you want to keep them small and lovely, don't plant them in flowerpots that are too deep, because the roots of grapefruit seedlings don't have enough space to grow, so naturally they won't grow very tall.
Yes, it needs grafting. Attached are cultivation techniques for your reference, including grafting techniques.
If you build an orchard, you must use grafting.
1. Seedling raising:
Rootstock is the best, which grows fast after grafting, bears early fruit, has high yield and good fruit quality. Sowing is generally carried out in the field, and a small plastic arch shed should be built to keep warm. Emerge in the same year, and germinate in the next autumn, which can be as early as 1 year. Grafting is usually carried out from early March to early April, and the autumn shoot or spring shoot scion is about15-25 cm; In August -65438+ 10, T-type bud grafting is commonly used. In the first ten days of March of the following year, after the bud grafting survives, it is cut off 3-5 cm away from the bud. When the spring shoots stop growing, all the grafting piles are cut off.
2. Building a garden:
(1) Land preparation and slotting
After soil preparation, pump the trench, with the trench width of 100 cm and the trench depth of 60-80 cm. Base fertilizer, namely garbage, straw, branches and leaves, turf, etc. Layered application, 5000- 10000 kg per mu, fence fertilizer, compost, cake fertilizer, etc. Apply to the upper layer, 250 kg per mu.
(2) Colonization
Planting density: grapefruit grows vigorously and has a large crown. Grafted trees enter the full fruit stage after 6-7 years, so the planting density should not be too dense. Planting 45 plants per mu on slopes above 20 degrees; 40 plants per mu 10-20 degrees; On the gentle slope below 10 degree, about 35 plants are planted per mu. Blending pollination trees: Grapefruit has strong fruiting ability, but cross pollination can improve fruit setting rate and increase fruit, so it is suitable for single-row mixed planting. Planting time: pomelo can be planted in spring (March) and autumn (165438+1October), and the first half of March is the best. Planting should be carried out in cloudy or sunny evening, not in rainy days or when the soil is too wet.
fertilize the soil or land
(1) young tree fertilization
The immature root system is shallow in distribution and weak in fertilizer absorption, so the principle of giving attention to both fertilizer and water and applying thin fertilizer frequently should be mastered. Fertilize +0 1 month in March-July and June 1 time. Among them, spring bamboo shoot fertilizer in March, summer bamboo shoot fertilizer in May and 1 1 winter fertilizer are essential. Young trees mainly use organic nitrogen fertilizer, such as human manure, decomposed manure, cake fertilizer, and appropriate amount of urea and other chemical fertilizers. Fertilization of young trees is mainly to promote the emergence of shoots in spring, summer and autumn, accelerate the formation of crown, and pay attention to regulating vegetative growth and reproductive growth to enhance the ability of drought resistance and freezing resistance.
(2) Fertilizing adult trees
Fertilization for adult fruit trees is mainly to achieve high quality, high yield and stable yield, and to adjust the relationship between vegetative growth and reproductive growth. Generally, fertilizer should be applied at least three times a year. Germination-accelerating fertilizer: it is applied before germination 10- 15 days in early March, and is mainly composed of available nitrogen fertilizer and appropriate amount of phosphorus and potassium fertilizer to promote the emergence of a large number of high-quality spring shoots. This fertilization is related to the yield of the current year and the following year, so it must be applied in time, early and in full. Fertilization accounts for about 30% of the whole year. Generally, 0.50-0.75 kg of urea and 0.25 kg of calcium superphosphate are applied to each plant. Strong fruit fertilizer: apply strong fruit fertilizer during the fruit expansion period from June to August, mainly nitrogen, supplemented by phosphorus and potassium. Fertilization accounts for about 30% of the whole year, depending on the number of results in that year. There are many fruits and a large amount of fertilizer, which can be applied twice in June and August. Generally, urea and compound fertilizer are 0.5 kg or 0.75 kg each, and calcium superphosphate and potassium chloride are 0.2 5 kg each. If there are few fruits, you can consider or not to apply strong fruit fertilizer to prevent sudden autumn shoots. Fruit picking fertilizer: 165438+ 10 was applied at the beginning of October, accounting for about 40% of the whole year. The growth of grapefruit fruit consumes a lot of nutrients, so it needs to be supplemented in time to restore tree vigor, improve cold resistance and overwintering ability, promote flower bud differentiation, and lay the foundation for growth and fruiting in the coming year. Fruit picking fertilizer should be combined with available fertilizer and organic fertilizer, nitrogen fertilizer and phosphorus and potassium fertilizer. Generally, 0.5 kg of urea, 0.5 kg of compound fertilizer, 5 kg of cake fertilizer, manure waste and other soil miscellaneous fertilizers are applied to each plant 100 kg. In addition, it can also be combined with spraying appropriate amount of urea and potassium dioxygen phosphate for topdressing outside the roots to supplement the needs of trees for nitrogen, phosphorus and potassium in time.
(3) shaping and pruning
1. Young tree shaping
After the seedlings are planted, they are cut and dried 30-40 cm above the seam. After pruning, select 3-4 new shoots with vigorous growth, uniform distribution around them and a certain interval between them as the main branches, and erase the rest. When the top of each main branch extends to about 40 cm, the core should be picked in time. On each main branch, choose 2-3 robust branches with appropriate positions as auxiliary main branches. Proper spacing should be kept between the main stem and the auxiliary main branches, so that the lateral branches of meristem can be fully illuminated. Always wipe off the branches that cross, overlap and disrupt the tree, and the branches and buds that are not in place.
2. Prune the result tree
Generally speaking, pomelo fruit trees only shoot in spring, with few shoots in summer and autumn, and have strong fruit-bearing ability. Therefore, the pruning of the first-bearing trees should be light rather than heavy. Generally, there are only overgrown branches, pests and diseases, dead branches, too dense and delicate branches, etc. If the location is improper, the branches should be thinned and more internal branches should be left, so the mother branches should not be cut short. The crown of adult trees has been formed, and the pruning objects are mainly the lateral branches on the main branches and various branches on them, with the aim of adjusting the balance between growth and fruit. The principle of pruning is that strong trees should be sparse, few short and dense branches, upright branches and lateral branches should be sparse, and drooping branches and weak branches should be left to facilitate flowering and fruiting. Weak trees mostly bear fruit on strong branches, so measures should be taken to remove the weak and keep the strong, and more leafy fruit branches should be kept.
3. Renewal of old trees
The best time for regeneration and pruning of old trees is before the germination of spring shoots or after the stop of growth, and 5-6 months before the occurrence of summer shoots. Old trees should be bare and updated, and the main branches and auxiliary branches should be retained when updating. All 3-4 year-old lateral branches on the crown should be cut off, and no leaves should be left on the crown to promote the occurrence of strong branches. After germination and shoot control, COVID-19 can be formed within 1-2 years, and the fruit can be restored. For some rotten branches that still have the ability to bear fruit, a part of them can be updated every year and a whole tree can be updated in 2-3 years through rotation.
(4) Pest control
1. Main diseases of grapefruit
The main diseases of grapefruit are Huanglongbing, canker, scab and anthracnose, and their control methods are the same as those of citrus, which can be used for reference. Ulcer does great harm to grapefruit. Canker disease is caused by bacteria, which mainly attacks new shoots, young leaves and young fruits, forming ulceration spots with approximate round, cork-like, rough surface and yellowish brown, with a diameter of 0.3-0.5 cm, causing defoliation and fruit drop, affecting growth and yield, and reducing the appearance and internal quality of fruits. The prevention and control methods are mainly prevention, comprehensive management and strict quarantine system, and disease-free mother tree gardens, cutting nurseries and seedling bases are established to prevent sick seedlings from coming out of the nursery. Comprehensive measures should be taken to prevent and control the application of sickbeds.
Clean the garden thoroughly. After harvesting, cut off the diseased branches and leaves, clean up the fallen diseased fruits and burn them on the spot. After clearing the garden, spray the mixture of stone and sulfur in an all-round way to eliminate the source of overwintering disease.
(2) Prevent and control pests infecting the disease source in time at each bamboo shoot picking stage. Such as leaf miners and malignant leafhoppers.
(3) Spraying the medicine every time after the bud of the new branch is exposed (before self-cutting) and every 10 and 30 or 50 days after the flower withers. Optional drugs are 1:2: 100 times bordeaux solution, 600- 1000 units of agricultural streptomycin plus 1% ethanol solution per ml, 500-800 times of 50% zineb aqueous solution, 500-800 times of 50% Bifidobacterium powder, etc.
2. Main pests of grapefruit
The main pests of grapefruit are mites such as red spider and rust tick, scale insects such as arrowhead scale and brown planthopper, citrus leaf miner and biting insect.
Mite control method: spraying 73% propargite EC 2000-4000 times, 50% cyhalothrin triazole 1500-2000 times and 20% dicofol EC 800- 1000 times; The control method can spray 40% omethoate EC 1000 times and 20% fenvalerate EC 3000 times 1-2 times continuously in the larval stage; Citrus leaf miner can spray 25% deltamethrin 2500-3000 times or 40% isocarbophos 800- 1000 times every 5- 10 days when most new shoots grow to 0.5-10 cm. The dead skin of the trunk can be scraped off before the adult emerges from the hole, and 40% dimethoate EC 1: 1 and kerosene can be applied to the injured part. At the peak of adult emergence, 80% dichlorvos EC 1000 times or 90% trichlorfon 1000-6544 times can be used.