After collecting enough grapefruit, try to soak it 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 feels slippery and sticky, much like Ai Yuzai. Because there is a kind of gum outside the seed that sticks together, if you try to soak it in water for a long time, it will look like jelly.
If the outer mucosa must be washed away, it is easier to germinate. If grapefruit seeds are planted directly without peeling, they will actually germinate, only a few days later.
Put the bud point down, that is, the tip down, into the culture soil, so it is not necessary to bury it all. It needs 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 them to grow 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 they naturally 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. After grafting, it grows fast, bears fruit early, 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. When seedlings emerge in the same year, they can germinate in the following autumn, which can be advanced by 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; Bud grafting is carried out in August -65438+ 10, and T-bud grafting is commonly used. In the first half of March of the following year, after the bud grafting survives, it is cut off at a distance of 3-5 cm from the bud, and all the grafting piles are cut off when the spring shoots stop growing.
2. Building a garden:
(1) Land preparation and slotting
After soil preparation, the ditch is pumped with a width of 100 cm and a depth of 60-80 cm. Base fertilizer, namely garbage, straw, branches and leaves, turf, etc. Layered application, the application rate per mu is 5000- 10000 kg, and fence fertilizer, compost, cake fertilizer, etc. can also be applied. Apply it to the upper layer, with a dosage of 250 kg per mu.
(2) Colonization
Planting density: grapefruit grows vigorously and has a large crown. Grafted trees will 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. Allocating pollination trees: Grapefruit has strong fruit-bearing ability, but cross-pollination can improve the fruit-setting rate and increase the fruit, so it should be planted in a single-row mixed way. Planting time: Grapefruit can be planted in spring (March) and autumn (165438+1October), preferably in the first half of March. Planting should be carried out on cloudy or sunny nights, not suitable for planting in rainy days or when the soil is too wet.
fertilize the soil or land
（ 1）
Fruitless young roots have shallow distribution and weak ability to absorb fertilizer, so we should master the principle of giving attention to both fertilizer and water and applying thin fertilizer frequently. Fertilize every month in March-July and June 1 time. Among them, spring shoot fertilizer in March, summer shoot fertilizer in May and 1 1 winter fertilizer are essential. Young trees mainly use organic nitrogen fertilizer, such as human excrement, decomposed manure and cake fertilizer, combined with 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 antifreeze.
② Fertilize 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 speaking, fertilization should be carried out at least three times a year. Germination-accelerating fertilizer: It should be applied before germination in early March 10- 15 days, with quick-acting nitrogen fertilizer as the main 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, which should be determined by the number of fruits 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 you have fewer fruits, you can consider or not to apply strong fruit fertilizer to prevent sudden autumn shoots. Fruit picking fertilizer:1applied in early October 165438+, accounting for about 40% of the whole year. The growth of grapefruit fruit consumes a lot of nutrients, so it is necessary to replenish nutrients in time, restore the tree vigor, improve the ability of cold resistance and overwintering, promote the differentiation of flower buds, and lay the foundation for the growth and fruiting in the coming year. Fruit picking fertilizer should be combined with quick-acting fertilizer and organic fertilizer, combined with 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 demand of trees for nitrogen, phosphorus and potassium in time.
③ plastic trimming
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, it should be topped 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 get sufficient light. Always wipe off branches and branches that cross, overlap and disturb the tree shape, as well as 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, only long branches, pests and diseases, dead branches, too dense and weak branches are left. Improper positioning should be thinned out, and more internal branches should be left. As a result, 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 backbone 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, short and dense, upright branches and lateral branches should be sparse, and drooping branches and weak branches should be kept 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 left.
3. Renewal of old trees
The best time for the 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 when they are updated, and the main branches and auxiliary branches should be kept when they are updated. All the 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. COVID-19 can be formed and fruits can be restored within 1-2 years after germination and shoot control. For some rotten branches that still have the ability to bear fruit, a part can be updated every year through rotation, and the whole tree will be updated within 2-3 years.
(4) pest control
1. Main diseases of grapefruit
The main diseases of grapefruit are Huanglongbing, canker, scab and anthracnose, and the control methods are the same as those of citrus, which can be used for reference. Ulcer is very harmful to grapefruit. Canker disease is caused by bacteria, which mainly attacks new shoots, young leaves and young fruits, forming ulceration spots with rough surface, brown color and 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 nursery, cutting nursery and seedling base are established to prevent sick seedlings from coming out of the nursery. Comprehensive measures should be taken to prevent and control the application of diseases in gardens.
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, fully spray the mixture of stone and sulfur to eliminate the source of overwintering disease.
(2) Prevent and control pests infecting the disease source in time at all stages of bamboo shoot harvesting. Such as leaf miner and malignant leaf worms.
(3) Spray the medicine every time the new bud is exposed (before self-cutting) and every 10, 30 days and 50 days after the flower withers. Optional drugs include 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 red spider, rust tick and other mites, scale insects such as arrowhead scale and brown spot scale, citrus leaf miner and biting insect.
Control method of harmful mites: spraying 73% propargite EC with 2000-4000 times, 50% cyfluconazole 1500-2000 times and 20% dicofol EC with 800- 1000 times; Control method: 40% omethoate EC 1000 times solution and 20% fenvalerate EC 3000 times solution 1-2 times solution can be sprayed 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 are 0.5-10 cm long. The dead bark of the trunk can be scraped off before the insects leave the hole in the adult emergence stage, and 40% dimethoate 1: 1 emulsifiable concentrate and kerosene can be applied to the damaged parts. At the peak of adult emergence, 80% dichlorvos EC 1000 times or 90% trichlorfon 1000-6544 times can be used.