High-Tech Nursery Establishment
It is conventional method of establishing nursery in open field. Seedlings developed by this method are destroyed by diseases, pest or extreme cold & heat injury sometimes which make yield much lesser than expectation. Due to higher prone of vegetables towards biotic or abiotic diseases & pest attack with higher price of seed these days, conventional method of nursery are very risky methods for seedling development. In developed countries, due to controlled nursery management, 100% seed germination along with disease & pest attack free seedlings are being produced. So, in country like Nepal also, controlled house must be constructed to raise nursery where soilless medium is used, disease, pest management, well manuring & hardening is done.
High Tech Nursery:
Protective of Controlled House:
Controlled environment means area with protecting seedlings from unconditional or unfavorable environment all round year & producing healthy seedlings which use net for controlling insect-pests. Integrated crop production & integrated disease & pest management system is applied for crop protection along with regulated sunlight, water, manuring & temperature for the nursery seedlings.
Seedlings developing mediums:
It is found in seas & ocean which is rapidly growing partially decayed plant part which have high water infiltration & drainage capacity. It is found as peat in the market.
It is of coconut tree which is like beehive fibrous in nature having good aeration capacity, water drainage, with moisture retention capacity, free of harmful bacteria used in seedling raising.
Perlite is greyish white substance coming from volcanic eruption mixed with silica having neutral pH. It is free from harmful pathogens & is good medium for growing seedlings in nursery.
Alkali metals like Calcium, Magnesium, Potassium & Iron rich medium with high holding capacity free from harmful pests & bacteria; medium to raise seedlings.
Powder made by burning Igneous rock & lime which is soft with good aeration, water holding capacity & free of harmful bacteria & pathogens widely used as medium for growing seedlings.
Seedlings development in equal sized plastic trays is considered good. According to size of vegetable seed, different sized plastic tray or mud tray can be used for growing seedlings. Soilless medium is kept in these trays. Planting in this way makes much easier to look after seedlings.
Points to remember during raising seedlings through high-tech nursery:
- Use of improved & healthy seed:
Seed with true to varietal characteristics must be purchased or bought from the faithful or trustworthy source. Purchased seed must be carefully stored during the storage period. Do not maintain seed from the crop grown from your own field. At most buy the seed which are treated with Captan or Thiram @ 2-3 gram / kg of seed before buying.
- Use of clean tray:
Before using tray for seedling raising, they must be sanitized with 1% chlorine water & make proper drying. Dipping in potassium solution also can make it free from germs or bacteria.
- Tray size:
Use appropriately sized tray for raising seedlings. It entirely depends upon seed size. Use small sized for small sized seed whereas use large sized tray for large seeds.
- Preparation of Medium:
Mix 3 parts of coco-peat, 1 part of perlite & 1 part of vermiculite properly which can be used for growing seedlings.
- Maintaining pH level:
The pH of such prepared medium must be 5.5-6.5 which enables seedlings to draw more nutrients from soil. If pH is more acidic add lime to neutralize the medium pH without adding soil.
- Filling tray:
Tray must be properly filled. Nowadays, tray is being filled with machine.
- Seed planting:
Plant single seed just at center of tray 1.5 cm below the medium surface.
During irrigation, consider medium used, environment condition & air flow however, completely irrigate the tray for sufficient moisture. No need of irrigation during rainy days.
- Manuring through irrigation:
Apply 100-200 ppm or 1-2 grams nitrogen or 2-4 grams urea in 10 liters water & spray in the tray. It depends upon seed type. It is also called fertigation i.e supplying fertilizer in form of solution dissolving in water to the plants or seedlings. It ensures uniform distribution of nutrition to the seedlings.
Before transplanting seedlings, avoid irrigation 4-5 days before transplanting. Adjusting house temperature by lowering it can also helps in hardening seedlings. Exposure to the full sunlight also helps in hardening. Similarly, removal of all the shedding nets, polythene sheets etc can also be useful in hardening.
Disease like damping off in nursery will be very less if air flow in nursery is better. Treated seed also prevent this disease. If this disease happens to attack, spray Captan or Bavistin @ 2 gram & 1 gram respectively in 1 liter of water.
It may be pre-emergence or post emergence damping off. It can be controlled by following ways:
- collect the seeds from disease free plants.
- Avoid overcrowding and heavy application of nitrogenous fertilizers.
- use raised beds and reduce water logging conditions.
- soil treatment with 2.5% Formalin solution fortnight before sowing.
- Hot water treatment of seeds.
- Application of Biocare-B, Biocare-F @ 2g/liter of spray.
- use of seed protectants, Captan, Thiram, Carbendazim @ 2-3 gram/kg of seed to protect pre-emergence damping off.
- spray 4% neem seed kernel extract on the plants.
- Spray malathion 1.5 ml/liter of water.
Leaf Curl Virus:
- Treat the soil of the nursery by furadon at 3-5 gram/ square meter.
- Spray the nursery beds 15 days before after seed germination at 7 days interval with Malathion @ 1.5 ml/liter of water. Last spray is done 2 days before transplanting.
- Remove the infected plants if any in the field and bury or burn them properly.
Temperature requirement for seed germination & seedlings development of different vegetable crop are tabulated below:
|S.N.||Vegetable||Germination||Day temperature for seedling growth||Night temperature for seedling growth|