Nursery Management: Foundation of Successful Vegetable Production System
Dr. Deepali Tewari, GBPUAT
As we say "Success of any production system depends on the kind of seed we are sowing", so is true with seedlings. Healthy seedlings grown in a well managed nursery will decide the yield and consequently the profit.
Definition of Nursery: "A vegetable nursery is a place or an establishment for raising or handling of young vegetable seedlings until they are ready for more permanent planting."
Why do we need Nursery?
Some vegetables require special cares during their early growth period. There are some vegetables with very small sized seeds. These are first sown in the nursery for better care and to combat with the time for field preparation and after about one month of seed sowing, transplanted in the main field.
These vegetables are:
- Knol-khol (kohl rabi),
- Chinese cabbage,
- Brussels sprouts,
- Sprouting broccoli,
- Chicory (red and green),
Advantages of Nursery Management:
- It is possible to provide favourable growth conditions i.e. germination as well as growth
- Better care of younger plants as it is easy to look after nursery in small area against pathogenic infection, pests and weeds.
- Crop grown by nursery raising is quite early and fetch higher price in the market, so economically more profitable.
- There is saving of land and labour as main fields will be occupied by the crops after 1 month. More intensive crop rotations can be followed.
- More time is available for the preparation of main field because nursery is grown separately.
- As vegetable seeds are very expensive particularly hybrids, so we can economize the seed by sowing them in the nursery.
Site Selection is the first important consideration for nursery management:
Critical points needed to be considered while selecting nursery area are:
- Area selected should be well drained, and free from water logging
- There should be proper sunlight,
- The nursery should be near the water supply so that irrigation can be easy.
- The area should be well protected from pet and wild animals
Soil and soil preparation:
- Raising of vegetable seedlings requires fertile and healthy soil.
- Preferably, the soil for nursery should be loam to sandy loam, loose and friable, rich in organic matter and well drained.
- The soil pH should be close to the neutral i.e. about 7.0
- It needs a deep cultivation of the nursery land either by soil turning plough or by spade and subsequent 2-3 hoeing with cultivator.
- After that all the clots, stones and weeds from the field should be removed and land should be leveled.
- Mix 2 kg well rotten and fine Farm yard manure/compost or leaf compost or 500 g vermi compost per square meter and mix in the soil. If the soil is heavy mix 2-3 kg sand per square meter so that the seed emergence may not be hampered.
Soil treatment: For getting healthy seedlings
For raising the healthy seedlings, soil must be treated to make it pathogen and pest free. Different methods adopted for this purpose are:
Treatment of soil against pathogens:
A. Soil solarization
- Suitable Time Period:May-June as temperature rises up to 45oC at this time.
- Wet the soil with water, or saturate it with water
- Spread white polythene of 200 gauges on the whole nursery area for about 5-6 weeks.
- The margin of the polythene should be covered by wet soil (compressed mud) to check the entry of air.
- After 5-6 weeks remove the polythene sheet
- Prepare the beds for seed sowing.
B Formalin Solution treatment:
Formalin dust treatment
- This treatment should be done 15-20 days before seed sowing.
- Prepare formalin solution (1.5 to 2%) in one container and drench the soil @ 4-5 litre of water per square meter soil surface to saturate it up to a depth of 15-20 cm.
- Cover the drench area with polythene sheet of 200 gauge.
- Put the wet soil on the margin of the covered polythene sheet so as it does not allow the polythene film blown away by the wind and air from the covered area to out side.
- Removes the cover (polythene) after 15 days.
- Prepare the beds for seed sowing.
C Application of fungicides:
- Generally used fungicides: Captan, Thiram which kill the soil borne pathogens.
- Use 5-6 g of any of the fungicides per square meter nursery area.
D Insect Control:
- Reason of such application: Presence of certain insect pest and their egg or secondary stage insects present in the soil which can infect the seedlings in the later stage.
- To save the seedlings against them, some insecticides are also used as soil treatment. Recommended insecticide is Chlorpyriphos @ 2 ml/ liter of water.
- depth of 15 to 20 cm in the nursery soil and then prepared the beds for seed sowing.
E. Steam treatment:
- Hot steam can be used to treat the soil against harmful insect pest.
- For this, cover the required area with the help of polythene sheet and stop the movement of air in the covered area.
- Supply the hot steam for at least 4-6 hours continuously.
- This way all the harmful pathogen and insect pest will be killed.
Nursery bed preparation
- Nursery bed should be prepared according to the season and crop.
- In the rainy season raised beds are prepared but in the winter and summer season flat beds should be prepared. Similarly onion in the Rabi season requires flat beds. For the uniform and high percentage of germination the soil must be fine and moist enough.
- If the seedlings are to be raised in boxes during unfavourable weather condition, the flower pots, polythene bags, potting plugs, wooden treys, earthen pots etc. may be used. Prepare soil mixture in the ratio of 1:1:1 of soil, sand and well rotten FYM/leaf mould etc. and fill the mixture in these seedlings raising structure. Arrangement should be made to drain excess water from these structures by making a hole in the bottom of all types of pots.
Raised nursery beds
- Length of the bed may be kept 3 to 5 meter; however, width is restricted to 1 meter only which facilitates intercultural operations.
- The beds are raised 15 to 20 cm high from the ground level. A space of 30 - 40 cm is leaft in between two beds.
- The space between two beds helps in weeding, nursery care against diseases and insect pest and also for draining out the excess rain water from the nursery beds.
- The number of beds depends on the particular crop, season and growing area of crop.
- The beds should be prepared in the east and west direction and line should be made from north to south direction on the beds.
Sowing of seeds in the nursery
After the seed bed preparation seeds are sown in the nursery bed either by broadcasting or in lines depending upon the nature and season of crop.
•· Broad casting method: In broadcasting method seeds are broadcasted on the well prepared nursery beds and later on the seeds are covered with well rotten fine sieved and treated FYM or compost.
- The major disadvantages of this method are:
- Uneven distribution of seeds in the nursery beds.
- Growth and development of seedlings is poor.
- Some times nursery becomes so dense to look like as patches of grasses. In such cases there is more possibility of damping off disease occurrence.
- Line sowing is the best method of seed sowing in nursery.
- Lines are made 0.5 to 1.0 cm deep parallel to the width at an distance of 5.0 cm from the line and seeds are sown or placed singly at a distance of about 1.0 cm apart.
- Cover the seeds with fine mixture of sand, soil and well rotten and sieved FYM or leaf compost etc. (1:1:1). After the seed covering a light irrigation must be given.
Seed covering material and its treatments
After seed sowing the seed that are sown either by broadcast method or line sowing method required cover for better emergence. Therefore, a mixture of sand: soil: FYM in the ratio of 1:1:1 is prepared, well mixed together and treated with any method of soil treatment as discussed above. It will be better to treat this mixture while treating the nursery soil. Apply 3-4 g thiram or captan per kg mixture if, it is not treated. Care should be taken that every seed is well covered by seed covering material.
Use of mulch
To maintain the soil moisture for seed germination cover the seed bed with a thin layer of mulch of paddy straw or sugar cane trash, or sarkanda or any organic mulch during hot weather and by plastic mulch (plastic sheet) in cool weather. It has following advantages:
- It maintains the soil moisture and temperature for better seed germination.
- It suppresses the weeds.
- Protects from direct sunlight and raindrops.
- Protects against bird damage.
Removal of mulch
Due attention is given to remove the covered mulch from the seedbed. After three days, observe the seed beds daily. As and when the white thread like structure is seen above the ground, remove the mulch carefully to avoid any damage to emerging plumules. Always remove mulch in the evening hours to avoid harmful effect of bright sun on newly emerging seedlings
Use of shedding net
After seed germination during the seedling growth, if there is very high temperature (> 30o C) then beds should be covered by 50% or 60% shedding nets of green/green + black coloured, about 60 - 90 cm above ground by the use of suitable support.
- The nursery beds require light irrigation with the help of rose can till the seeds get germinated.
- Excess rainwater or irrigated water should be drained out from the field as and when it is required otherwise plants may die due to excess of water.
- Watering in the beds depends upon the weather condition. If temperature is high, open irrigation is applied. Need not to irrigate the beds during rainy days.
- It is an important operation to remove weak, unhealthy, diseased, insect pests damaged and dense plants from the nursery beds keeping distance of about 0.5 to 1.0 cm from plant to plant.
- The thinning facilitates balance light and air to each and every plant. It also helps in watching the diseased and insect pest attacked plants while moving around the nursery.
- Timely weeding in nursery is very important to get healthy seedling. If there are some weeds in the seed bed, remove them manually either by hand or by hand hoe (thin forked Khurpi).
- Pre emergence herbicides can also be sprayed soon after seed sowing to control the weeds. Stomp @ 3 ml/litre of water should be sprayed on the nursery beds after the seed sowing and seed covering with mixture of FYM. soil and sand.
Adaptation of plant protection measures in the nursery against the incidence of insect pest and diseases is very important task to get the healthy seedlings. Damping off seedlings, leaf curl, leaf blight diseases and leaf miner and borer infect the seedling in the nursery. The care for controlling them time to time is essential.
- This is very serious disease of nursery.
- Pre-emergence death of seeds is seen.
- In first instance girdling takes place on the stem near base of the stem and seedlings bent down near the ground and die.
- The causal organisms are pythium, phytopthora, rhizoctonia and Fusarium fungi.
- Treat the nursery bed either by soil solarization, formalin solution or formalin dust or fungicides like thiram or captan as discussed earlier.
- Treat the seeds as discussed in seed treatment. If the disease appear after the seed emergence drench the nursery beds with 0.1% solution of brassicol or 0.7% captan or thiram after germination. It will be better to remove and burried the affected seedlings from the beds otherwise spread will be more.
The disease can be controlled to some extent by applying treated sand, soil and FYM mixture up to the level from where the seedlings are falling.
It is very small sized insect enter in the leaves from margin side and move from one place to other by eating the chlorophyll. Initially the infected part of the leaves become brown and later on dry.
- Spray 4% neem seed kernal extract on the plants (crush 40 g of neem seed kernal, add some water and allow them for overnight. In the morning filter the extract and makeup the volume 1000 ml.)
- Spray Monocrotophos or Metasystox 1.5 ml/litre of water.
• Raising of virus free seedlings
Leaf curl is a white fly transmitted viral disease, infestation starts from seedling stage and continue till harvest of the crop. The disease is specially seen in the tomato and sometime in chilli too and causes great loss of the crop.
The leaves of affected plants show curling, mottling, rolling puckering etc. It can be controlled by the following ways:
- Treat the soil of the nursery by carbofuran 3-5 g/sqm.
- Seed treatment with Imidachloprid @ 2.5 g/kg seed
- Cover the seed bed after seed sowing by Agronet making a tunnel like structure.
- Spray the nursery beds 15 days after seed germination at 7 days interval with Metasytox or Monocrotophos @ 1.5 ml/litre of water. Last spray is done 2 days before transplanting.
- Remove the infected plants if any in the field and burried in with soil or burn.
In this way the raised seedlings will be healthy and free from viral diseases.
Selection of seedlings for transplanting: After attaining proper growth, seedlings are transplanted in main field. At the time of transplanting, seedling should be:
- Stocky and sturdy
- Should have good rot system
- Should be free from any insect pests and diseases.
Hardening of the plants in the nursery
- The term hardening includes
"Any treatment that makes the tissues firm to withstand unfavourable environment like low temperature, high temperature and hot dry wind."
- Hardening is physiological process .Plants accumulate more carbohydrates reserves and produce additional quiticle on the leaves.
- In this process seedlings are given some artificial shocks at least 7-10 days before uprooting and transplanting. These shocks includes
- o Exposure to the full sunlight,
- o Removal of all the shedding nets, polythene sheets
- o Irrigation is stopped slowly and slowly.
Techniques of hardening
The hardening is done by the following ways.
- By holding the watering to the plant by 4-5 days before transplanting
- Lowering the temperature also retards the growth and adds to the hardening processes.
- By application of 4000 ppm NaCl with irrigation water or by spraying of 2000 ppm of cycocel(Chadhdha,2006).
Duration and degrees of hardening
- It is very necessary that plants should be hardened according to their kind so that there is an assurance of high percentage of survival and slow growth under the condition to be expected at the time of transplanting.
- Hardening should be gradual to prevent or check the growth.
- Warm season crops like tomato, brinjal and chillies do not favour severe hardening. In Indian condition allowing the soil to become dry for 5-6 days does the hardening.
Effect of hardening
The following effect may be observed by the hardening
- Hardening improves the quality and modifies the nature of colloids in the plant cell enabling them to resist the loss of water.
- Hardening increases the presence of dry matter and regards in the plants but decrease the percentage of freezable water and transpiration per unit area of leaf.
- Decreases the rate of growth in the plants
- Hardened plants can withstand better against unfavourable weather conditions like hot day winds or low temperature
- Hardening of the plants increases the waxy covering on the leaves of cabbage.