Effective Nursery Preparation Techniques for Tasar Food Plants

Tasar silk production begins long before the silkworms start feeding. It starts in the nursery – where seeds of host plants like Terminalia arjuna (Arjun) and Terminalia tomentosa (Asan) are carefully germinated and raised into healthy seedlings. A well-prepared nursery is the foundation of a productive tasar plantation. Get this step wrong, and you’ll face weak seedlings, poor survival rates, and delayed establishment of your rearing field. This post walks you through every critical aspect of nursery preparation for tasar food plants, from site selection to seedling care before transplantation.

Why nursery raising matters in tasar sericulture 🔗

In the wild, tasar food plants grow as tall, irregularly distributed trees in forests and along paddy field bunds. This makes silkworm rearing difficult and leads to high larval mortality from pests and diseases, especially during the early instars. Systematic nursery-raised plantations solve this problem by producing uniform, healthy seedlings that can be transplanted into well-managed fields.

While tasar food plants can technically be propagated by direct sowing, the current recommended practice is to first raise seedlings in a nursery and then transplant them to the field. This approach reduces the establishment period, saves valuable seed material, and significantly improves seedling survival rates. The nursery phase typically lasts about 2.5 to 3 months, during which seedlings develop strong root systems and sturdy stems before facing field conditions.

Selecting the right site for your nursery 🔗

The nursery site is perhaps the most critical decision in the entire process. A poor location will undermine every other effort you make. According to research published in Plant Archives by the Basic Tasar Silkworm Seed Organization (BTSSO) under the Central Silk Board, the nursery should always be set up on high and dry land that is free from waterlogging.

Waterlogging is the biggest enemy of tasar seedlings. Excess moisture around the root zone encourages fungal diseases, root rot, and poor aeration – all of which can kill young seedlings quickly. Choosing elevated terrain ensures natural drainage of rainwater and prevents water from pooling around the seed beds.

Shade and protection requirements 🔗

Tasar seedlings need proper shade during their early growth phase. The nursery site should ideally be located under partial tree cover or fitted with artificial shade structures. Seedlings must be maintained under shade conditions for at least 2.5 to 3 months, with a relative humidity above 50%. Direct, intense sunlight can desiccate tender seedlings and scorch young leaves, so controlled light exposure is essential.

Additionally, the site should be fenced or protected from stray animals, which can damage seedlings and disturb seed beds. Protection from strong winds is also important, especially for very young seedlings that haven’t yet developed strong stems.

Proximity to a water source 🔗

A dependable water source near the nursery is non-negotiable. Even though tasar food plants are generally rainfed and adapted to submarginal soils, seedlings in the nursery need consistent moisture for proper germination and early growth. Whether it’s a shallow well, a pond, or a canal, having water close by allows for timely irrigation, especially during dry spells between monsoon showers. Basin irrigation or watering with a rose can is typically used in tasar nurseries.

Soil preparation and enrichment 🔗

The soil mix used in the nursery is not ordinary field soil. It needs to be carefully formulated to provide the right balance of nutrients, drainage, and moisture retention for germinating seeds and young roots.

The ideal soil mixture 🔗

For raising Arjun (T. arjuna) seedlings, the recommended soil mixture ratio is Farm Yard Manure (FYM) : Soil : Sand = 3:2:1. For Asan (T. tomentosa), the ratio shifts to 1:3:1, as per the nursery raising guidelines published by BTSSO, Central Silk Board. The FYM component provides essential nutrients and improves soil structure, while sand ensures good drainage and prevents compaction.

Before mixing, make sure the cow dung or FYM is well decomposed. Fresh, undecomposed manure can generate heat during further decomposition and burn delicate roots. It can also harbour weed seeds and pathogens. Decomposed FYM, on the other hand, has a crumbly texture, a mild earthy smell, and is rich in beneficial microorganisms.

Insecticide treatment of soil 🔗

Soil-borne pests – particularly termites – are a serious threat to tasar seedlings. Termites can destroy root systems and kill seedlings before they even emerge above ground. To prevent this, the nursery soil is treated with insecticides such as Phorate (Forate) granules, which are mixed thoroughly into the soil before filling the seed beds or polythene tubes.

The soil, manure, and insecticide must be mixed thoroughly to ensure even distribution. Patchy application can leave pockets where pests survive and attack vulnerable roots. Some practitioners also use Aldrin 5% dust as an alternative soil treatment. The key is to create a pest-free growing medium that gives seedlings the best possible start.

Preparing nursery beds 🔗

Once the site is selected and the soil mixture is ready, the next step is constructing the actual seed beds where seeds will be sown.

Bed dimensions and layout 🔗

Nursery beds should be of convenient and manageable size – typically about 1 to 1.5 metres wide and 3 to 5 metres long. The width is kept narrow so that a person can easily reach the centre of the bed from either side without stepping on the soil, which would cause compaction. Raised beds (about 15 cm above ground level) are preferred because they provide excellent drainage and prevent waterlogging during the rainy season.

A gap of about 30 to 40 cm should be maintained between adjacent beds. This space serves as a pathway for carrying out nursery operations like watering, weeding, and inspecting seedlings without disturbing the beds.

Seed sowing in beds 🔗

Seeds are sown in lines within the prepared beds, maintaining a spacing of approximately 15 cm between rows and 15 cm between individual seeds, at a depth of about 2 cm. This spacing allows each seedling adequate room for root and shoot development without excessive competition for light, water, and nutrients.

Under normal conditions, germination begins about 4 weeks after sowing. Each seed typically produces one seedling, although polyembryonate seedlings (twins or triplets from a single seed) have been observed occasionally. These are rare and don’t significantly affect overall nursery management.

Seed collection and pre-sowing treatment 🔗

Good seedlings start with good seeds. Mature, ripened seeds of Arjun and Asan are collected from healthy parent trees before natural shedding, usually during April to May. Seeds that have already fallen to the ground may have reduced viability or could be damaged by insects.

Soaking to soften the seed coat 🔗

Tasar food plant seeds have a hard outer coat that can delay or inhibit germination. To overcome this dormancy, seeds are soaked in plain water – 96 hours for Arjun and 48 hours for Asan. This soaking softens the seed coat and allows water to penetrate, triggering the germination process.

After soaking, the seeds are removed from the water (often stored in gunny bags during soaking), heaped under tree shade, and covered with wet gunny cloth or bags. Regular sprinkling of water maintains the humidity around the seed heap. An ideal heap size is 1,500 to 2,000 seeds. Within about a week, germination begins and the seeds are ready for sowing in prepared beds or polythene tubes.

Raising seedlings in polythene tubes 🔗

In addition to open seed beds, tasar seedlings can also be raised in polythene tubes. This method offers a significant advantage: it minimises root disturbance during transplantation. When seedlings grown in open beds are uprooted for transplanting, some root damage is inevitable. Polythene tube-raised seedlings, however, can be moved to the field with their entire root ball intact.

The tubes are filled with the same enriched soil mixture (FYM, soil, and sand in the appropriate ratio) and one germinated seed is placed in each tube. The tubes are arranged in the nursery under shade and watered regularly. Before transplanting, it is advisable to water the seedlings thoroughly a day before removal to loosen the soil and make extraction easier.

Caring for seedlings in the nursery 🔗

Once germination occurs, the real work of seedling care begins. The goal is to produce vigorous, healthy seedlings that can withstand the stress of transplantation and establish themselves quickly in the field.

Watering and irrigation 🔗

Consistent moisture is critical. The nursery beds should never be allowed to dry out completely, nor should they become waterlogged. Light, frequent watering using a rose can or gentle sprinkler is ideal. During hot, dry periods, watering may need to be done twice daily – early morning and late afternoon. The proximity of the nursery to a water source makes this task much more practical.

Weeding and pest monitoring 🔗

Weeds compete with young seedlings for nutrients, water, and light. Regular hand weeding should be done carefully to avoid disturbing the shallow roots of tasar seedlings. Pest monitoring is equally important. Look for signs of termite attack (wilting seedlings with damaged roots), caterpillar feeding (holes in leaves), and fungal diseases (spots or discoloration on leaves and stems). Early detection allows for prompt treatment before significant damage occurs.

Duration and readiness for transplanting 🔗

Seedlings are typically maintained in the nursery for about 3 months until they reach a height of approximately one foot (30 cm) in the case of bed-raised seedlings. For longer nursery periods (up to one year), seedlings can grow to about 1.50 metres in height, which is the preferred size for transplantation into the main field. The ideal transplanting window is the monsoon season, from June to September, when natural rainfall supports establishment and reduces the need for manual irrigation.

When the seedlings are ready, they are carefully removed and transplanted into pre-prepared pits in the plantation site. These pits (typically 1 ft × 1 ft × 1 ft) are filled with a mixture of soil, FYM or compost, karanj cake, bone meal, wood ash, and insecticide dust. The transplanted seedlings then take another 3 to 4 years to become suitable for tasar silkworm rearing.

Common mistakes to avoid in nursery preparation 🔗

Choosing low-lying land: This is the most frequent mistake. Low-lying areas collect water during rains and create the waterlogged conditions that kill tasar seedlings. Always pick elevated, well-drained land.

Using fresh (undecomposed) manure: Fresh cow dung generates heat and can harbour pathogens. Only well-decomposed FYM should be used in the soil mix.

Skipping insecticide treatment: Termites and other soil pests are nearly invisible until the damage is done. Treating the soil with appropriate insecticides before sowing is a preventive step that should never be skipped.

Overcrowding seeds: Sowing seeds too close together leads to weak, spindly seedlings that compete for resources. Maintain the recommended 15 cm spacing in both directions.

Neglecting shade: Exposing young seedlings to direct, harsh sunlight causes leaf burn and dehydration. Maintaining proper shade for the entire nursery period is essential for producing robust seedlings.

The bigger picture: nursery quality and plantation success 🔗

The quality of your tasar plantation is directly determined by the quality of your nursery. A well-managed nursery produces seedlings with strong root systems, healthy foliage, and the vigour needed to survive transplantation and field conditions. According to the Central Silk Board’s research on host plant management strategies, the adoption of proper nursery raising techniques is one of the key factors in improving tasar silk productivity and achieving national production targets.

Tasar sericulture provides livelihoods to hundreds of thousands of tribal and rural families across central India. The difference between a productive plantation yielding quality cocoons and a struggling one often traces back to how well the nursery was set up. Every step – from selecting the right land to mixing the right soil to timing the seed collection – plays a role in the final outcome.

What do you think? If you’re involved in tasar sericulture, what challenges have you faced during nursery preparation – is it the site selection, soil quality, or pest management that proves most difficult? And do you think polythene tube seedlings offer a clear advantage over open bed-raised seedlings for your local conditions?

References

1. https://silks.csb.gov.in/lalitpur/food-plant-production-technology-of-tropical-tasar/
2. https://silks.csb.gov.in/sundargarh/tasar-food-plant-production-technology/
3. https://www.plantarchives.org/SI%20VSOG/2.pdf
4. https://silks.csb.gov.in/golaghat/food-plant-production-technology-of-tropical-tasar/
5. https://plantwiseplusknowledgebank.org/doi/full/10.1079/pwkb.20197800170
6. https://hbmahesh.weebly.com/uploads/3/4/2/2/3422804/non_mulberry_food_plant_cultivation..pdf
7. https://apps.worldagroforestry.org/treedb2/speciesprofile.php?Spid=18136