Sweet potatoes are a rewarding and resilient crop, popular on dinner tables and valuable for farmers. But moving from a few plants in the garden to a full-hectare crop requires a solid plan.
Based on a detailed production guide from Windmill (Pvt.) Ltd., here’s a breakdown of the key requirements and considerations for successfully growing one hectare (about 2.47 acres) of sweet potatoes.
Disclaimer: This guide is based on a document from March 2014. While the agricultural principles remain sound, specific product names, availability, and especially costs will have changed. Always consult with your local agricultural extension office for a plan tailored to your area.
Step 1: Site Selection and Preparation
Getting the foundation right is the most critical step. Sweet potatoes have specific preferences for where and how they grow.
- Soil: They thrive in sandier, well-drained soils. Heavy, clay-like soils can lead to poor tuber formation and waterlogging, which the plants hate.
- Planting on Ridges: To ensure excellent drainage and make harvesting easier, it's recommended to plant sweet potatoes on raised ridges or mounds.
- Spacing:
- Between rows: 1.0 to 1.5 meters.
- Within rows: 250 to 600 mm (25 to 60 cm) between plants.
- This spacing gives the vines room to spread and the tubers space to develop underground.
Step 2: Planting and Timing
Timing is everything in farming. Sweet potatoes need warmth to mature properly.
- Planting Date: Plant as soon as the danger of frost has passed.
- Maturity: The crop requires approximately 120 frost-free days to reach maturity.
- Planting Material: Sweet potatoes are grown from "slips," which are 300-400 mm sections of vine from a previous, healthy crop. It's crucial to use slips that are free from disease and viruses to ensure a healthy start.
Step 3: Preparing Your Slips (Seedbeds)
Before you plant in the main field, you need to cultivate enough slips. The guide suggests you'll need about 400 kg of root stock to produce enough slips for one hectare. These roots are planted close together in a "seedbed" to sprout the vines.
To protect these valuable starter plants from soil-borne pests like eelworm, the guide recommends fumigating the seedbed site before planting. Two options mentioned were:
- Basamid granules: Broadcasted evenly over the bed.
- EDB Tech: Applied in rows.
Step 4: Fertilization Strategy
Proper nutrition ensures you get plenty of large, healthy sweet potatoes instead of just a field of green leaves. The guide offers two main fertilization plans, both involving a two-part application.
Important Note: Applying too much nitrogen early on will cause the plant to focus on growing leaves ("excessive vegetative growth") at the expense of the tubers. The guide also recommends using a fertilizer that contains Boron.
Option 1:
- Base Dressing (at planting): 300 kg/ha of Compound C (5:15:12).
- Top Dressing (3-4 weeks later): 100 kg/ha of AN (34.5% N).
Option 2:
- Base Dressing (at planting): 300 kg/ha of Compound L (4:17:11).
- Top Dressing (3-4 weeks later): 100 kg/ha of AN (34.5% N).
Step 5: Pest and Weed Control in the Main Field
Once your slips are planted in the field ("lands"), you need to protect them from pests and weeds.
- Eelworm: This persistent pest can be managed with EDB Tech applied at the planting station or through good crop rotation.
- Grasses: An herbicide like Agil 100 EC can be used to control grasses after they emerge.
- Leaf Eaters: Pests that chew on the leaves can be controlled with a product like Carbaryl 85. The guide suggests adding 5% molasses to the spray mix, which can help it stick to the leaves and act as an attractant.
- Weevils: These pests cause significant damage, especially in heavier soils. The best defense is good hygiene (removing old plant material) and crop rotation.
A Note on Costs from 2014
To give a historical perspective, the 2014 guide listed the following costs. These are for reference only and are not current.
- Basamid granules: $13/kg
- EDB Tech: $380 per 20-liter container
- Agil 100 EC: $22/liter
- Carbaryl 85: $10/kg
Always get current quotes from local suppliers for your budgeting.
Final, Crucial Advice
The guide ends with two vital pieces of information:
- A 15-liter knapsack sprayer is a common tool for application. It would take about 17 full knapsacks to cover a hectare.
- FOR FURTHER DETAILS, ALWAYS READ AND UNDERSTAND THE LABELS. This cannot be overstated. Product labels contain critical information on safety, application rates, and usage.
Growing sweet potatoes on a larger scale is a manageable and profitable venture with the right knowledge and planning. Good luck, and happy farming