Sweet Potato — How to Grow Sweet Potato in Australia

☀️ Sun

Full Sun

💧 Water

Low

↔ Spacing

30cm apart

↕ Height

Up to 40cm

📅 Harvest

120 days

Growing Guide

Plant sweet potato slips (rooted cuttings) in spring (September to November) or early summer (December) once soil temperatures reach at least 18°C and all frost risk has passed — timing is crucial for a successful harvest. In tropical regions, planting can extend through summer, while subtropical gardeners should aim for late spring to maximise the growing window before cooler autumn temperatures slow growth.

Soil preparation: Sweet potatoes thrive in loose, well-draining sandy loam enriched with compost. Avoid heavy clay or overly nitrogen-rich soils, which encourage foliage at the expense of tubers. Mound soil into raised rows 20–30 cm high to improve drainage and warm the root zone.

Planting: Space slips 30–40 cm apart in rows 90 cm wide. Plant deeply, burying two-thirds of each slip to encourage strong root development.

Watering: Water consistently for the first two to three weeks while slips establish. Once growing strongly, sweet potatoes are drought-tolerant — water deeply once or twice a week during dry spells and reduce watering in the final four weeks before harvest to concentrate sugars in tubers.

Feeding: Apply a low-nitrogen, potassium-rich fertiliser at planting and again at six weeks.

Harvest: Tubers are typically ready 16–20 weeks after planting. Harvest in autumn when leaves begin to yellow. Cure tubers in a warm, humid spot for 7–10 days to harden skins and improve sweetness before storing.

🤝 Good Companions

Sweet potato grows well alongside beans corn and marigolds — beans fix nitrogen gently into the soil corn provides light vertical structure without shading the vines excessively and marigolds deter nematodes and whitefly that can damage both foliage and tubers. Nasturtiums also make a helpful companion acting as a trap crop for aphids and attracting beneficial predatory insects to the garden.

❌ Avoid Planting With

Avoid planting sweet potato near other members of the Convolvulaceae family or squash and pumpkins as these compete aggressively for the same ground-level space and soil nutrients leading to reduced yields for all plants involved. Tomatoes and potatoes should also be kept away as they share common soilborne diseases including fungal wilts that can transfer between crops.

🐛 Pests & Diseases

In Australian gardens, sweet potato weevil (Cylas formicarius) is the most serious pest, tunnelling into tubers and rendering them inedible — maintain crop rotation, destroy affected material promptly, and avoid leaving old tubers in the soil. Whitefly and aphids can attack foliage and are best managed with regular blasts of water and applications of neem oil spray. Fungal issues such as sclerotial blight thrive in humid conditions, so ensure good air circulation, avoid overhead watering, and apply a diluted seaweed solution to strengthen plant immunity.

🌱 Fertilising

At planting, incorporate a balanced slow-release fertiliser or aged compost into the mounded soil, then side-dress with a potassium-rich fertiliser such as sulphate of potash at the six-week mark to encourage strong tuber development. Avoid high-nitrogen feeds after the initial establishment phase, as excess nitrogen pushes leafy growth at the expense of the edible roots — a classic mistake in sweet potato growing.

✂️ Pruning & Training

Trim back long, wandering vines every few weeks to prevent them from re-rooting at leaf nodes away from the main plant, which can divert energy away from the primary tubers and make harvest difficult. Pinching growing tips also encourages bushier growth and helps manage the plant's spread in smaller gardens or raised beds.

🔬 Propagation

Sweet potatoes are most easily propagated from slips — shoots that sprout from a mature tuber placed in a shallow tray of water or moist sand in a warm, sunny position until roots develop, which typically takes two to three weeks. Alternatively, take 20–30 cm stem cuttings from a healthy growing vine, strip the lower leaves, and plant directly into moist, warm soil where they will root quickly and begin producing tubers within the season.

🗓 When to Plant

Spring Summer

🌾 Harvest

Autumn

🌏 Australian Climates

Tropical Subtropical

More Vegetables

Tomato → Lettuce → Broad Bean → Spinach → Garlic → Pumpkin →