How to Grow Okra in Australia

Okra (Abelmoschus esculentus) is a frost-tender annual in the mallow family, Malvaceae, grown for its young, ridged seed pods. It crops through the peak of summer, when heat has stopped many other vegetables, from the Top End dry season to a Brisbane January. The mistake most gardeners make is leaving pods on the plant too long.

Three mistakes that matter

1. Sowing into cold soil. Seed germinates poorly or not at all in cool ground, and cold, wet soil slows young plants. Wait for the soil temperature in When to plant, or start seed in cells somewhere warm.
2. Letting pods grow too big. Pods turn woody fast, and pods left to mature on the plant slow the setting of new ones. Pick every two or three days, at the size given in Harvesting Pods.
3. Feeding too much nitrogen. Rich, nitrogen-heavy feeding builds a tall, leafy plant that sets few pods. Go light on nitrogen and shift to potassium from first flowers, as Care by growth stage sets out.

When to plant

Soil warmth decides the date: sow once the soil holds at least 20°C at sowing depth and frost has passed. Seed germinates best between 20 and 35°C, and not at all below about 17°C. Nights also need to stay above about 13°C for steady growth. One sowing is usually enough, because a plant that is picked often keeps flowering and setting pods until the weather cools.

At the cool edge of a window, start seed on a seedling heat mat and plant out once the soil warms. At the late edge, sow a compact, quick variety such as 'Dwarf Long Pod' or 'Greenish 351'.

Site, soil and setup

Rotate beds: do not follow okra with tomato, capsicum or eggplant, which share root-knot nematode (Meloidogyne species), while sweet corn, onions and cabbage resist it.

Container growing

A compact variety crops well in a pot: grow one plant per pot of at least 20 to 25 L and about 30 cm across. Use a pot with drainage holes and premium potting mix, and choose 'Dwarf Long Pod' or 'Greenish 351', which both stay compact.

• Water: check daily in hot weather and water deeply when the top few centimetres dry, since pots dry much faster than beds. See watering pots in summer.
• Feed: mix a controlled release granular for containers into the potting mix at planting, at the label rate. From first flowers, add fish and seaweed blend at 25 mL per 9 L fortnightly.
• Position: full sun, out of strong wind, where a top-heavy plant will not blow over.

Sowing Seeds

Sow soaked seed direct into warm soil where the plants will grow, or start it in cells somewhere warm and plant it out young.

Preparing the seed

Okra seed has a hard coat, so soak it in water overnight, or for up to 24 hours, before sowing. The soaked seed takes up water faster and germinates more readily. Sow it the same day, while it is still swollen, and do not let it dry out. If a root tip has already emerged, handle the seed gently so the tip does not break.

Sowing direct

• Sow two seeds per hole, 15 to 20 mm deep, at the spacing in Site, soil and setup.
• Water in, then keep the soil just moist, because heavy watering chills the soil.
• Seedlings appear in 7 to 21 days, often at about 12 to 14 days in warm soil.
• If both seeds come up, keep the stronger seedling and remove the weaker one.

Starting in cells

• Sow two or three seeds about 10 mm deep in each cell of a punnet of seed raising mix, 4 to 6 weeks ahead.
• Keep the punnet on a warm, sunny windowsill or a heat mat, and the mix moist.
• Thin to the strongest seedling in each cell.
• Harden off (accustom seedlings to sun and wind outdoors) for about a week.
• Plant out at 5 to 10 cm tall, before the taproot fills the cell, then water in and mulch with straw.

Care by growth stage

Warmth, steady water and a light hand with nitrogen decide the crop. Weeks count from sowing and vary with variety and heat.

Companion planting

Some neighbours trap or kill okra's pests, while its own mallow relatives carry pests into the bed.

Grows well with

• French marigold, planted thickly through the bed, whose roots trick root-knot nematode larvae into entering and dying before they breed.
• Sunflower, a trap crop whose flower heads draw egg-laying bollworm moths away.

Keep apart

• Hibiscus and mallow weeds, which host cotton stainers and rough bollworm (Earias huegeliana).
• Tomato, which shares cotton bollworm and root-knot nematode with okra.

Harvesting Pods

The first pods are usually ready 8 to 14 weeks after sowing, and each pod is ready 5 to 10 days after its flower opens.

• Pick most pods at 5 to 10 cm long, while they are still tender.
• Test with a knife: if the stalk is too tough to cut, the pod is probably too tough to eat.
• Cut pods off with secateurs or scissors rather than snapping them, which tears the skin at the tip.
• Pick every two or three days once cropping starts, working up the plant as pods mature from the base upwards.
• Wear gloves and long sleeves, because the fine hairs on pods and leaves irritate skin, even on near-spineless types.

Store pods unwashed in a bag in the crisper and use them within about a week, because washing speeds decay. Okra keeps best at 7 to 10°C with high humidity, so the coldest part of the fridge does not suit it. For longer keeping, freeze pods whole and uncut, and they keep for months. Cook okra in gumbo, curries, soups and stir-fries, or grill it whole.

Common problems

Seed fails to come up. Hard seed that was not soaked, or cold, wet soil, is the usual cause; see Preparing the seed and Three mistakes. Read more

Flowering stops in midsummer. In the hottest, driest spell okra can slow or stop flowering, so keep the water steady and see Tips for cutting plants back.

White powdery coating on the leaves. This is powdery mildew, most common in humid areas; at the first spots, spray 1 part full-cream milk to 10 parts water. Read more

Pests and diseases

Okra shares many pests with cotton and hibiscus, its mallow relatives, and any spray used must name okra or fruiting vegetables on its label.

Cotton bollworm (Helicoverpa armigera). Caterpillars feed on buds, flowers and young pods, and damaged buds often drop. Native budworm (Helicoverpa punctigera) looks alike and is managed the same way. Squash eggs and young caterpillars and bin bored pods. For heavier attack, spray a Bt (Bacillus thuringiensis) product while caterpillars are under 7 mm long.

Cotton aphid (Aphis gossypii). Small aphids, from yellow to dark green or dull black, cluster under young leaves and on shoots and buds. Heavy colonies curl and wrinkle new leaves, and their sticky honeydew grows sooty mould. Hose them off or spray insecticidal soap, and leave ladybirds, lacewings and hoverflies to feed. Read more

Two-spotted mite (Tetranychus urticae). White to pale yellow speckling spreads along the leaf veins, with fine webbing underneath, and numbers climb fast in hot, dry weather. Spray leaf undersides with water, and avoid broad-spectrum sprays that kill the predators that eat mites. Read more

Pale cotton stainer (Dysdercus sidae). These bugs, about 12 mm long, suck the developing seeds inside the pods, which can leave small, dark, raised spots on the pods. Hand-pick them, and clear mallow weeds and old plants from around the bed.

Root-knot nematode (Meloidogyne species). These microscopic soil worms cause galls (swellings) on the roots, leaving plants stunted, yellow and quick to wilt, and okra is sensitive to them. They thrive in warm, sandy soil. Bin affected plants rather than composting them, rotate beds as Site, soil and setup describes, and keep the soil rich in compost. Read more

Cercospora leaf spot (Cercospora species). A sooty to dark olive mould grows on the undersides of okra leaves, which then roll, wilt and fall. The spores spread in wind, rain and irrigation and carry over on crop debris. Water the soil rather than the leaves, and clear old plants away.

Prevention first

• Pull out old plants at the end of the season, bin any with galled roots, and rotate beds.
• Keep mallow weeds and self-sown okra out of the patch, since they carry stainers and bollworms between crops.
• Check buds, pods and leaf undersides twice a week, and act on the first eggs, colonies or speckling.
• Spare the bees: if you must use pyrethrum, spray late in the day, away from open flowers.

Tips

1. When heat stalls flowering, cut the stems back to 15 to 30 cm above the soil and water well. Feed fish and seaweed blend at 25 mL per 9 L fortnightly, and plants usually regrow and flower again as the weather eases.
2. To keep okra from turning slimy, pick pods young, dry them well after washing, and cook them in small batches over high heat.
3. 'Red Burgundy' pods turn green in the pan, which is normal and no sign of a poor pod.
4. To save seed, grow a single variety, because insects often cross okra flowers, so seed saved from 'Heirloom Mix' will not come true. Leave a few pods on healthy plants until brown and dry, and pick them before they split. Stored cool and dry, the seed keeps at least three years.