Germination temperature
Soil at least 15 °C (59 °F); best 25-35 °C (77-95 °F).
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Bitter melon is a fast, warm-season climbing vine. Soak the hard seed, sow it in warm soil and give the vines a strong trellis for straight fruit and easy picking.
Soil at least 15 °C (59 °F); best 25-35 °C (77-95 °F).
About 2-3 cm (1 in).
Slow and uneven in cool or dry soil; thin about 15 days after sowing.
Full sun.
Soak seed for about 24 hours.
Either: direct sow, or transplant 15-day to 5-week-old seedlings.
Bitter melon seed has a stiff coat and germinates poorly in cool, dry soil. In India seed is often treated with Trichoderma viride (4 g per kg) or Pseudomonas fluorescens (10 g per kg) against soil-borne disease.
Helpful. Ontario's specialty crop guide lists soaking and scarification for best germination; lightly nicking the hard coat lets water in faster, but a good soak is usually enough.
Not needed. Bitter melon is a tropical, frost-tender crop.
Soak seed in water for about 24 hours before sowing. In trials at Punjab Agricultural University, a 24-hour soak followed by 24-48 hours in moist sacking gave faster, more even emergence in cool winter sowings.
Seed needs warm, moist soil: at least 15 °C (59 °F), ideally 25-35 °C (77-95 °F). Plants grow best at air temperatures of 24-27 °C (75-81 °F) and are killed by frost.
About 2-3 cm (1 in) deep in moist, warm soil.
Well-drained sandy loam rich in organic matter, pH 6.5-7.5. TNAU prepares pits 30 cm (12 in) wide and deep filled with manure-enriched soil.
Water the pit before sowing and keep the soil moist but not waterlogged until seedlings appear.
Seed germinates under its soil cover; grow the vines in full sun.
Germination can be slow and patchy if the soil is cool or dry. In warm soil TNAU thins seedlings 15 days after sowing.
To get an earlier crop, sow one or two soaked seeds in 10 x 10 cm (4 x 4 in) polythene bags or pots. TNAU transplants 15-day-old seedlings; in cooler climates transplants are set out 3-5 weeks after sowing, after the last frost.
TNAU spaces pits 2 x 1.5 m (6.5 x 5 ft) and keeps two plants per pit; Ontario field growers use 40-50 cm (16-20 in) between plants in rows 1.2-1.5 m (4-5 ft) apart on a trellis.
Give each plant a stake to reach the pandal or trellis, about 2 m (6 ft) high. Irrigate once a week and keep weeds down while vines establish.
Cause: hard seed coat and cool or dry soil. Fix: soak seed for 24 hours and sow only when the soil is above 15 °C (59 °F), ideally 25 °C (77 °F) or warmer.
Cause: melon fruit fly (Bactrocera cucurbitae). Fix: pick fruit young and often, remove and destroy infested fruit, and follow local extension advice.
Cause: powdery or downy mildew. Fix: give vines air on a trellis and treat early; do not use sulphur or copper dusts, which TNAU warns are toxic to bitter gourd.
Cause: fruit left too long on the vine. Fix: harvest every few days while fruit is firm and green.
Cause: vines sprawling on the ground. Fix: grow on a trellis about 2 m (6 ft) high, which keeps fruit clean and raises yield.
TNAU lists CO 1, MDU 1, Arka Harit, Priya and Preethi for Tamil Nadu, plus the hybrid COBgoH 1.
Mix about 10 kg of well-rotted manure into each pit before sowing and top-dress with a little nitrogen about 30 days after sowing.
First fruit is usually ready 50-90 days after sowing depending on variety and climate; picking every few days keeps the vine fruiting for many weeks.
Bitter melon can spread from dropped seed; UF/IFAS lists it as 'manage to prevent escape' in Florida. Do not let ripe fruit split on the vine.
Soak bitter melon seeds, sow them in warm soil and train the vines up a trellis for a long picking season.
Yes. The seed coat is stiff, so a 24-hour soak helps the seed take up water and germinate faster and more evenly, especially in cool weather.
Yes, for good yields. A trellis or pandal about 2 m (6 ft) high keeps fruit straight and clean and makes picking easier.
While the fruit is firm and green or just turning pale. Ripe orange fruit splits open and is no longer used as a vegetable.