How to use

Choose a bed or rectangular planter (length × width in cm) or a round pot / polybag (diameter in cm).
Pick your crop. The spacing, seeds per hole and germination rate fill in automatically — change them if your seed packet says otherwise.
For kangkung, bayam and coriander you can choose to scatter the seed and thin later, or sow in holes.
Read the number of plants and seeds to sow.

How it's calculated

Sowing in holes or transplanting (most crops)

Plants per row = length ÷ in-row spacing (rounded down), rows = width ÷ row spacing (rounded down). The calculator tries rows both ways and uses the layout that fits more plants.
Round pots: plants = pot area ÷ (in-row × row spacing), at least one plant.
Expected empty holes = plants × (1 − germination)^(seeds per hole)
Seeds = seeds per hole × (plants + expected empty holes, rounded up) — the extra is spare seed to fill gaps.

Scattering (kangkung, bayam, coriander)

Plants after thinning = area ÷ (thinning spacing)²
Seeds = plants ÷ germination × (1 + extra %) — the extra covers uneven spreading.

Default spacings are common home-garden values: for example choy sum 15 × 20 cm, pak choy 20 × 20 cm, lettuce 25 × 25 cm, chili and tomato 45 × 60 cm, brinjal 60 × 75 cm, okra and long bean 30 × 60 cm, cucumber 40 × 90 cm on a trellis. They are starting points; adjust for your variety and your space.

Worked example

A bed 120 cm × 60 cm of choy sum at 15 × 20 cm, 2 seeds per hole, 85% germination:

120 ÷ 15 = 8 plants per row, 60 ÷ 20 = 3 rows → 24 plants
Chance a hole stays empty = 0.15² = 0.0225 → 24 × 0.0225 ≈ 0.5 holes → round up to 1
Seeds = 2 × (24 + 1) = 50 seeds

The same bed scattered with kangkung, thinned to 10 cm, 85% germination and 25% extra:

7,200 cm² ÷ 100 = 72 plants
72 ÷ 0.85 × 1.25 ≈ 106 seeds

Tips

Sow small seeds (lettuce, bayam, basil) shallow — just cover them. Big seeds (long bean, okra, cucumber) go about 2 cm deep.
Choy sum, pak choy, lettuce, chili, tomato and brinjal are easier to raise in a seedling tray first and transplant at 3–4 true leaves.
Thin early. Overcrowded leafy greens stay small and get fungal problems in our humid weather.
One chili, tomato or brinjal plant needs its own pot of at least 30–35 cm across.
Sow a few seeds every 2–3 weeks instead of all at once, so you harvest steadily.
Germination rates fall as seed gets older or is kept somewhere hot. Store packets sealed in a cool, dry place.

GuidesHow to Start Vegetable Seeds at Home (Beginner's Guide for Malaysia)Sow vegetable seeds in trays at home - the right mix, sowing depth, watering, light, preventing damping-off, hardening off and transplanting.

CalculatorsPot Weight & Balcony Load CalculatorPot weight calculator for balconies and rooftops: estimate the wet weight of soil-filled pots, planters and grow bags in kg and kg per m².

FAQ

Why sow more than one seed per hole? Not every seed germinates. Two or three seeds per hole make it likely that each spot has at least one seedling. Keep the strongest and snip the others at soil level.

Why do kangkung and bayam use the scatter method? They are usually harvested young and grown close together, so scattering and thinning is quicker than making many holes. You can still sow them in holes if you prefer.

What germination rate should I enter? If you don't know, keep the default. You can test: put 10 seeds on wet tissue in a closed container and count how many sprout in a few days.

Can I plant closer than the spacing given? For leafy greens harvested young, slightly closer is fine. For fruiting crops, crowding reduces airflow and yield, so keep the full spacing.