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Protected Cultivation & Nursery Calculators

Nursery Seedling Tray Calculator

Determine the pro-trays, cells, seeds and cocopeat or perlite needed to raise seedlings for your field.

Enter your details

From the seed packet or your own test.

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%

A 98-cell tray takes roughly 2.5–3.5 L; fill one tray to check.

litres

A common mix is cocopeat, perlite and vermiculite 3:1:1 by volume (60% cocopeat).

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Please note: This calculator provides a mathematical estimate based on the values entered. Recommended agricultural application rates can vary by crop, soil, product formulation, location and official agricultural guidance. Check the product label and local agricultural recommendations before application.

Enter your field area and plant spacing, the tray size and expected germination, and get the number of pro-trays, seeds and litres of growing medium to raise enough healthy seedlings – with extra for gap filling.

About the Nursery Seedling Tray Calculator

Nursery Seedling Tray Calculator

Raising vegetable seedlings in pro-trays (plug trays) under a net or polyhouse gives uniform, disease-free plants with intact roots that establish fast after transplanting. Hybrid seed is expensive, so it pays to sow exactly what you need.

This calculator works back from the field:

  1. Plants in the field from area and spacing.

  2. Seedlings to raise – plus a margin for gap filling and culling weak plants.

  3. Cells to sow – more than the seedlings, because not every seed germinates.

  4. Trays, seeds and growing medium for that many cells.

How to use the Nursery Seedling Tray Calculator

  1. 1 Enter the field area and the spacing you will transplant at.
  2. 2 Choose the tray size and enter the expected germination.
  3. 3 Add an allowance for gap filling (10% is common).
  4. 4 Check how many litres of medium one tray takes and press Calculate.

The formula we use

Plants = Area ÷ (Row spacing × Plant spacing)
Seedlings = Plants × (1 + Extra %)
Cells = Seedlings ÷ Germination %
Trays = Cells ÷ Cells per tray, rounded up
Growing medium = Trays × Litres per tray

Worked example

Tomato for 1 acre at 90 × 60 cm, in 98-cell trays, germination 85%, 10% extra, 3 litres of medium per tray.

  1. Plants = 4,046.86 ÷ (0.9 × 0.6) = 7,494.

  2. Seedlings = 7,494 × 1.1 = 8,244.

  3. Cells = 8,244 ÷ 0.85 = 9,698.

  4. Trays = 9,698 ÷ 98 = 99 trays (9,702 seeds).

  5. Medium = 99 × 3 = 297 litres – about 178 L cocopeat and 119 L perlite and vermiculite.

Things to keep in mind

  • Wash and buffer cocopeat to remove salts before use, especially for sensitive crops.

  • Sterilise re-used trays to prevent damping-off disease.

  • Harden seedlings by reducing water and shade for a few days before transplanting.

Frequently asked questions

How many 98-cell trays are needed for one acre of tomato?

At 90 × 60 cm spacing, about 99 trays including 10% extra and 85% germination. Closer spacing needs more.

How much cocopeat does one pro-tray need?

A 98-cell tray takes roughly 2.5–3.5 litres of moist mix. One 5 kg block of compressed cocopeat expands to about 70–75 litres.

Which tray size should I use?

98 or 104 cells for tomato, chilli, capsicum and brinjal; 50 or 72 cells for cucurbits and other large seedlings; 128 cells for cole crops and onion.

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