Technologies K–10 · Years 5–6

Sowing depth: when do wheat seedlings emerge

Living World (NSW Science and Technology K–6, 2017, agriculture); Design and Technologies: Knowledge and understanding, Technologies context: Food and fibre production (ACARA v9)

PracticalMedium risk

School laboratory, not for home

In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.

The idea

In a managed crop, sowing depth is a decision: a seed sown deeper must grow further on its stored food before reaching light, so it emerges later, which is why farmers set air seeders to a chosen depth.

Safety card

Medium riskA teacher supervises

Setting: In a school laboratory, with a teacher supervising, under the school's risk assessment. Not for home.

Hazards

Seed-raising mix, like other potting mix, can carry Legionella longbeachae, bacteria that cause Legionnaires' disease when dust from the mix is breathed in; opening and pouring dry mix is the step that raises that dust

Controls

Before the lesson an adult, wearing gloves and a P2 (N95) respirator, opens the bag outdoors, wets the mix down and fills the three cups, with no learners present
Learners handle only the damp mix, wearing gloves, and no learner opens, pours or stirs dry mix
The bag is closed and stored away from the learning space, and no dry mix is tipped out during the lesson
Hands washed after handling the mix and before eating or drinking

Note

No heat. NSW Health advises wetting potting mix down to reduce the dust, wearing gloves and a protective mask (N95/P2 respirator) when using it, and washing hands afterwards (NSW Health, Legionnaires' disease page, read 2026-09-23). That respirator is worn by the adult who opens and wets the mix, because a respirator protects only while it seals to the wearer's face: learners are not given one and do not handle dry mix. Risk is medium, not low, because the mix can carry Legionella longbeachae. Record the activity on Primary School RiskAssess (riskassess.com.au) (potting mix).

What you need

30 wheat seeds (untreated, from a garden supplier)
3 clear plastic cups, each at least 12 cm deep, with drainage holes, filled with seed-raising mix
Ruler, spray bottle of water, labels
Tally chart for days after sowing

How to do it

Label the cups 1 cm, 3 cm and 6 cm. An adult wetted the seed-raising mix down and filled the cups before the lesson, so learners meet only damp mix.
Sow 10 seeds in each cup at its labelled depth, measuring with the ruler against the clear side, and cover.
Keep all cups in the same place and water them the same amount each day.
Each school day, count the seedlings that have broken the surface in each cup and record the day.
After 14 days, record the total that emerged from each depth.
Compare with the 2 to 5 cm depth that air seeders use and explain the farmer's choice.

What you should see

Seedlings from 1 cm and 3 cm emerge first; seedlings from 6 cm emerge later and fewer may emerge. The shoot grows on the seed's stored food until it reaches light, so a deeper seed has further to go. The Grains Research and Development Corporation unit on Primezone describes air seeders placing wheat seed about 2 to 5 cm deep; that range trades reaching soil moisture against the distance the shoot must grow. The learner knows it worked when the first emergence day is latest in the 6 cm cup.

What changes

What you change: sowing depth (1, 3, 6 cm)
What you measure: days to emergence and number emerged by day 14
What you keep the same: 10 seeds per cup
the same seed-raising mix
the same watering
the same position

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

Deeper seeds grow stronger because they are safer (they may run out of stored food before reaching light).
Seeds need light to germinate (wheat germinates in the dark soil; the seedling needs light once it emerges).
All seeds sown will come up (some do not emerge, which is why farmers test and adjust sowing rates).

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

Science and Technology K–6 Syllabus (2017), NESA. The syllabus taught in 2026; the 2024 syllabus replaces it from 2027. Code read from the official syllabus document (DOCX) on 2026-09-22.ST3-5LW-T ST3-2DP-T
Science and Technology K–6 Syllabus (2024), NESA. Implementation from 2027, so this code describes the future syllabus. Code read from the Stage 3 content page on 2026-09-22. Skill outcome only: neither Stage 3 focus area has a food or fibre content point; the entry is a fair test with the variables it lists.ST3-PQU-01
Australian Curriculum v9AC9TDE6K03

Sources

The pages the author read to write this activity.

All Concept Studio activities