Wheat growth stages: Feekes and Zadoks side by side
Feekes 1–11.4 against Zadoks 10–92 in one table, how to find jointing, flag leaf, boot, heading and anthesis, and which decisions hang on each stage.
- Where:
- US winter wheat belt, Northern Plains, Ontario, Prairies
- When:
- March–July
- Updated:
- October 19, 2026
- Reading time:
- 7 min
Short answer
Feekes and Zadoks describe the same plant with different numbers. Feekes runs 1 to 11.4 and is the scale most US labels and guides use; Zadoks runs 00 to 99 as a two-digit code (principal stage, then secondary) and is the scale used in Ontario, on the Prairies and on most Canadian labels. The stages that drive decisions line up cleanly: jointing is Feekes 6 = Zadoks 31, flag leaf fully out is Feekes 9 = Zadoks 39, boot is Feekes 10 = Zadoks 45, heading complete is Feekes 10.5 = Zadoks 59, and early anthesis is Feekes 10.5.1 = Zadoks 61. A field is at a stage when half the plants have reached it. Herbicide cut-offs for growth regulators sit at jointing, nitrogen is most efficient between green-up and jointing, the flag-leaf fungicide goes on at Feekes 8–9, and the head blight fungicide at 10.5.1.
How to stage a wheat field
Stage main stems from several spots in the field, not tillers. A field is at a stage when 50% of plants have reached it. Then:
- Count leaves and tillers on the main stem for the seedling and tillering stages (Zadoks 11–15 is one to five leaves; 21–25 is one to five tillers). Wheat usually produces eight or nine leaves on the main stem.
- Slice the stem lengthwise with a knife from the crown up. At Zadoks 30 the developing head sits about a quarter inch (6 mm) above the crown and the plant has started to stand upright; that is the start of stem elongation, before any node can be felt.
- Feel for nodes. Strip the lower leaves and sheaths. When the first swollen node is above the soil surface the plant is at Feekes 6 (Zadoks 31), usually with about five leaves. At Feekes 7 (Zadoks 32) two nodes can be felt, roughly 1.5–3 in (4–8 cm) and 4–6 in (10–15 cm) above the base.
- Find the flag leaf. When a new leaf is emerging and you are not sure it is the last one, split the sheath above the highest node: if only the head is inside, that leaf is the flag leaf (Feekes 8, Zadoks 37). When its ligule (collar) is visible, you are at Feekes 9 (Zadoks 39), and lower leaves are named F-1, F-2 downward.
- Watch the head. Boot (Feekes 10, Zadoks 45) is a swollen flag-leaf sheath with the head inside. Heading runs from the first spikelet showing (10.1, Zadoks 51) to the head fully out (10.5, Zadoks 59). Anthesis begins when anthers appear on the florets in the middle of the head (10.5.1, Zadoks 61); yellow or grey anthers mean pollination has already happened, and a single head finishes pollinating in about four days.
- Press the kernel. Watery ripe (10.5.4, Zadoks 71), milk (11.1, Zadoks 75) and soft dough (11.2, Zadoks 85) follow in turn; at 11.3 (Zadoks 91) the kernel is hard but your thumbnail can still divide it; at 11.4 (Zadoks 92) the thumbnail cannot dent it and the crop is harvest ripe. Physiological maturity, when the head and the stem below it lose their green colour, falls at about Zadoks 89.
Feekes and Zadoks side by side
| Feekes | Zadoks | How to recognise it | What to scout or do | Typical label cut-offs |
|---|---|---|---|---|
| 1 | 10–15 | Emergence; one to five leaves on main stem | Stand counts; seedling pests | Leaf-stage windows on fall herbicide labels |
| 2 | 21–25 | Tillering begins | Check stand; starter N only | |
| 3 | 25 | Tillering complete; winter wheat prostrate; green-up between 3 and 4 | Fall herbicides usually beat spring ones; no spring N before green-up | |
| 4 | ≈29–30 | Erect growth begins; sheaths thicken | Ideal single spring N (K-State); start weed and insect scouting | |
| 5 | ≈30 | Sheaths strongly erect; spikelet number set; slice stem to confirm GS 30 | Ideal topdress N (Ohio); finish weed control; PGR window GS 30–32 opens | |
| 6 | 31 | First node above soil (jointing) | Last N with full yield response; T1 fungicide only if disease is in the lower canopy | No 2,4-D, dicamba or MCPA after this stage |
| 7 | 32 | Second node visible | N still responds if delayed; wheel damage starts | Ontario: most herbicides on by GS 32 |
| 8 | 37 | Flag leaf emerging, rolled | Decide on T2 fungicide; N now raises protein more than yield | Some herbicides allow early flag leaf; check label |
| 9 | 39 | Flag leaf ligule visible | T2 fungicide; scout for armyworm | |
| 10 | 45 | Boot: head swollen in flag-leaf sheath | Fungicide for late leaf diseases and glume blotch if no T2 | 2,4-D after boot traps heads and twists awns |
| 10.1–10.5 | 51–59 | Heading, first spikelet to fully emerged | Stage daily; FHB window about to open | Many strobilurin labels end at Feekes 10.5 |
| 10.5.1–10.5.3 | 61–69 | Anthesis: mid-head, then top, then base | T3 fungicide for FHB at 10.5.1, up to four to seven days after | Last timing on triazole FHB labels; PHI clock starts |
| 10.5.4 | 71 | Watery ripe; kernel length set ~10 days after flowering | Watch for bleached spikelets | Several fungicide labels end at Feekes 10.5.4 |
| 11.1 | 75 | Milk | Protect the canopy | |
| 11.2 | 85 | Soft (mealy) dough | ||
| 11.3 | 91 | Hard dough; thumbnail still divides kernel | Head armyworm; adjust yield estimate for scab | Pre-harvest herbicide labels set their own stage |
| 11.4 | 92 | Harvest ripe; thumbnail cannot dent kernel | Combine at 13–15% moisture |
Feekes 4 and 5 have no exact Zadoks equivalent; Zadoks 30 (stem elongation begun, no node yet) is the closest match to Feekes 5. Zadoks 33 (third node) and 41–43 (early boot) have no Feekes number.
The stages that carry decisions
Green-up to jointing (Feekes 3–6, Zadoks 25–31): nitrogen and herbicides. Spring N should not go on before green-up, is ideal at Feekes 4–5, and still gives a good response at Feekes 6 and 7 if weather forced a delay; at Feekes 8 and later it tends to raise protein rather than yield and can increase rust. Ontario describes GS 30 as the critical stage for N because it sets kernel number and size. Weed control should be finished by Feekes 6: growth-regulator herbicides (2,4-D, dicamba, MCPA) applied after jointing can move into the developing head and cause sterility or distortion, and 2,4-D after boot leaves trapped heads and missing florets. Sulfonylureas are labeled as safe at Feekes 6, and some products run to early flag leaf, but the benefit falls and the injury risk rises past GS 32. Plant growth regulators that shorten the lower internodes are timed to the start of stem elongation, GS 30–32 in Ontario guidance; some PGR labels run later, so check.
Flag leaf (Feekes 8–9, Zadoks 37–39): the T2 fungicide. The flag leaf supplies about three-quarters of the effective leaf area for grain fill, so this is where a foliar fungicide usually pays most for rusts and leaf blotches. Ohio's guidance puts the greatest return between Feekes 8 and 10; Ontario finds little economic benefit before GS 31–32 (T1), which makes T1 a response to visible disease rather than a routine pass.
Early anthesis (Feekes 10.5.1, Zadoks 61): the T3 fungicide. This is the Fusarium head blight timing, and it is narrow. Ontario sets Day 0 at 75% of main-stem heads fully emerged and targets Day 1 to Day 4, with Day 2 the optimum; US guidance targets yellow anthers on the middle of the head with up to four to seven days of flexibility after that. Only triazole-based products are recommended here; strobilurins are not.
Pre-harvest intervals. Labels state the harvest restriction either in days or as a growth stage, so staging is also a legal question: several strobilurin wheat fungicides must not be applied after Feekes 10.5 or 10.5.4, while triazole FHB products carry a 30-day interval from the anthesis spray. Pre-harvest herbicide labels set their own stage and kernel-moisture limits.
Why staging matters for labels and timing
Almost every wheat input has a growth-stage window on its label, written in one scale or the other. A Canadian label that says "apply from GS 30 to GS 32" and a US label that says "apply before jointing" describe the same ten days, and a grower who stages by calendar instead of by stem will miss both. Staging the main stem by the 50% rule, with a knife in hand, tells you whether the N is still worth spreading, whether the 2,4-D is still legal, and on which morning the head blight sprayer has to roll.
Sources
- Spring wheat growth and development guide (Table 1, Feekes and Zadoks scales) — University of Minnesota Extension
- Wheat growth stages and associated management (AGF-126) — Ohio State University Extension
- Wheat management for spring 2025 (C.O.R.N. Newsletter) — Ohio State University Extension
- Wheat growth and development (MF3300) — Kansas State Research and Extension
- Growth stages of wheat — SDSU Extension
- Growth stage 30, PGR timing and more — Field Crop News (OMAFRA)
- Fungicides: wheat fungicide timing (T1, T2, T3) — Field Crop News (OMAFRA)
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This guide is educational and does not replace a site-specific recommendation from your agronomist or Certified Crop Adviser. Reference to a product is not an endorsement over similar products; users assume responsibility for use in accordance with current label directions. Last updated October 19, 2026.