What Raking Must Accomplish — and What It Must Not Do
The rake serves two purposes in the hay making system: it consolidates the dried swath into a windrow of the correct width and density for the baler, and — in damp conditions or for crops that dried unevenly — it can accelerate drying by fluffing and turning the partially dry swath. Both purposes are legitimate and valuable. The risk is when the speed, moisture condition, or rake type produces leaf shatter — the physical separation of dried leaves from stems due to mechanical impact.
Leaf shatter is the most consequential quality loss in the raking operation. In alfalfa, the leaf fraction contains approximately 65–70% of the plant’s total protein and a disproportionate share of digestible energy — it is the highest-quality part of the hay. When leaves are knocked off by the rake at low moisture, they are lost permanently: they either blow away or break into pieces too small for the baler pickup to collect. A raking pass that causes 10% leaf shatter on an alfalfa crop with 22% CP could reduce the delivered CP of the baled hay to 19–20% — a difference that crosses a market quality grade threshold on many elevator specification sheets.
Moisture Targets for Raking: The Numbers That Protect Quality
The moisture at which you rake determines both the quality loss risk and the functional purpose the raking achieves. There is no universal “correct” raking moisture — the right target depends on why you are raking and what crop you are raking.
| Crop / raking purpose | Rake at this moisture | Why this range | Leaf shatter risk |
|---|---|---|---|
| Alfalfa — premium dairy / export | 20–25% | Leaves are still pliable; rake tine contact causes flexing rather than shattering. Adequate moisture remains for safe outdoor baling after an additional 2–4 hours of drying. | Low (2–4%) |
| Alfalfa — beef / on-farm hay | 18–22% | Slightly drier target acceptable when quality standards are less strict; still avoids the brittle-leaf zone below 15%. | Low–moderate (3–7%) |
| Grass hay (orchardgrass, fescue) | 18–24% | Grass hay has more flexible leaves than alfalfa and tolerates a slightly wider moisture range for raking without significant quality loss. | Low (2–5%) |
| Raking for faster drying (tedder function) | 30–50% | At this moisture, leaves are fully pliable and will not shatter under any normal rake speed. Raking at high moisture is a drying accelerant, not a windrow-forming step. | Very low (0–2%) |
| Any crop — danger zone | <14% | At below 14% moisture, alfalfa leaves are brittle — tine contact causes immediate shattering. Quality loss from a single rake pass at this moisture can exceed 20% of leaf mass. | High–severe (10–25%) |
The practical rule: if the stems feel dry but the leaves still feel slightly cool and flexible, you are in the safe raking window. If the leaves crinkle or crumble when you rub them between your fingers, the hay is too dry to rake without significant quality loss. At that point, either bale without raking or wait for morning humidity to restore sufficient leaf pliability (typically 18–22% in the early morning).
Rake Speed: The Variable Most Operators Set Too High
Ground speed during raking is the variable most directly under the operator’s control that determines leaf shatter rate — and most operators run their rake 20–40% faster than optimal. The relationship between speed and leaf shatter is not linear: doubling the raking speed approximately quadruples the leaf impact force from the rake tines, because impact force scales with the square of relative velocity between the tine and the crop.
Optimal speed: 5–8 mph for dry hay (20–25% moisture); 8–12 mph for high-moisture turning/fluffing (30%+)
Why speed matters more here: Rotary rakes generate higher tine-to-crop impact velocities than belt rakes at the same ground speed, because the rotary motion of the rake wheel adds its own velocity to the ground speed impact. In dry conditions, faster wheel rotation at higher ground speed dramatically increases leaf shatter. Slow down in proportion to how dry the crop is.
Optimal speed: 6–10 mph at 20–25% moisture; up to 12 mph at higher moisture
Leaf shatter profile: Bar rakes have lower tine-to-crop impact velocity at the same ground speed because the tines move predominantly in the direction of travel. Somewhat more forgiving at high speeds than rotary designs, but still produce significant shatter above 10 mph in dry conditions.
Optimal speed: 5–8 mph regardless of moisture
Leaf shatter advantage: Belt rakes generate the lowest leaf shatter of any type — the conveying action moves crop rather than striking it. Ground speed is limited by the belt conveying capacity, not by leaf shatter risk. Used specifically when leaf loss minimization is the highest priority (export timothy, premium alfalfa).
A detailed comparison of rake designs and their leaf shatter characteristics by crop type is in the دليل مقارنة أنواع مشط التبن. The mowing and conditioning pass that determines the initial windrow character and moisture distribution that the rake subsequently works with is covered in the mowing and conditioning quality guide. For the PTO shaft speed requirements on rake drives, gear ratio, and rake gearbox specifications, see مواصفات مكونات علبة التروس الزراعية ومجموعة نقل الحركة PTO.
Windrow Width and the Baler Pickup Ratio
The windrow formed by the rake must match the baler’s pickup width for efficient, clean pickup. A windrow that is too wide for the pickup causes the baler tines to miss the windrow edges, leaving a stripe of hay on each pass. A windrow that is too narrow causes the pickup to sweep over empty ground between the windrow and the field surface, reducing pickup efficiency and requiring more passes to collect the same acreage.
Example: 60-inch (5 ft) baler pickup → optimal windrow = 30–39 inches wide
Example: 72-inch (6 ft) baler pickup → optimal windrow = 36–47 inches wide
A windrow width at 50–65% of pickup width allows the pickup tines to sweep 2–4 inches past each windrow edge, ensuring complete collection of loose material at the windrow margins. This marginal sweep is where the most valuable leaf fraction concentrates after leaf drop during drying — collecting it cleanly requires that the pickup runs past the apparent windrow edge by a few inches on each side.
Setting windrow width correctly requires adjusting the rake’s delivery angle or the number of swaths being merged per pass. A V-rake with adjustable wheel angle produces a narrower or wider windrow based on wheel angle setting — wider angle produces a narrower, taller windrow; shallower angle produces a wider, lower windrow. For the same rake collecting the same amount of crop, a 30-inch wide windrow will be taller and denser than a 45-inch wide windrow, with different drying characteristics after raking.
Combining Swaths: When Merging Makes Sense and When It Does Not
Combining two or more mowed swaths into a single windrow (raking wider than a single-swath windrow) is a common practice for improving baling efficiency when yield per acre is low. The decision to combine should be based on the baler’s minimum windrow density requirement, not on a desire to make fewer baling passes.
- Single-swath windrow is too light to form a full bale without requiring very slow baling speed (below 2 mph)
- Crop yield per acre is below 1.5 tons DM — single-swath windrows too thin for efficient pickup
- Field conditions allow combining without uneven moisture layering (both swaths dried to same moisture)
- The combined windrow still fits within the baler pickup width at 50–65% ratio
- The two swaths dried at different rates — combining buries wetter material inside drier material, creating moisture-stratified bales that heat unevenly in storage
- The combined windrow exceeds 65% of the baler pickup width — the pickup cannot cleanly collect the full windrow width
- The combined windrow is so dense that it causes slug loading in the baler at any reasonable ground speed
- One swath dried on rocky, elevated ground and another in a low, wet area — combining mixes two different moisture levels
Windrow Density and Baler Pickup Efficiency: Setting Up the Baler for Success
The density and consistency of the windrow is as important as its width. A windrow that varies from thin to heavy along its length — common when the rake operator drives over windrow edges and misses material — creates the slug-loading / empty-chamber alternation that reduces bale density consistency and increases the risk of shear bolt events. The ideal windrow is uniform in both cross-sectional area and material density from one end of the row to the other.
A rake that rolls rather than fluffs the swath produces a compressed, dense windrow that sits lower to the soil surface. This compressed profile can trap moisture in the windrow base and dry unevenly — the upper portion may reach baling moisture while the bottom is still 5–8 percentage points wetter. A raking technique that fluffs the swath (achieved by slightly higher rake wheel angle or a more vigorous tine arc) produces a lighter, taller windrow that dries more uniformly because air can circulate through the cross-section. For premium hay, slightly slower speed and more aggressive wheel angle to create a fluffed windrow is worth the modest reduction in raking rate.
Windrow placement consistency — keeping the windrow exactly centered on the intended row line from field entry to exit — determines whether the baler can travel in a straight, predictable path during baling. A windrow that wanders, curves, or lies at an angle to the field rows requires more baler steering corrections, reduces baling speed, and increases the likelihood that the pickup misses windrow edges on the inside of curves. Keep rake passes parallel to mower passes and to field boundaries; align at the field entry point before beginning each rake pass.
Six Raking Mistakes That Cost You at the Elevator
The most common quality-destroying raking mistake. Visible as fine dust behind the rake and a visible leaf loss trail. Schedule raking for early morning (after dew dries off, before midday heat drives moisture below 15%) or late afternoon when rising humidity increases leaf pliability.
Wind-dislodged leaf material from a raking pass is carried laterally out of the windrow before it can be collected. In a 20 mph crosswind, a finger-wheel rake can scatter 8–15% of fine leaf and chaff material outside the windrow width. Postpone raking in high-wind conditions for premium hay; for cattle hay, the quality impact is less critical.
Tines touching soil pick up mineral material that increases ash content and contaminates the bale. Check tine clearance before raking each new field, especially when transitioning between fields with different soil tilth or after rain when the soil surface is raised. Maintain 0.5–1 inch clearance between lowest tine arc and firm soil.
Combining a 22% moisture swath with a 16% moisture swath creates a mixed bale with unpredictable internal moisture distribution. The bale appears dry on the outside but contains wet internal zones that heat. Test both swaths and only combine when within 3 percentage points of each other.
A windrow wider than 65% of pickup width leaves crop at the edges that the pickup misses on every pass. These missed-edge strips are often the densest part of the windrow (the heaviest crop settled to the base) and may represent 10–15% of total crop mass. Verify windrow width against pickup width before committing to a rake angle setting.
A second raking pass to “clean up” windrows after baling recovers the material left at windrow edges but at the cost of an additional mechanical disturbance of already-dry material. Each rake pass below 15% moisture increases leaf shatter. If the first baling pass left windrow edges, lower the pickup height slightly and bale more slowly on the second pass — this collects more edge material than a second raking pass without adding leaf loss.
Hay Raking FAQs
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