How Cutting Height Affects Regrowth and Long-Term Hay field Productivity
⭐ Introduction
Cutting height is one of the most powerful—and misunderstood—factors in hayfield performance. Many producers cut as low as possible to “get the most tonnage,” but mowing too short can reduce regrowth speed, shorten stand life, weaken root systems, and increase weed pressure.
This guide explains how cutting height affects regrowth, long-term field productivity, hay quality, and the health of your forage crop.
🌱 Why Cutting Height Matters
The height at which you cut determines:
- How fast the plant regrows
- How well it survives stress
- How much root energy remains
- How many years the stand will last
- How many weeds will invade
- Feed quality vs tonnage tradeoff
Cut too low → fast short-term gain, long-term loss.
Cut correctly → faster regrowth and longer stand life.
🌾 1. Cutting Height and Carbohydrate Reserves
Plants store energy in their lower stems and crowns.
If you cut too short, you remove the plant’s “battery,” delaying regrowth.
Cutting too low causes:
- Slow regrowth
- Reduced yield on the next cutting
- Weaker root mass
- Increased susceptibility to drought
- Lower winter survival
Cutting higher results in:
- Faster green-up
- Stronger plant vigor
- Improved long-term productivity
🍃 2. Ideal Cutting Heights by Crop Type
Alfalfa
Recommended cutting height: 2.5–3 inches
- Cutting lower increases soil contamination
- High risk of crown damage
- Reduces stand longevity
- Greatly slows regrowth
Alfalfa can tolerate lower cutting than grasses, but cutting too low repeatedly reduces stand life by 1–2 years.
Grass Hay (orchard grass, fescue, timothy)
Recommended cutting height: 3–4 inches
Grasses store energy in their lower leaf bases, which must remain intact.
Cutting below 3 inches leads to:
- Very slow regrowth
- Thin stands
- Weed invasion
- Poor yields on second and third cuts
Grass hay is the most sensitive to being cut too short.
Mixed Stands (alfalfa/grass)
Recommended cutting height: 3 inches
Cutting too short favors alfalfa and harms grasses.
Cutting too tall favors grasses but reduces alfalfa tonnage.
3 inches is the perfect compromise.
🚜 3. Cutting Height and Weed Control
Cutting too low weakens forage plants and creates a perfect opening for weeds like:
- Fox tail
- Pig weed
- Thistles
- Ragweed
Leaving a 2.5–4 inch stubble shades the soil and reduces weed germination.
🔥 4. Cutting Height and Heat/Drought Survival
Taller stubble protects:
- Soil moisture
- Plant crowns
- Root systems
- Regrowth points
Low cutting leaves plants exposed to heat stress and summer droughts, especially during the second and third cuttings.
🌿 5. Soil Contamination and Hay Quality
Cutting too short increases the amount of:
- Dirt
- Dust
- Sand
- Soil microbes
This leads to:
- Dusty hay
- Mold risks
- Lower TDN and RFV
- Reduced palatability
- Buyer complaints
A slightly higher cutting height produces cleaner, more marketable hay.
🧮 6. Cutting Height and Yield Tradeoff
Yes—cutting higher may reduce the first cutting yield by 5–10%.
But it increases:
- Second cutting yield
- Third cutting yield
- Stand longevity
- Total season tonnage by 10–20%
Cutting too short is a classic case of “short-term gain, long-term loss.”
🧰 7. How to Maintain Correct Cutting Height
✔ Check mower deck frequently
Uneven ground can cause scalping.
✔ Use shoes/skids on discbines
Set shoes to maintain desired height.
✔ Slow down on rough ground
Fast mowing causes cutterbars to dip.
✔ Recheck height after blade wear
Worn knives cut lower than new ones.
⭐ Conclusion
Cutting height has a huge impact on hay quality, regrowth, and long-term field productivity. By cutting alfalfa at 2.5–3 inches and grasses at 3–4 inches, you protect your stand, improve regrowth, and increase total seasonal yield. A slightly higher stubble today means a stronger, more productive hay field tomorrow.
