For added fall fescue growth, hold off nitrogen until August


Tall fescue, Missouri’s most used pasture grass, provides fall and winter grazing with proper management.  With growing concern about the lack of stored forage, grazing offers potential feed this year.


Fescue grows in two distinct seasons, spring and fall. Fall growth isn’t as robust as in spring. With good management, fescue gives grazing well into winter. An advantage of fall tall fescue growth is that it can stay standing and edible past frosts and even winter storms.  Grazing, especially management-intensive grazing, reduces the need for baling hay for winter feed. That cuts costs and labor.


MU forage specialist Craig Roberts says July is when thinking about managing fescue should begin. August brings a time for action with much of needed growth coming in September. With fall fescue growth, thinking before acting improves benefits.


Fall grazing depends on Missouri weather. Lack of rain or early freeze changes growth dynamics.  Roberts says unusual early rains this summer may have producers jumping the gun.  A key part of increased production depends on a boost application of nitrogen fertilizer. That helps fall growth.    “Don’t add nitrogen now,” Roberts says. “Added fertility will just give you high yielding foxtail or other annual warm-season weeds.”  The other yield booster is to graze down existing pasture before fall growth starts. That includes lowering annual grasses and legumes in the fescue. “Clear the deck for the fall growth,” Roberts says.


This isn’t time to assume that if a little bit of fertilizer is good, then a lot must be better. Adding nitrogen to toxic tall fescue takes caution. Nitrogen does boost grass growth but also increases fescue toxicosis.  Fescue toxins bring a host of bad side effects. In extreme cases, the ergovaline causes fescue foot, which kills cows. More subtle losses are in lower gains, less milk, heat stress and other ills.  Toxins are low in summer months but can come in hot weather. Then cattle quit grazing and head to ponds or creeks to cool off. Early application of nitrogen in July increases toxins, detracting from fescue’s advantages.


The cautions from forage specialists come in timing and limiting nitrogen spreading. “With toxicity, 50 pounds of N hits the maximum limit,” Roberts says.  Producers thinking ahead and killing their toxic K-31 fescue to seed non-toxic novel-endophyte fescue see great potential.  The new fescues take more fertility. “Go for 80 to 100 pounds of nitrogen per acre on novel endophyte,” Roberts adds. “There’s no threat of fescue foot and all of that.”

Fertilizer timing varies across the state. “In mid-Missouri the target application date is Aug. 15. In northern Missouri, earlier at Aug. 10 works. In the Ozarks, closer to Arkansas, delay until late August.  Even if it looks like there’ll never be another rain, Roberts urges applying nitrogen on suggested dates.


Usually, farmers count on fall rains starting September 1st.  Sometimes Gulf Coast hurricanes change that date. Tropical storms bring extra rain to mid-America. That grows more grass.  For maximum benefit from fall growth, rotational grazing extends stand usage. Methods used for management-intensive grazing (MiG) are taught at MU Grazing Schools.


Regional MU agronomists teach grazing management and can be contacted through local county MU Extension offices.