Summer Fertilizer Increases Alfalfa Winterhardiness

Corey Headshot PNG

Core Catt, Forage Product Manager

With everything from groceries to gas on the rise, we understand the need to question whether expenses are necessary or justifiable. Below is information to support why fertilizing alfalfa in summer and applying fungicide to silage hybrids warrants your attention.

Fertilizing alfalfa in the summer helps fill the cellular gas tank of the plant’s crown, which helps increase its yield potential for the current growing season, as well as increases its potential for winterhardiness. All alfalfa benefits from in-season fertility, regardless of cutting schedule or strategy.

Summer seeding is fast approaching. July 20 through August 1 are key seeding dates for Latham Hi-Tech Seeds’ northern territory, which includes North Dakota, as well as northern Minnesota and northern Wisconsin. August 1-15 is the range of recommended alfalfa seeding dates for southern Minnesota and southern Wisconsin while most alfalfa growers in Iowa typically seed in mid-August. Look at this graph.

Corey Graph

Sourced from University of Wisconsin – Extension

Due to our late spring, many Midwest alfalfa growers have moved seeding alfalfa to this fall. The success of fall seeding depends on moisture. It’s important that alfalfa germinates quickly, develops a crown, and builds enough crown carbohydrates to overwinter.

Latham® AlfaShieldTM is a great seed treatment to help facilitate quick emergence. Think of AlfaShield as wrapping your alfalfa seed in a sponge. It helps protect the fragile germ of the seed. It also helps draw moisture to the seed, which is particularly important when seeding into moisture-stressed soils. Summers-seeded alfalfa is up against the time clock; approximately four to six weeks of significant growth needed to develop the crown before frost. The 2022 and 2023 Latham product guides include a dry matter (DM) ton advantage of AlfaShield compared to the old industry standard. AlfaShield has a bigger advantage in moisture-stressed soils.

Summer Considerations for Corn Silage

When I walk fields and test plots in the fall, I note a hybrid’s stay-green ability. I believe this observation relates to plant health. Healthy plants tend to have a lower probability of developing infection, which can create the environment for molds and mycotoxins to grow.  Fungicide application promotes plant health and can boost yield and corn silage quality. Healthy, dark green, disease-free leaves are like solar panels capturing more sunlight for more photosynthesis. Healthy leaves also build more yield, as well as reduce chances for mold and mycotoxins to develop.

There are a variety of fungicides to select from, all of which inspire improved plant health. I have the most experience with BASF fungicide corn silage research relating to improved corn silage tonnage and forage quality. Several of the studies have resulted in two to three more tons of corn silage per acre plus the potential of reduced molds and mycotoxins is encouraging. With current commodity prices, that’s around an extra $140 to $210/acre in corn silage tonnage!

Investing fungicide is worth consideration for livestock producers, who raise their own forages. Molds and mycotoxins can be more challenging to quantify. When fed to livestock, however, they can severely impair animal performance. In severe instances, it can lead to mortality.

Feel free to contact your local Latham rep with any questions about summer fertilizing or fungicide application. You’re also welcome to email me at I’m always happy to visit with Midwest farmers who are interested in raising better meat, milk and eggs!