Effective weed control starts with having good healthy pastures and hayfields, which was the first sentence spoken by Penn State Extension Educator Andrew Frankenfield. His presentation was part of a hay production seminar in Lancaster, PA recently. “Harvesting at [the] proper time is another concern,” he said. “Fourth of July first cutting, isn’t quite the best time…because those weeds have gotten bigger. But if you’re cutting aggressively, you’ll keep those weeds in more of a vegetative stage, not in a reproductive stage.” Frankenfield says he gets calls all year from people who tell him “I got this in my hay,” and they haul 12 Ziploc bags to his office. “And I tell them ‘well, yes, that’s poisonous. That’s milkweed (technically poisonous). That’s hemp dolvane. That’s smooth bed straw.’ I tell them that it’s between you and the person who bought your hay that determines where you go from here.” He maintains he doesn’t like throwing anyone under the bus when they make poor quality hay. The unofficial credo is to know your customer and keep the customer happy. Be able to provide a good quality product to them so they will want to buy from you next year. People, naturally, are concerned about poisonous plants. You want to make sure they are getting a quality product, and you’re not liable for sickness, illness or death. It’s an unpleasant process to go through.
“How do we control weeds? Grazing [and] mowing. These are typically the way we go about it,” Frankenfield said. Also, keeping a good quality grass stand in place. If you kill a weed, something else will grow where the weed was, and most likely it will not be a desirable plant like you have in the rest of the field. A PowerPoint slide showed a Kentucky field which was grazed and not mowed afterward. The other side was grazed and mowed for thistle control. It looked better. “Just the ability of mowing your hay field is a good practice.” Frankenfield gets calls from farmers who say they want to plant a hay field. “And it’s…September thirtieth,” he bemoaned. “Or maybe it’s October thirtieth. ‘Can I still plant it?’ they want to know. They can do whatever they want,” he said, “but ideally you should get those fields in by the first of September to give them a couple months of growing time before winter sets in. Don’t try to plant them on Thanksgiving Day!” He visited a farm where the farmer planted in the middle of September. “September and October are dry, as you know, and they did not take off real well. Then geese and deer beat it up. Try and be ready. Get your fertility in place and get your lime done ahead of time.” In other words, have a plan.
Often people want to try to inter-seed in their fields, a technique which has mixed results. Frankenfield reminds us there is already a crop growing and competing for space. “Seeding on the previous year’s row as opposed to the previous year’s inter-row has been shown to enhance soil water content,” according to the Grains Research & Development Corporation in Australia. “The remnant root systems of the previous crop are thought to provide pathways for water into the soil. Dead plant crowns and root systems from a previous crop, if left undisturbed, seems to improve the wetting of repellent soil by rainfall after harvest and into the next growing season. It appears that rain wets-up a thin layer of topsoil and flows into channels remaining from the previous crop roots.”
“We have seen some effective inter-seeding of grass into an alfalfa stand,” Frankenfield said, but “often inter-seeding grass into grass is questionable.” There are no guarantees. Weed problems out there spring from many clans. There are winter annuals, chickweed, dead-nettle, biennials, and perennials like horse-nettle, milkweed, and dogbane. If none of those ring a bell and you don’t know what they look like, it would be wise to look them up and be able to identify them. Knowing how and when to spray them is another plus. What’s the secret to keeping established stands, or stands which are being established, clean? “When we start out,” Frankenfield said, “the most important time frame is the first couple months after you seed, once you get your grass or your alfalfa up and you’re ahead of the game. Get rid of those weeds that are out there, especially those perennials.” Manure can be a weed source, but there’s a risk depending on what you’re using. “Be aware of what’s around you. Is there a tobacco farmer nearby? Vegetables? Grapes? You have to be mindful of these products and their drift potential.”
Be mindful also not only of grazing restrictions but also haying restrictions. How long from your application until you can make hay again? Obviously, you don’t want to spray right after you cut that field if you’re looking to kill a broadleaf weed.