Timing is important for dragging horse pastures. It needs to be done at a time of year that the manure can be spread over the pasture without danger of spreading worm eggs around.
“Typically people harrow pastures in the spring,” said Bob Coleman, PhD, State Equine Extension Specialist at the University of Kentucky.
Coleman said that dragging works well for horse pastures that were used a lot in the fall and won’t be used again for a while. You can drag those and break up the manure piles to help the manure break down faster than if you just leave it in piles. Dragging gets the large piles off the grass so they don’t kill the grass underneath. If you drag pastures in the spring, it is best if you don’t use those pastures again for a while to allow the parasite larvae to die.
“If you drag pastures in the summer, do it when the horses are somewhere else and the weather is hot and dry so the parasites will dry out and die before the horses go back into that pasture," advised Coleman. "Have a plan so that when you drag it, there will be some time elapse before grazing—at least a couple weeks."
Parasites are affected by weather. Dragging a pasture when it’s warm and moist will just contaminate the whole pasture with worm eggs that can readily hatch and crawl onto grass plants to be eaten. “Not dragging a pasture is just as bad, however," said Coleman. "There will be places where large fecal piles will smother out the grass and kill it, and then the only thing that will come back is weeds.
“When the manure starts to break down and decompose, however, spreading it around is a good way to put some nutrients back into the soil," said Coleman. "Even if you get some hot, dry weather, it’s amazing how intact those piles are. But if you break them up into smaller piles and pieces, those fecal piles will dry out and break down quickly. The action of weather, temperature and humidity will all help break it down.”
If you drag the pasture then it rains a lot, let it dry out again before you put the horses back in.
“Pasture management requires flexibility rather than doing things by the calendar; the grass health should be your priority," said Coleman. " If you have to wait another day before you put the horses in, or if you have to move them out quicker than you’d planned, that is part of the flexibility required.”