It's time to get down to the dirty truth of growing stuff. That's right, we're talking about the original fertilizer here: animal manure. The stuff bodies can't use is good for plants.
Generally, manure brings nitrogen to the soil, along with beneficial organisms — that is, when done right. When it's, ahem, mishandled, you can get weeds and — worse — E. coli. Do the benefits outweigh the risks? Gardeners answer with a big Y-E-S.
According to Pam Rouhier, lawn and garden salesperson at the Medford Grange Co-op, manure delivers an organic shot of nitrogen to the garden, so it should be thought of as a fertilizer. Commercial products are baked to be free of weeds and dangerous organisms, and their fertilizing power should be listed on the bag.
Chicken manure delivers the biggest punch: the N-P-K is 1.5-2-1.5. Farmyard manure may be mixed with so much carbonaceous material, like straw, that it may not be considered a fertilizer.
Buy quality manure from a brand you trust. "There could be a higher salt content in some bagged manure," says Rouhier.
Another caution about cow manure is that some cows are routinely fed antibiotics, which are then passed into the manure. Basically, this would kill soil organisms and work to your disadvantage. Chickens are raised under more controlled conditions than cattle, so may be a safer bet.
Locally available manures are likely to have a higher nitrogen component. When you are picking it up from a farm, make sure it has been composted. Then to get the best results, test the material.
"Manure's not balanced with basic plant nutrients," says Rouhier. "Test your compost so you know what you are putting in."
Soil-test kits are inexpensive, provide the materials for multiple tests and are accurate enough to guide your application. Rouhier advises taking samples from a number of spots in the compost to get an accurate read.
Pig manure is almost the next best thing to chicken, she says, adding that only rabbit manure is better. As a small farmer, she regularly used manure from her pigs in her vegetable garden but never without composting the material for a year. The same requirement is true for all animal manures. Composting kills E. coli.
Other types of manure that serve gardeners well are sheep, horse, goat, turkey and llama manure.
If you have fresh manure, pile it up so it can retain heat and begin to cook, advises Rouhier.
"You can see it steam in winter," says Rouhier. "The interior cooks, so turn the pile periodically, so it all gets heated."
Interested in the exotic? Bat guano has the most nitrogen by far: 10-6-2. Expect to pay for that. Fish meal, once a plentiful source of fertilizer in the Pacific Northwest, is now more expensive and less available, due to changes in fishing techniques and decreased waste.
Worm compost, available at the Rogue Valley Growers & Crafters Market, can be put directly into the soil. Generally called worm castings, it has very little odor and great tilth.
The most exotic manure in this area can be found at Wildlife Safari in Winston. Dubbed "ZooDoo," it is gathered from the hippo, giraffe and elephant barns, other herbivore feed stations and field cleanings. It's carefully composted on site and available by the truckload, says John "Gobie" Gobershock, maintenance supervisor.
They heat it to destroy seeds over a nine- to 12-month period.
"We sell it all the time," says Charlotte Blair, a receptionist with Wildlife Safari. Blair uses the material in her own garden.
"It's kind of hot, so you have to mix it in, or it will burn your vegetables."
It's a hit with home gardeners living near the animal park, but it takes at least two hours to get to Wildlife Safari from the Rogue Valley, so you may want to tour the park as part of your trip. A pickup load of ZooDoo goes for $20. Prices decrease if you buy larger quantities, and they do sell it by the dump-truck load. Call ahead for reservations, 541-679-6761, ext. 200.
The best time to add manures is before planting. Let the soil rest for a few days before putting in starts. Incorporate into the top 2 to 6 inches of soil, depending on the amount you use.
Then remember to wash your hands.