Most liquid manure fertiliser recipes call for using composted material. This is because fresh manures are too strong, or "hot" to use on plants without seriously burning or killing them. Composted manure has aged, decomposed and cooled off. But not everyone has the time, space or desire to deal with composting poop themselves. You can make your own liquid horse manure fertiliser with fresh droppings in the autumn, well ahead of planting time. Simply allow your garden to do the composting for you. This recipe is sufficient for feeding about 9 square metres (100 square feet) of garden area.
Situate a 248 litre (55 gallon) drum where it won't be in your way. Fill it about half full of water. You'll need to do this several weeks before fall preparation of your spring gardening site.
Fill a 23 litre (5 gallon) bucket with horse manure. This is a convenient way to measure up about 20.5 to 23 kg (45 to 50 lb) of poop.
Divide the manure into two large old pillowcases or burlap bags. Twist the open ends and secure each with a knot.
Put the bagged manure in the 248 litre (55 gallon) drum. Fill it the rest of the way with water to about 15 cm (6 inches) from the top. Allow it to steep for 3 to 4 weeks.
Remove the bags of manure and squeeze the excess fluid from them into the drum.
Cultivate your spring gardening site as you usually do. Incorporate the liquid horse manure fertiliser into the top 15 to 20 cm (6 to 8 inches) of soil. This will give the hot manure plenty of time to age and decompose into the soil, making it safe for spring planting.
Always wear gloves when you're handling manure products. While the presence of pathogens isn't likely, there's no point in taking chances. Wash up well afterward.