For improving the soil in the vegetable garden, manure is highly favored by gardeners. This organic material from animal and plant sources benefits both the soil structure and the growth of plants.
What is manure, actually?
Manure’s key ingredient is solid animal excrements and farm animal urine. It’s often mixed in with bedding material (straw, wood shavings…). It’s very rich in organic materials, around 30%. Since it combines both animal and plant sources, it contains varying amounts of nitrogen, phosphorus, and potassium. However, it’s a material that is very much alive, so it changes over time. Therefore, you can find it in various forms:
- Fresh, it has just been produced by the animals. Use with caution as it might contain germs, residues from animal treatments, and weed remains.
- Mature or aged, it has been left in a pile exposed to the open air for several months. This manure has had time to break down naturally. Part of the process is reaching a temperature of at least 122 °F (50 °C), which helps kill harmful germs and bacteria.
- Composted, is when the manure is mixed together with compost to decompose. You can make it at home or buy it in a bag.
- In dried pellets, it’s very handy for gardeners who don’t have access to fresh or mature manure.
What is the purpose of manure?
Composed of fecal matter and fibrous material (straw), manure offers several benefits for both soil and plants.
- It amends soil, meaning it improves soil structure and texture. Thus, depending on the type and quality of manure, clay soil becomes lighter and light soil becomes more dense. And logically, soil quality increases: higher air porosity, and much better water and fertilizer retention. In this regard, manure plays the same role as compost.
- Manure boosts soil’s biological activity since it’s a source of food for microfauna. All microorganisms and earthworms transform this material into humus.
- It has a fertilizing role due to its high content of nitrogen, potassium and phosphorus, and also minerals. It therefore promotes plant growth. Manure can thus be considered a fertilizer, but it is less potent than ground horn or dried blood or seaweed.
Different types of manure
Depending on the animals that produce it, you would get different types of manure and therefore different quality (or grades):
- Cattle manure is composed of dung and straw, rich in organic matter (nitrogen and potassium) due to the large amount of grass cows consume. Moreover, it’s a type of manure that greatly contributes to humus in the soil. It’s considered “cold” manure because it decomposes quite slowly.
- Horse manure or donkey manure usually mainly consists of droppings, without as much straw, making it a so-called “hot” manure. Rich in nitrogen and potassium, it’s relatively light. It’s the perfect manure for use in hot beds.
→ To learn more: Use horse manure in the garden and vegetable patch
- Sheep manure (sheep and goats) is the manure that’s most rich in potash. Like horse manure, it’s a dry and hot manure capable of warming soil up.
- Poultry manure consists of chicken droppings and/or other poultry and its litter. It’s the manure that’s richest in nitrogen and should never be used as is. Chicken droppings must absolutely be dried and composted.
- Rabbit manure is a hot manure.
- Pig manure and slurry are mainly used for spreading on agricultural land.
As a general rule, cold manures are more suited to limestone and siliceous soils, and hot manures to clay soils, which they lighten in structure.
→ To learn more: Identify the type of your garden soil
How to use manure in the vegetable patch?
Fresh manure you would simply spread on bare soil throughout the vegetable garden in fall or in winter. It forms a warm cover that acts like thick mulch. As a side benefit, this thick layer significantly disrupts weed growth. And the manure will slowly breakdown until spring to amend and enrich the soil underneath. In spring, as you dig or simply run a broadfork along the plot, the decomposed manure mixes into lower layers below. Count about 2 to 10 pounds per square yard (1 to 5 kg per m²), depending on the type of manure.
Mature or composted manure is spread in spring, just before planting or sowing your first vegetable plants. You just have to lightly incorporate it into the soil with a hoe or claw. You can also toss a shovelful of it at the foot of more nutrient-hungry vegetable plants like tomato or zucchini. Count about 2 pounds per square yard (1 kg per m2).
In any case, absolutely remember never to spread fresh manure directly at the foot of plants as it would literally burn them.
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