When feeding the garden it’s best to use natural fertilisers, such as manures, blood & bone, fish emulsion or blended organic fertilisers. No matter what kind of fertiliser we choose to use, it’s important to apply the right amount, and no more! For plants, over-fertilising is as bad as under-fertilising, and for gardeners, using more fertiliser than necessary is costly and wasteful.
How do we know how much fertiliser to use?
The product label of every commercial fertiliser list the application rate, how much to use per specified area, and also the application frequency, when and how often the product should be applied to the garden.
How Much Manure Do I Need to Feed the Garden?
Non-commercial fertilisers, such as bags of cow and sheep manure usually don’t specify application rates.
Cow or sheep manure is a fairly mild fertiliser, apply 2-4 litres per square metre (2-4L/m²) of garden bed, or 0.5-1.0 gallon per square yard (gal/yd²) in imperial measurements.
Tip: A regular household bucket holds 9 litres (2 gallons), so a bucketful of cow or sheep can be applied over an area of around 2.5-4.5 square metres (2.5-4.5m²), or approximately 2.5-4.5 square yards (2.5-4.5 yd²) and dug into the soil.
Chicken manure is a much stronger fertiliser, so it’s applied in smaller amounts, but more frequently. Apply around 150g per square metre (150g/m²), or 5 oz per square yard (5 oz/yd²) in imperial measurements, prior to planting, and then apply 100g per square metre (100g/m²), or 3.5oz per square yard (3.5 oz/yd²), every 8-10 weeks during the growth period if desired.
Keep in mind that chicken manure releases its nutrients faster than other manures, and only lasts around 6 months in the soil.
Sheep and cow manure, which are much milder manures, release their nutrients more slowly over a 12-month period.
How Often Should Manure Be Applied to The Garden?
At the very minimum, a garden should be fed with fertiliser twice a year:
- Once at the start of spring (September in the southern hemisphere, March in the northern hemisphere) for the warm season crops
- Then again at the start of autumn (March in the southern hemisphere, September in the northern hemisphere) for the cool season crops.
The garden can be fertilised more often though, as often as every 8-weeks (2 months), between spring and autumn.
In temperate climates, gardens should not be fertilised after the start of autumn. When the weather cools down, soil temperatures drop and the soil nutrient nitrogen, which is responsible for leafy green growth of plants, becomes unavailable for plant uptake.