Manure and healthy soil

Firstly; why use manure?

Manure enriches and replenishes the soil by breaking down and releasing macro and micro nutrients back into the soil, essential for healthy plant development. It helps with drainage by improving the soil structure, especially on the clay soil we have. Through healthier roots in the ground, it also retains appropriate levels of water around the plants, allowing the water to be better absorbed. Plants that are better anchored through a strong root system prevent soil run-off in the wettest of seasons. Importantly, creating a living soil helps avoid diseases and infections through the microbes in the soil. 

It is important to give back to the soil that which is taken out by the plants. Whilst fertilisers may have their place, they are normally rich in some elements but lacking in others. Manures, and therefore, “home made” compost has the basis of all the nutrients, in the appropriate concentrations. If you are growing plants which need particularly higher concentrations of certain minerals, then this may be supplemented and directed to that plant only, rather than applying it generically, and potentially spoiling the development of other nearby plants.

If the soil is replenished properly, and therefore, a living soil is created, then this takes out the guess-work of what might be needed and when, because the plants themselves draw what they need from the soil, using the elements that are essential to them individually at that time in their particular growth cycle. 

Every plant we grow uses different nutrients from the soil at differing rates according to their point of growth: seeds use the least nutrients from soil as they are naturally packed with their own powerhouses of nutrients. Roots develop with the help of potassium and phosphorous, encouraging strength and disease resilience. Leafing plants particularly use nitrogen, as well as the other macronutrients phosphorous and potassium. Those that develop into flowering plants use more phosphorous and potassium to cope with growth, maintaining health, and then producing the flower. Fruiting plants, in this allotment scale, use the essential elements calcium and potassium more towards the end of their season to produce the fruit, and more of the micronutrients such as copper and zinc. These aren’t the only minerals needed, this is to show how they are needed at different points in the plant cycle.

Enriching the soil creates a living mass of microbial activity, which not only encourages growth and healthy plants, it also contributes to controlling or avoiding diseases. Healthy plants are more resilient to pests and disease.

Secondly; which manure and when?

Manure – all types can be used, except that from meat eating animals is acceptable. Rabbit manure can be used immediately because it is considered “cold” but cow, horse, and chicken manures create heat when they breakdown. To this end, manure is usually matured for 3 to 6 months prior to use to avoid manure burn.

What causes manure burn, apart from the obvious heat produced? 

• Excessive nutrients: Manure, especially fresh manure, contains high amounts of soluble nitrogen and other nutrients. 

• Salt buildup: Fertilizers, including manure, contain salts that can draw moisture out of plant tissues, leading to dehydration and damage.  

• Over-application: Applying too much manure or fertilizer can lead to nutrient toxicity, causing the plant to struggle to absorb water and nutrients.  

• Application timing: Applying manure or fertilizer to wet or damp plants can exacerbate the issue, as the salts can quickly draw moisture from the plant.

Maturing Manure

There are a couple of ways to do this. Either by putting the manure onto the compost heap (which also helps to speed up the composting of other garden matter) for up to 6 months depending on your preferred schedule, or putting manure on the bottom layer of the lasagna bed. 

If using the lasagna method, the manure will gradually break down and release the nutrients in the normal way. This is probably best done when preparing beds for use three months ahead, unless you are raising the bed significantly. In March, for example, putting manure at the bottom of the bed means the soil should be ready for the corn and squash to be planted in June, both of which are heavy feeders. Likewise, manuring the bottom of the bed in June means that the soil should be ready for winter growing vegetables sown in Autumn, such as the winter and spring cabbages. Equally, given cruciferous vegetables require different levels of heavy feeding to that of corn and cucurbits, growing these for winter and spring in the same bed means using the manure to its fullest potential, as well as saving space, crop rotation, diversity and continuing to use soil, all of which improve the structure and avoid soil run off. 

An example of a lasagna bed in this instance:

• Manure 2 to four inches

• soil, two to six inches,

• kitchen waste, not cooked, and/ or barley straw/ garden chippings.

• soil, two to six inches,

• compost, 2 inches.

• Grow.

• Chop and drop. (take what you have grown to eat, but leave the excess – chopped – in the bed to decay)

Following season, add more compost, or if the bed is resting for the season, matured manure.

Grow, repeat. Eventually, you will have a no dig-garden, living soil and better, healthier plants.

Please note, root vegetables typically do not like recently manured beds, so remember to delay these vegetable plantings in a recently manured bed by at least two seasons before planting – using the above example: manure in March, grow corn and squash, then spring  cabbages, followed by carrots next Spring, this prevents the roots forking due to too much nitrogen. Rotating the vegetables like this also helps with plant biodiversity, which in itself helps to maintain healthy soil, reduce soil run off during wintering months, and confuse visiting pests/deter soil borne pests and reduce diseases.

Using the heat from manure breaking down

Earlier, I reminded you that horse, cow and chicken manures create heat when they breakdown. If you prefer to harness this heat whilst waiting for the manure to compost down, there is a wonderful article on the web explaining how to do this 

https://www.edinburghgardenschool.com/2017/05/hot-beds

Lydia Frew has created one for this year, and is currently using it now. If you would like to see this and ask questions, Lydia is more than happy to discuss to advantages, drawbacks and experiences using varying methods for creating hot beds.