Fertilising soil, naturally

This week Latis sit down with Wendy ‘Woo’ Sweet from her home in County Mayo, to discuss the chemistry of healthy soil and how to achieve this using naturally available products.

Understanding fertilisers and soil improvement can be confusing at first glance, and you wouldn’t be mistaken in thinking you need a degree in chemistry to achieve it! But it’s actually very simple and a key factor in successfully growing your own fruit and veggies.

To thrive, plants need food, water, daylight, and a comfortable place to grow.

Natural fertilisers have the advantage of providing both the organic structure for the soil, and the balance of most required nutrients and minerals in a safe and controlled manner. Which is an essential key in gardening sustainability.

A wheelbarrow of compost, manure, or seaweed is great and always welcomed for nutrient starved soil. Whereas the use of non-organic commercial fertilisers could burn or damage plants and roots, upsetting the delicate balance of soil. 

Table: Nutrient content of natural fertilisers

Natural Fertilisers

These are my tried and tested favourites.


Foraged washed up seaweed is a great way to improve soil and feed beds over winter. Once collected leave stacked so excess salt dries out, this takes approximately a month. Then add shredded and cut to beds in late autumn. This needs to be at least 3inches thick and left on as mulch throughout winter. Dig in spring.



Liquid seaweed concentrate

I use this weekly and have done for many years. Once a week, early morning, before sun gets too hot to avoid scorching any leaves. This can be used as foliage spray, spraying all edible fruit trees, bushes and vegetable crops. This can also be watered down and is ideal for seedlings.




Farmyard manure must be rotted down for at least a year, in a heap or compost bin before applying to beds. 

Manure mixes well with garden waste and composable kitchen waste too. Garden worms also thrive, when added this will further improve soil structure.



Chicken Manure Pellets

I often use these too. Approximately 25 grams per square meter, sprinkled over the soil around base of crops. 



Green Manures

These are sown plants grown to dig into soil to add nitrogen and organic matter to soil, these are great for fallow ground or beds not being used so not left bare.

Red clover, Borage Comfrey, Ryegrass Lupin and pea to name a few.

There are so many more choices, for example mushroom compost, fish blood and bone etc. All dependant on soil type, conditions and personal preference.

Happy gardening!