Fertilisers are used to replace nutrients in the soil. The nutrients may not be in sufficient quantities needed by plants.

The three largest elements :- Carbon, Hydrogen and Oxygen are obtained by plants, air and water.

The remaining elements are split into three categories.


Nitrogen -(nitrates or ammonium) Promotes leaf growth.

Phosphorous - (phosphoric acid) Stimulates root development.

Potassium - (potash) What a plant needs lots of to swell and ripen fruit, resistance to disease, to ripen shoots, and to form and develop flowers.


Calcium, Magnesium and Sulphur, required in smaller amounts than primary nutrients.


Zinc, Manganese, Iron, Boron, Copper, Molybdenum and Chlorine.

N P K, what the label tells you.

N = Nitrogen. P = Phosphorous. K = Potassium.

The ratio's on the packaging may be 15% Nitrogen, 12% Phosphorous and 15% Potassium. Read as 15-12-15 NPK

But this does not add up. What is the other 58% ? The other 58% consists of other nutrients known as trace nutrients, but the bulk is known as a 'filler', to allow nutrients to bind to, making the application to your garden and plants easier. So what does it all mean, it means don't go buying an abundance of plant foods for specific plants, read the NPK, by understanding a plants needs you may already have something that fits the need.

A complete fertiliser contains a portion of the major plant nutrients NPK,  but not in equal quantities. 

A balanced fertiliser contains equal amounts of the three major plant nutrients, NPK

Organic Fertilizers.

An excellent source of slow release phosphorus, which is used by plants to promote strong and healthy root growth. Also contains nitrogen and calcium another essential element for plant growth. Apply from February to the end of October, every 4-6 weeks during the growing season.

Calcified Seaweed.
Trace elements to enrich soil, contains natural minerals that are essential for good
healthy plant growth and increased bacterial activity. Improves soil structure and is an ideal conditioner for all types of soils. For best results it should be used as a compliment to fertiliser dressings.

Dried Blood.
Quick acting Nitrogen fertiliser for flowers and salad crops. Apply as a top dressing and water well in after application, making certain that any fertiliser that has come into contact with the plants is washed off).

Chicken Manure Pellets.
An excellent choice as they also contain vital trace elements that are often removed from the soil by heavy feeding crops. The pellets also contain high levels of organic matter that will enrich the soil and improve its moisture holding properties, naturally. Apply February to the end of October

Fish/Blood and Bone.
Granular fertiliser. same benefits as Growmore. Contains a rich source of natural plant nutrients including nitrogen for healthy foliage, phosphorus for strong root development and also calcium. Apply from February to the end of October, every 4-6 weeks during the growing season.

Hoof & Horn.
Slow release Nitrogen fertiliser use as a base dressing, it is slow acting and is ideal for slow growing plants such as Brassicas, trees and shrubs. Also contains a small proportion of calcium that is also beneficial.

Garden Lime.
Sweetens acid soils and improves fertility. Garden lime is a calcium carbonate and helps break down heavy soils. Encourages beneficial bacteria and soil organisms.

Inorganic Fertilizers

Growmore. Granular fertiliser with equal amounts of Nitrogen, Phosphorous and Potassium, referred to as 7-7-7 NPK. Apply it as a top dressing around rows of developing seedlings, perennial vegetables, fruit trees and fruit bushes and let the weather do the rest. The rain will wash it into the soil and make the nutrients available for your plants to use. Apply from February to the end of October, every 4-6 weeks during the growing season.
Potatoes: When planting in drills, spread 3 oz per sq yard along the ridges before filling in. If planting in holes, fork 4-6 oz per sq yard into the surface 7-10 days beforehand.
Peas & Beans: 7-10 days before sowing, fork in 3 oz per sq yard. When the first pods have set, hoe in a top dressing of 1 oz per sq yard of row, spread equally on each side. Water in.
Salad Crops: 7-10 days before planting or sowing, fork in 2 oz per sq yard.
Summer & Winter Cabbages, Savoys: 7-10 days before planting, fork in 3 oz per sq yard. 6 weeks after planting, apply a top dressing of 1 oz per sq yard and lightly hoe in.
Brussels Sprouts, Cauliflowers, Broccoli: 7-10 days before planting, fork in 3 oz per sq yard. 6 weeks after planting apply a top dressing of 1 oz per sq yard and lightly hoe in.
Note: Always water on top dressings during hot, dry weather. Do not concentrate the fertiliser near the stems of plants: then the whole spread of roots will benefit.
Measure: 1 oz = approx 1 level tablespoon.

Improves the colour of flowers and the quality of fruit. Potash Power also strengthens plants, increases resistance to stress and fungus disease.
Tomato food is high in Potash and is also ideal for house plants.  Typical 7-7-17 NPK.

Sulphate of Ammonia.
 Good source of nitrogen where plants are nitrogen deficient and are showing signs of Chlorosis (leaf yellowing). Rich in Nitrogen, suitable for leafy vegetables such as cabbages, spinach, lettuce. Apply March through to the end of August, at 4-6 week intervals.

Ideal for feeding vegetables, soft fruit and fruit trees to encourage strong root growth. Recommended for use when planting trees and shrubs. Apply February to the end of October, every 4-6 weeks during the growing season.

Slow Release Fertilizers.
A modern trend is to coat the fertilizers so that they release slowly into the soil.