Guide to Fertilisers

Plants need nutrients to grow and stay healthy. The three most important are nitrogen (N), phosphorus (P) and potassium (K), which is why most feeds usually show an N:P:K ratio to indicate the levels of these three nutrients.
Nitrogen, phosphorus and potassium all have a different function. Nitrogen is needed for healthy leaves, phosphorus is important for healthy root growth and to ripen and harden stems and potassium (also known as potash) is important for flowering and fruiting.
Along with the three main nutrients, there are a number of minor nutrients (also known as trace elements) that are needed in smaller quantities, such as copper, boron and iron. A balanced feed will contain equal amounts of N:P:K along with smaller amounts of the other minor nutrients, whereas a tomato feed, for example, will contain more potassium because it’s used to encourage fruits.

GENERAL PURPOSE FERTILISERS
THESE are the fertilisers you need if you want all round healthy growth – healthy green foliage, strong roots, heavy crops and beautiful flowers. They either come as soluble feeds for mixing with water or in granular forms for scattering directly onto the soil.

Growmore  
N:P:K 7-7-7  
Ideal for the whole garden, usually comes in a granular form. Vitax also do a liquid version.

Miracle-Gro All-purpose Plant Food (Scotts)  
N:P:K 24-8-16 plus trace elements     
Ideal for the whole garden, available as a liquid feed, a concentrate or a slow-release granular version.

Phostrogen (Bayer Garden)   
N:P:K 14-10-27 plus trace elements   
An all-purpose soluble feed plus trace elements ideal for the whole garden. Huge range available which includes ready-to-use liquids and slow-release granules and pellets.

Vitax Vitafeed Multipurpose Feed (Vitax)   
N:P:K 19-19-19   
Equal proportions of NPK plus trace elements, can be used all around the garden.

Vitax Q4 (Vitax)
N:P:K 5.3-7.5-10 plus trace elements   
All-purpose plant food, available in a pelleted form.

Westland Feed-All Soluble Plant Food (Westland)
 N:P:K 15-5-30 plus trace elements   
All-purpose soluble plant food, also available as a slow-release feed in  granular and tablet form.

Blood, Fish and Bone (Vitax, Westland)   
N:P:K 5-5-6   
General purpose ground feed that releases nutrients slowly.

Osmocote Controlled-Release Plant Food (Scotts)    
N:P:K 10-11-18 plus magnesium and trace elements    
Controlled-release action releases nutrients for up to six months.

Poultry/chicken manure (Vitax, Westland, Rooster)  
Tends to be slightly higher in nitrogen
All-purpose pelleted chicken manure good for enriching soil.

Also try: Westland’s Nutri Plant Feed, Chempak No 3 Fully Balanced Feed, VitalEarth Plant Food, Miracle-Gro Organic Choice All-purpose Plant Food, Miracle-Gro Singles, Miracle-Gro Controlled Release Plant Food.

‘SPECIAL’ FERTILISERS

FRUIT AND VEG
Fertilisers for fruit and veg tend to have higher levels of potassium, for more flowers, better yields and flavour.

Levington Tomorite (Scotts)
N:P:K 4-4.5-8 with magnesium   
High potassium for tomatoes and flowering pot plants.

Vitax Liquid Tomato Feed (Vitax)
N:P:K 4.5-4-5.9   
High potassium for good crops of tomatoes.

Phostrogen Liquid Tomato Food (Bayer Garden)  
N:P:K 4-2.5-8  
High potassium formula plus calcium to help prevent blossom end rot.

Organic Strawberry Feed (Vitax)  
N:P:K 4-2.5-8 
Formulated to increase your strawberry harvest. Can also be used on other soft fruit.

Organic Potato Fertiliser (Vitax)
N:P:K 4-2-6   
Formulated for sustained growth of potato tubers. Can be used on other veg crops.

Also try: Westland’s Nutri Tomato Feed and Nutri Fruit & Vegetable Feed, Westland Organic Potato & Vegetable Feed, Miracle-Gro Organic Choice Fruit & Vegetables Plant Food

ROSES
Magnesium is especially important for roses – a good rose feed will include it so it’s always worth using a special rose fertiliser
rather than a general one to keep your roses healthy.

Toprose (Bayer Garden)   
N:P:K 5-6-12 plus magnesium and iron   
Balance of nutrients plus iron and magnesium to guard against leaf drop.

Miracle-Gro Rose ‘Plus’ (Scotts)
N:P:K 10-7-10 with magnesium   
Ready-to-use granules with magnesium for healthy leaves.

Vitax Organic Rose Food (Vitax)
N:P:K 5-2.5-8.5 plus magnesium   
Made from poultry manure with potash and magnesium for healthy green leaves.

Also try: Chempak Rose Food, Greenacres’ NutraRose Micro

LAWNS
There are a lot of multi-purpose lawn products – feed and weed, feed, weed and mosskillers – but if you just want a straight high-nitrogen feed for giving your grass a boost in the spring, these will do the trick.

Evergreen Complete  
Feeds lawns, kills weeds and controls moss. Extra nitrogen greens up grass.

Westland Lawn Feed, Weed and Mosskiller   
N:P:K 12-2-4
Encourages green, healthy grass growth and kills weeds

Lawn Food & Tonic (Bayer Garden)   
N:P:K 38-5-5
Fast-acting, high-nitrogen soluble lawn food and tonic.

Miracle-Gro Liquafeed Lush Lawn Food   
N:P:K 12-4-8
Starter kit and refills available – the dispenser connects to your hose for easy application without mixing or mess.

Also try: Westland Aftercut Lawn Feed & Conditioner, Greenacres’ NutraGreen Micro, NutraGreen Lawn Micro and NutraGrass Micro, VitalEarth for Lawns, Evergreen Cut & Feed Lawn Feood, Evergreen Organic Choice Lawn Food.

ERICACEOUS
Ericaceous fertilisers normally include iron which prevents leaf yellowing and keeps your ericaceous plants in tip-top condition.

Miracle-Gro Azalea, Camellia & Rhododendron soluble Plant Food (Scotts)   
N:P:K 16-6-16 plus chelated iron, manganese, copper and zinc     Corrects leaf yellowing caused by iron deficiency, also available as slow-release pellets and as a liquid.

Levington Azalea, Camellia & Rhododendron ‘Plus’ Plant Food (Scotts)    N:P:K 7-7-17   
Granular plant food with magnesium and iron to prevent leaf yellowing.

Ericaceous Feed (Vitax)   
N:P:K 6-7.5-10.2 plus trace elements   
Convenient pellets for azaleas and rhododendrons.

Westland Rhododendron, Azalea & Camellia Plant Food
N:P:K 38-5-5   
Granular feed for applying direct to the soil. Also available as a liquid feed for diluting with water.

Also try: Chempak Ericaceous Fertiliser, Greenacres’ NutraAcid Micro, Miracle-Gro Organic Choice Azalea, Camellia & Rhododendron Plant Food

HOUSEPLANTS
There are plenty of feeds designed to give your house plants a treat and even more specialist ones for specific plants.

Baby Bio Original
 N:P:K 10.6-4.4-1.7    
The original houseplant food for diluting with water, but also comes in a ready-to-use bottle.

Also try: Baby Bio Orchid Food, Baby Bio Citrus Food, Westland Indoor Plant Food, Vitax Houseplant Liquid Feed, Vitax Orchid Bloom Feed & Orchid Growth Feed, Vitax Citrus Feed for summer and winter use, Global Citrus Summer and Winter Food, Chempak African Violet Fertiliser, Vitax African Violet Feed, Chempak Bonsai Tree Fertiliser, Chempak Cactus and Succulent Fertiliser.

‘STRAIGHT’ FERTILISERS

Bonemeal (Vitax, Westland)
N:P:K 3.5-20-0   
Not quite a ‘straight’ because it also contains a small amount of nitrogen, but this slow-release fertiliser is
high in phosphorus for good root development.

Dried blood (Vitax)
N:P:K 12-0-0   
High in nitrogen so great for healthy growth and leaves
– perfect for leafy crops such as lettuce or cabbage.

Sulphate of Ammonia (Vitax, Westland)
N:P:K 20-0-0   
Fast-acting source of nitrogen, perfect for leafy crops such as brassicas. Can also be used to green up your lawn.

Super Phosphate (Vitax, Westland)
N:P:K 0-17-0   
Phosphorus rich to encourage strong root growth and healthy plants. Can also be used to ripen wood, hardening up new growth and encouraging flowers.

Sulphate of Potash (Vitax, Westland)   
High in potassium   
Promotes flower development and higher fruit yields.

Also try: Chempak No 2 – High Nitrogen Feed and Chempak No 4 – High Potash Feed.

What’s the difference?
Slow-release fertilisers are slow release because it takes a while for the nutrients to become available to the plants’ roots but when they are, they are released in a burst; they last for a month, approximately.

Controlled-released are ‘clever’ fertilisers that release their nutrients slowly and evenly over a longer period – some are six-month, some are 12-month release. They’re great if you have trouble remembering to feed regularly! Confusingly, some manufacturers call their controlled-release feeds slow-release! Just look for ones that state how long they last, e.g. “one feeds lasts six months”.