Often there are not enough nutrients existing in the soil as through growing we keep taking out without any naturally being put back in.  So there is a need to feed!  By applying fertilisers you'll be topping up the soil to help keep it full of nutrients. 

You Should Use Organic Fertiliser!

Well there are both organic and inorganic options.  However, we’ll only talk about organic, those that are from natural sources like plants, animals or naturally occurring rock.  In addition to providing nutrients, these increase the organic content of the soil, improve its physical structure and the increase of bacterial activity which makes other nutrients more available to plants.  Organic fertilizer also naturally slow-releases nutrients as the soil micro organisms need time to break down substances into forms that plants can use.  Non-organic fertilizers however are so concentrated that over time they create imbalances in the soil that reduce the all-important microbial and earthworm activity.

Organic fertilisers come either as a 'compound' fertiliser which contains a mix of the three major nutrients (Nitrogen, Phosphate or Pottassium - NPK) in varying proportions, or as a 'straight' fertiliser which is only a major nutrient on its own.

By law, the amounts of nitrogen, phosphorus and potassium contained by a fertilizer must be stated on the package. So if a package is labeled 6:4;4 it means that in every 100 grams of fertilizer, there is 6 grams of nitrogen (N) and 4 grams each of phosphorus (P) and potassium (K).  The order of numbers will always be NPK.  Care should be taken when handling ANY fertiliser and the instructions on the packets should be followed strictly. Using too much can upset the balance of the soil and damage plants by burning them, besides which, it is an unnecessary waste of money.

Types of Fertiliser

Fertilisers can either be applied whilst preparing the soil pre-growing (base dressing) or during the plant growth stages (top dressing) to boost plant development.  When applied to the soil either prior to or during the growing season, it can be done via dry/granulated material or as a liquid for uptake by plant roots.  In addition to fertilising the soil, directly feeding plant foliage through a spray (foliar feeding) is a great way of correcting either a major or minor nutrient deficiency.

  • Organic Solid Feed Fertiliser - The most common type of fertiliser that is available in granules or powder form.  Can be forked into the soil lightly prior to sowing or planting (“base dressing”) but also added during the growing season as a top up (“top dressing”).  Make sure you water the feed in well to make the nutrients available to the plants.
  • Liquid Feed Fertiliser (great for containers!) - These come in a variety of different formulations, including complete and incomplete. All are made to be diluted with water; some are concentrated liquids themselves, while others are powder or pellets. They are particularly effective as a one-time application procedure at the point when you have first planted directly into the soil.  By doing so they provide an immediately available supply of nutrients for fast root growth and plant establishment.
  • Foliar Feeding - This is an emergency tactic for feeding nutrients to the plant.  There may be a need to correct a deficiency in either a major or minor nutrient; to counteract the use of an insufficient soil fertiliser applied at the beginning of the growing season; or as a way of quickly feeding nutrients to the plant when cold weather prevents the soil fertilising from working.  Application is via a spray to the foliage where nutrients begin to absorb directly through the leaf surface in minutes and completes in 1-2 days.  Be sure to use foliar feed in addition to fertilizing the soil, never as a replacement because too many applications would be needed to have an equal affect.  Also be sure to follow directions carefully - using too much fertilizer can quickly burn the foliage.  

Golden Rule - when feeding the soil, always make sure the soil is moist and the soil temperature is warm enough.  These are the conditions needed for the soil organisms to be active in order to break down the organic fertilizers and release the nutrients. 

So far as the methods of applying fertilizer are concerned, this depends on its formulation and the crop needs.  Always read instructions on the packet carefully before you start.   

Other Soil Conditioning Tips

Having fertilized at the beginning of the growing season, another piece of sound advice is to apply organic matter on top of the soil.  A layer of wheat straw , leaf mould , compost or well-rotted manure will play an important role in soil structure, drainage and its ability to retain nutrients - Strulch an organic garden mulch is perfect for this.

Seaweed plant feed is a 100% organic resource that is well worth thinking about.  It increases plants’ ability to absorb nutrients and improves root growth and leaf cell structure – making crops better able to cope with conditions brought on by drought.  This process increases the number of microbes present in the spoil, which help to speed up the breakdown of organic matter and making existing nutrients more readily available to growing crops.

How Much Fertiliser?

The amount of fertilizer and its frequency of application depends on:

  1. the natural fertility of the soil – check using a soil testing kit
  2. the type of fertilizer being used and its release rate – see the packet of what you have bought
  3. the type of vegetables being grown – see the What to Grow section.

TOP TIP - For years, gardeners have been using hand-made grid squares to help apply fertilizer accurately. This isn’t difficult and you don’t have to be a whizz at DIY to make either a metre or yard square – four pieces of wood cut to size and nailed or screwed together is about as difficult as it gets – which you can place on a section of your soil and then evenly scatter the fertilizer over. You’ll need to measure out the correct amount of fertilizer beforehand (enlist the help of a small set of scales and a plastic cup or container), details of which you can find on the packet. Then you can carry on using the square, moving it as you go – or if you’re feeling confident, ‘guesstimate’ the rest of your bed based on the square you marked out.