Urban Food Garden

FERTILISING VEGEGATBLE BEDS 3

Fertilsing Vegetable Beds

How much fertiliser should be added to a vegetable bed depends on three things: 

  1. THE VARIETY OF VEGETABLE BEING GROWN
  2. THE TYPE AND STRENGTH OF THE FERTILISER BEING APPLIED
  3.  THE CURRENT HEALTH OF THE  SOIL IN THE VEGETABLE BED

Given these variables it is easy for a gardener to apply either too much or too little fertiliser.  This page lists five different standardised fertiliser application rates, depending on the vegetable varieties being grown. 

But note that every garden has its own soil type and conditions which may require different fertiliser application rates,  as such the recommendations below should only be seen as a rough guideline.

TERMINOLOGY
  • All amounts listed are for per square metre (m²) of garden bed.

     

  • ANIMAL MANURE refers to sheep, horse and cow manure.  If you are using chicken manure than halve the amount as it is very high in nitrogen, but only use well rotted chicken manure or Dynamic Lifter (compressed pellets of chicken manure with other additives) as fresh chicken manure can burn vegetables.

     

  • LIQUID FERTILISER is diluted liquid fertiliser concentrate such as worm juice (liquid worm castings), Seasol (liquid seaweed), PowerFeed  (made from fish fertilizer and concentrated liquid composts), or you can make up your own concentrate by soaking various fertilisers in a drum of water.

     

  • ROCK DUST is powdered rock containing trace elements beneficial to your garden.

     

  • LIME is used to raise the pH of the soil.

     

  • NPK refers to nitrogen (N), phosphorus (P) and potassium (K). It is a balanced macro-nutrients application used in inorganic gardening.  While I do not recommend only using inorganic fertilisers they are listed here as an optional extra low dose supplement.  There are more specific inorganic fertilisers, such as potash or urea, but for simplicity I have mainly listed NPK fertiliser.
 
STANDARD VEGETABLES

VEGETABLES: Tomato, lettuce, cucumber, corn, plus any vegetables not listed in the other categories.

BASIC APPLICATION (m²)

  1. SHOVELFUL OF ANIMAL MANURE
  2. SHOVELFUL OF GOOD COMPOST
    If you do not have good compost available then replace with a 1/2 shovelful of manure.
  3. HANDFUL OF BLOOD AND BONE

OPTIONAL EXTRA

  • PINCH OF ROCK DUST
  • 1/3 HANDFUL OF NPK FERTILISER
    No more than half the recommended dose on the packet, can be added as extra or used to replace some of the animal manure.
LIGHT FEEDER VEGETABLES

VEGETABLES: Carrots, beetroot

BASIC APPLICATION (m²)

  1. NOTHING!
OPTIONAL EXTRA
  • PINCH OF ROCK DUST
  • 1/4 HANDFUL OF NPK FERTILISER
  • HANDFUL OF BLOOD AND BONE

NOTES
As long as the soil in your garden bed is in good condition then there is no need to add fertiliser.  Adding manures and compost can actually be detrimental to carrots as it can result in split roots. 

HEAVY FEEDER VEGETABLES

VEGETABLES: Capsicum, eggplant, celery and pak choi.

BASIC APPLICATION (m²)

  1. SHOVELFUL OF ANIMAL MANURE
  2. SHOVELFUL OF GOOD COMPOST
    If you do not have good compost available then replace with 1/2 shovelful of manure.
  3. HANDFUL OF BLOOD AND BONE
  4. FOLLOWUP APPLICATIONS OF LIQUID FERTILISER
    Apply every one or two weeks, especially when the fruit is maturing.
OPTIONAL EXTRA
  • PINCH OF ROCK DUST
  • 1/3 HANDFUL OF NPK FERTILISER
    No more than half the recommended dose on the packet, can be added as extra or used to replace some of the animal manure.

NOTES
This is the same dose as the STANDARD APPLICATION, the difference being you are also regularly applying liquid fertiliser.

ALKALI SOIL LOVING VEGETABLES

VEGETABLES: Broccoli, cabbage, cauliflower, Brussels sprouts, beans and peas.

BASIC APPLICATION (m²)

  1. 1/2 SHOVELFUL OF ANIMAL MANURE
  2. SHOVELFUL OF GOOD COMPOST

    If you do not have good compost available then leave it out.

  3. TWO HANDFULS OF BLOOD AND BONE
  4. HANDFUL OF LIME

OPTIONAL EXTRA

  • PINCH OF ROCK DUST
  • 1/2 HANDFUL OF NPK OR POTASH FERTILISER
    No more than two thirds the recommended dose on the packet, can be added as extra or used to replace some of the animal manure.
  • FOLLOWUP APPLICATIONS OF POTASH
    Apply by mixing the recommended dose of potash in a watering can and water in.  For brassicas, apply  two or three times over the life of the plants, you should not need to apply potash to peas.

NOTES
The lime is to make the soil more alkali and to counter the acidity of the animal manure, hence the reason for adding less manure.  But if you live in an area that has naturally alkali soils you might need to use less lime.  Conversely, you might need to add more if your soil is very acidic.  The ideal pH for these vegetables is 7.0 (neutral) or slightly above. 

LARGE SPREADING VEGETABLES

VEGETABLES: Pumpkin, zucchini and squash.

BASIC APPLICATION (m²)

  1. SHOVELFUL OF ANIMAL MANURE
  2. SHOVELFUL OF GOOD COMPOST
    If you do not have good compost available then replace with 1/2 shovelful of manure.
  3. HANDFUL OF BLOOD AND BONE

OPTIONAL EXTRA

  • PINCH OF ROCK DUST
  • 1/3 HANDFUL OF NPK FERTILISER
    No more than half the recommended dose on the packet, can be added as extra or used to replace some of the animal manure.

NOTES
This is the same dose as the STANDARD APPLICATION, the difference is in how it is applied.  For pumpkin:  Dig a hole about 30 cm deep and 100 cm wide.  Add two thirds of the manure/fertiliser (the same amount that you would add evenly to a square metre) to the hole, then cover it with a mixture of soil and the rest of the manure to make a mound slightly higher than ground level. Plant two pumpkin seedlings (or seeds) on top of the mound.  The same applies for zucchini, but with about half the dose and two thirds of the space.

A standard shovelful of manure.

A handful of blood and bone.  A “handful” will vary depending on the size of the person’s hand.  The general rule of thumb is it should be about 100 grams.

These recommended fertiliser doses should only ever be seen as a rough guideline. Every gardener will have different views of what fertilisers to use, how much to apply and when to apply it.  But  whatever you use it should be applied in measured doses appropriate to the vegetables being planted.  Shoveling fertilisers on haphazardly is not good gardening practice.

Also note that there is more to creating good soil than simply adding fertilisers.  It is a good practice to cover your beds with mulch (at least in the warmer months) and then turning that mulch in when preparing the bed for a new crop in order to add organic matter.  Fallowing beds and practicing crop rotation will also improve the quality of your soil and plant growth.

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