Plant Nutrition Unpacked: Plant Nutrients and Deficiencies

 PLANT NUTRITION UNPACKED

Major Nutrients

Have you ever asked yourself "how do plants take up nutrients when you spread fertiliser around them on the ground or dilute it into liquid ?"

It's something that we gardeners do quite a lot of,  spreading fertiliser around that is, and probably don't give it a second thought until plants don't respond to all this nutrient load.

• What went wrong? 

Firstly, the nutrients that you spread around are not directly taken up by the plants.

Nutrients have to be what's called 'made available' to the plants and to do this, the soil biota or the microorganisms have to do some work.

Water, soil and microbes are the three things that the plants need before plants can take these nutrients.

• So What Are These Nutrients?

Macro Nutrients:   these are the highest rated nutrients that plants can’t do without.

• Nitrogen:Phosphorus:Potassium or NPK: 

  

  A selection of fertilisers

• Kylie's main mantra is NPK refers to shoots:roots;fruit

The N component relates as Nitrogen, giving your plant nice healthy green leaves.

The P component: encourages healthy root systems.

The K or potassium component helps the fruits and flowers

Sure we can add compost, aged manures and liquid seaweed, but unless you’re sure of what’s in them nutrient wise, you may be under fertilising your plants.

Without the major nutrients, your plants may not grow and develop roots, stems leaves and flowers properly.

If you know what and how much to give your plants, the plants will be healthier and more productive.

Just remember to read the NPK amounts on the bag or packet of fertiliser.
Let’s find out more about what plants really need.
I'm talking with Kylie Last, horticulturist and TAFE teacher.


If you have any feedback email realworldgardener@gmail.com or write in to 2RRR PO Box 644 Gladesville NSW 1675

PLANT DEFICIENCIES:

Imagine this scenario, you’ve fertilised your garden with all the right stuff, having followed the manufacturer’s instructions to a ‘t.’

But still the plants look sickly, or perhaps a bit yellow, or they’re just not putting on any growth.
Does that sound familiar?

• So what’s the problem?

The first thing you need to do is a pH test on your soil-there's no escaping it.

Why?

The soil pH will determine the availability pf different nutrients to your plants.

Let's look at an example

Looking at the chart on the right, it's immediately apparent that if your pH is higher than say pH7.5, then nutrients like iron start to taper off in their availability to the plant.

Then means your plant may start to show symptoms of iron deficiency.

In fact, after pH 7.5, other nutrients taper off in their availability, such as manganese, boron, and more importantly, one of the macro nutrients being potassium.

Basic pH test kit

 

• 
  Ideally the ideal pH range that gardeners should strive for is pH 6 - 7.5
• This is the range that the major nutrients of NPK are available to the plant the most.
• Some plants such as rhododenrons and azaleas like a like a low of pH6.

A pH testing kit is essential in any gardener’s shed. Consider testing your soil in different parts of the garden.

A good tip when taking soil samples from your soil is to get a sample from just below the surface for an accurate reading.

 

First signs of Nutrient Deficiencies: 

Nitrogen: new leaves are pale green and older leaves are yellow and start to dry up.

Phosphorus: purpling of the leaves, particularly along the lower leaves. New leaves are a bit stunted and deformed in severe cases.  A bit more rare.

Potassium: poor overall health; older leaves turn yellow then crisp up and die off. Often mistaken for dehydration.

Let’s find out more about  pH testing and plant deficiencies 
I'm talking with Kylie Last, horticulturist and TAFE teacher.

If you have any feedback email realworldgardener@gmail.com or write in to 2RRR PO Box 644 Gladesville NSW 1675