How often to use fertiliser?

Good garden soil will give your plants everything they need to help with optimal growth and quality harvests. As micro-organisms in the soil break down fallen plant matter, they release different nutrients that become available to our plants to absorb. 

As we harvest our plants and tend to our gardens though, we don’t let as much plant matter get down to the soil, and this can mean fewer nutrients being made available in the soil. 

So how do we ensure that our garden soil gets all the nutrients that our plants need? The obvious way is to add high-quality fertiliser, like Arktivate, to our garden beds, and you’re likely to notice the difference it can make pretty quickly. But when and how often should you use it?

We’ve got some helpful points to consider when you’re deciding just how often you should use fertiliser in your garden. 

Different Types of Fertilisers

One of the most important points to learn about fertilisers early on is the many different forms they can come in and how the different types work to deliver nutrients to the plant.

When we understand what they are and how they work, we can better decide when we should use them, and how often.

Organic material fertilisers

These fertilisers are broken down from natural organic materials from plants or animal waste products, the most common form being humble manure. They’re rich in the three main nutrients plants require; Nitrogen(N), Phosphorus(P) Potassium(K), but can contain trace elements as well.

Different types of organic fertilisers will have different concentrations of each nutrient. Though, with some products, you may not be able to tell exactly the content of each nutrient.

The biggest benefit to organic fertilisers is the presence of microbes that create a sustainable ecosystem for your plants’ long term growth.

Inorganic fertilisers

These are fertilisers that have been manufactured from mined or synthesized materials. They can come in both powder and liquid forms.

They’re designed to be immediately available to your plants and take less incorporating than organic fertilisers, so are very fast-acting.

Because they are manufactured, you can narrow in on the exact nutrient you want to apply. Inorganic fertilisers generally come as an NPK blend, with different rations to suit different situations.

Be careful, as adding too many nutrients put your plants at risk of a burn from the fertiliser.

Slow-release fertilisers

These inorganic fertilisers come in small pellets that have a special coating that slowly breaks down as they are exposed to moisture. As they dissolve, these layers release a small amount of nutrients into the soil. 

This process can last several months and provide a sustained supply of nutrients to your plants.

As slow-release fertilisers are inorganic, you can purchase blends specific to you. They also remove the need for ongoing applications over a season. However, they do not create a sustainable environment for your plants like Microbes do.

Best times to use fertilisers

The best time to use fertilisers in your garden is when your plants need them. This sounds simple, but it does take a bit of planning and knowledge on your behalf to get it right.

For annuals

If you’re based in a place with all four seasons, i.e. not in Singapore, and you’re growing annual plants, the best time to apply an organic fertiliser is before your plants begin to grow.

Applying an organic fertiliser before you plant seedlings, or as your seeds begin to germinate lets the microorganisms in your soil break down the organic material in the fertiliser. This means that the nutrients are available when your plants start to grow.

You may apply inorganic fertilisers as you plant seedlings or after your seeds have germinated so that nutrients are available for use straight away, but it’s better to plan ahead and create a suitable environment for plant growth using organic fertilisers.

Follow-up applications of liquid fertiliser with trace elements can help your annuals when they’re ready to flower or develop fruit. 

For perennials

The best time to fertilize perennials is when they come out of their winter dormancy in spring. This is when your plants will put on new growth and their focus shifts to flowering and fruit production.

Your plants are working their hardest during this time, so a good supply of nutrients can help keep them healthy. Trace elements can also help with issues like leaf yellowing that can develop as plants throw all their energy and resources at flowering. 

You can apply a liquid organic or granular inorganic fertiliser or use a slow-release fertiliser scattered just below the top layer of soil in your garden. You can also apply organic mulch or manure and scratch it into the top layer of your garden bed. 

Weather conditions

An important consideration for the best times to apply fertiliser is your local weather forecast. 

To avoid accidentally burning your plants, never apply a liquid or powder fertiliser on or just before a hot dry day, and always water in any fertiliser. Watering also helps keep powdered fertiliser where you want it, and not be blown away in wind. 

Try to line up your fertilizing with forecast rains to save you the hassle of watering it yourself. The deep gentle watering of rain will pull all the nutrients deep into the root zone of your plants.

How often should you use fertiliser then?

Now that we know the types of fertilisers and the best times to use them, how often should you use them?

We know that different fertilisers will work in different ways and the variety of nutrients available to buy can mean you can use them to solve different issues with your plants. But there are problems with overuse.

How often you should fertilize will all come down to a few things. 

• What plants you’re trying to grow.
• The condition of the soil they’re planted in.
• The history of what has been planted there before.
• The amount and type of fertiliser you have access to.

You’ll also need to consider your local weather conditions and plan around any wet or dry seasons that your garden experiences.

If your soil is already in good condition, then you shouldn’t need to add too much fertiliser. Applying an organic fertiliser once a year and a sprinkle of slow-release trace elements if your plant starts suffering from a deficiency will do the job.

If your soil does need some help, then start small. Applying too much fertiliser can encourage unwanted growth of foliage, flowers, or fruit, which can impact the quality of your plant’s health and harvests that season. 

Therefore, you should limit inorganic NPK fertilisers, and only apply trace element blends when your plants need them. Better still, sticking to organic fertilisers only, especially ones that contain trillions of microbes, will ensure a sustainable long term growth of your plants and the healthiness of the soil.

So while fertilizing seems like a great way to really kick on your plant’s growth, it’s actually better to ease off the pedal, take a more reserved approach, and only apply it when you know it definitely needs it.