Is Fertilizer needed in a Food Garden: is fertilizing a waste of time?

organic fertilizer for growing food

To begin with, we should define what a food garden looks like so we can be understood. We are qualified Permaculture Designers who trial and test our ideas on our own system or yard as you might call it.

We call it a system because it is a carefully designed edible ecosystem where each item or element has multiple uses and benefits. This includes fruit trees, vegetable garden beds, structures for vines to climb, and many self-sowing varieties of herbs and spices.

This system is deliberately designed heavily with perennials to give stability in yield and to allow work effort to be utilized efficiently for maximum output.

It is through this lens that we write this article. Do you need to fertilize your garden? Let’s find out.

Why do we fertilize vegetables?

You will often want to lift the yield and quality of the plants, and the reasons to fertilize vegetables can be many, however the expected results are very similar i.e. you apply vegetable fertilizer to get a better crop or harvest from the garden.

What style of fertilizer is best for gardening?

There are several forms of fertilizer available and they all share the same intended design of supplying nutrients to plants. While they all fertilize, they achieve it through different mechanisms that we choose to best use when gardening.

The forms most common to us are listed here.

  • Granular
  • Powder
  • Liquid
  • Pelleted

These types of vegetable garden fertilizers are designed to be used in certain situations. The liquid form is great for foliar feeding, where the granular and pelleted are often slow release where you can use over an extended period to supply nutrients.

organic fertilizer in liquid form
Follow the directions for foliar applications

Long croppers like tomatoes can benefit from the slow release as you pick daily.

Granular can be similar to the above but some have soluble cases that dissolve with moisture contact, and these can deliver all the nutrients all at once.

Powdered forms can be watered in to the soil, or premixed and applied with watering cans.

Are fertilizers harmful or beneficial in the garden?

The variety of vegetable fertilizer that is used will determine if it has any detrimental effects to your vegetable garden in the short term. This is where soil type and soil condition come into the equation.

The question cannot be answered in a one-size-fits-all comment as there are so many variables to take into consideration.

Different soil types respond best when matched to suitable methods of applying fertilizers.

Sandy garden soil is very difficult to hold nutrients in the root zone before they wash lower into the sand. This can lead to more frequent applications hoping to fertilize the vegetables.

Sandy soil can be expensive to grow in if you buy all your nutrient needs each season. You can spend a lot of time and money trying to feed the veggies as the nutrients wash past the vegetable roots.

Clay soils can hold the fertilizers above the ground and the vegetable roots can have difficulty accessing the nutrients. The obvious garden soil type to aim for is one that is rich in organic matter.

This allows nutrient passage and holds moisture simultaneously. It also hold the most chance of good populations of beneficial micro-organisms.

How can fertilizers be harmful?

If fertilizer is applied at the incorrect dose or rate, this can either starve or overfeed the plant. It is easy to apply ‘just a little bit more’ to get a bumper crop and have all the fertilized plants fail.

This overfeeding can limit the harvest of certain vegetables like sweet potato if the fertilizer contains too much nitrogen.

Excess nitrogen will promote excessive leaf growth to the detriment of tuber growth. In the sweet potato case, the plant will look fantastic with vigorous leaf growth, but all the energy is towards leaves and not the potato crop we expect.

Heavy rainfall can be harmful if a granular fertilizer is applied before the rain. This can take the fertilizer from the area you where want it and wash it somewhere unproductive. This can be costly, both in vegetable yield and fertilizer expense.

Do all types of vegetable need fertilizing?

To grow a plant, you do not need to apply fertilizer but to grow a harvest you need to feed your plants.

Plants should respond to an appropriate application of fertilizer, however, there is far more to this story than first meets the eye. Suppose you are gardening and decide to plant out a vegetable garden but you don’t have any fertilizer available.

Do you choose not to plant the garden? Or do you still go ahead and see if you can get a vegetable return from the garden.

I highlight the above question because if you look at the areas of wild growth around your area, fertilizers are not applied here and yet the plants continue to grow happily. The seed crops or fruit that these wild plants grow are from natural processes, but they often yield small quantities.

The point I am making is that plants can and do grow without fertilizers in a natural setting.

Does this mean fertilizing is not needed?

Not at all. All plants need nutrients; how these nutrients are supplied is the question. To look at this objectively as gardeners, consider this… we often grow a single variety of vegetable in a garden bed, and in this situation any supporting conditions for that plant that are typically present in the wild areas are not present.

To reliably obtain a harvest we somehow need to supply these supporting conditions, because obtaining a harvest is the end game, or it should be. It is in our personal case.

What conditions can fertilizer replace?

A well-designed fertilizer is intended to supply the macro-nutrients that are present in the natural growing conditions preferred by that plant.

Many micro-nutrients are missing from fertilizer, so we rely on quality soil to supply these. How to obtain this is another topic that we have experience in, and this article details how we go about it.

nutrient list in fertilizer
Nutrients should be balanced

Each plant variety has its own requirements, so this is where we look to the conditions that are present where a wild version of the plant happily grows.

There may be a particular soil type involved that has the required minerals and trace elements available in appropriate quantities. The plant may grow alongside other plants that help feed the plant through localized mulch.

All of these factors supply our target plant with what is needed for healthy growth. A well-designed fertilizer can supply some of these nutrients.

What fertilizer cannot do.

Climatic conditions play a major part when growing plants, particularly food growing; and are vital in a self-sufficient garden such as ours.

Fertilizer cannot do anything for the gardener outside of supplying some nutrients. Fertilizer cannot supply any moisture retention benefits to your soil either. This is because they are lifeless and sterile.

Can fertilizing help improve soil structure?

Organic fertilizers can help soil structure through the actions of beneficial microbes already in the soil.

These organic fertilizers become activated by biological activity and are suited to soils that are already rich in organic matter and are well mulched. Worm numbers and activity should increase after this kind of fertilizer is applied.

When is it best to Fertilize Garden Vegetables?

The best time for fertilizing garden vegetables is when the plants have several leaves on them. Some fertilizers can damage very young seedlings, so it is best to wait until the plants are several inches tall. The information on the fertilizer label should guide you with this.

when to apply fertilizer
Read the label for instructions on applying fertilizer

If you fertilize right before planting, be sure to apply it some distance from the seedling or seed so germinating seeds or young roots don’t find it to early.

What time of the day is suitable to apply vegetable fertilizer?

The coolest hours of the day are the best times to apply fertilizers. The heat of the day should be avoided so as not to stress the plants. Many fertilizers are water soluble and can be foliar-applied and these have the potential to harm leaves if they are sprayed in hot weather.

Do you need to use a vegetable fertilizer schedule?

In some cases, a vegetable fertilizer schedule can be beneficial. We don’t use one ourselves as it all starts to become too complex to manage all the different fertilizers out there.

Here where we live, we think that we can treat every vegetable the same if we can offer the vegetable every nutrient it requires, when it needs it.

This is a very different concept to manufactured fertilizers that basically force feed the plant a nutrient soup. Each vegetable will require its own recipe of nutrients so this is why you find there are so many nutrient ratios on the separate fertilizer packets.

We fertilize our gardens with nutrients from the chicken pen, composted cow manure, fermented plant material, and our compost for self-sufficient gardening mix.

This serves several purposes simultaneously including cost effectiveness, availability, and being naturally derived so we can trust its safety in our soil.

If you have designed well you can keep the nutrients in a constant loop that cycles through your site year after year, and this is the best outcome. This is how we approach permaculture design, and we’ve never had a growing vegetable complain yet!

Do all plants in the garden need Fertilizing?

All plants need nutrients but not every vegetable needs fertilizing. Some gardeners work on improving soil structure through applying composts and other organic material, and this can be enough to grow some plants without and intervention by the gardener.

Many perennial plants are well suited to life without fertilizing and can produce fruit or seeds each year without any inputs at all. We apply mulch to garden beds where these perennials grow all the time, and they do well with just this little bit of attention.

Do fruit trees need fertilizing?

In some situations, similar to the vegetable, you have fruit trees that can benefit from appropriate fertilizers, however the timing and the application need to be thought out before the fertilizer is applied.

Poor timing or nutrient concentration can be wasteful and can even cause the fruit to drop. Hint… apply carefully.

We have many fruit trees in our system, and we never fertilize them. We have understory plants that grow in harmony with the trees, and some mulch is all we ever do. The mulch is usually woody and thick and as it breaks down in the garden it is fertilizing the trees naturally.

This approach allows us to obtain a regular fruit harvest with very little input, and we don’t have to be concerned about stressing the trees from a dressing of chemical based steroids, which is, technically speaking, what fertilizing is.

What if you want to fertilize organically. Is it possible?

Thanks to market pressure you now have choices of what kind of fertilizer you can use. There are two main kinds of fertilizer available for the gardener to use…

  • Organic fertilizer.
  • Inorganic fertilizer.

Both kinds can be in a variety of forms as noted earlier.

What are organic fertilizers?

These fertilizers are a method of supplying required nutrients to plants via microbial activity. This activity is takes place in the garden at the root-zone soil-surface interface and is a direct result from having compost and mulch as part of the garden soil building process.

slow-release organic fertilizer
Organic slow-release fertilizer

Some gardeners assume that composts are fertilizers, and it is easy to understand the error. While composts are definitely organic, they are more of a microbiology transfusion into your soil rather than being a useful source of nutrients.

Composts do hold nutrients, but relying on assumed quantities can be a mistake.

How are inorganic fertilizers different to organic?

Inorganic fertilizers are chemical blends that need moisture to be activated as they have a salt-based casing that dissolves with moisture.

They are manufactured and are lifeless and are available in precision ratios to give particular plants the required nutrients for flowering, fruiting, and leaf growth. The fertilizing industry has created a product to fertilize every vegetable.

There are risks to your soil health associated with long-term use with inorganic fertilizers. They are a result of the way the fertilizers work and how they are activated.

It is something to be aware of, and we felt the topic warranted its own article versus compost. You can find it here.

What alternatives for the vegetable grower is there to using fertilizer?

There are few viable alternatives to fertilizer if you are looking to grow reliable harvests. It comes down to how active you are prepared to be in the vegetable garden and how you approach the world of convenience.

Chemical inorganic fertilizers are marketed to the grower looking for results with little spare time, or little knowledge in how these products work. While they do deliver results, you will always have your hand in your pocket pulling out cash.

Then there is the potential for long term harm to your soil if continual use is your way of vegetable growing.

Suppose you were to fertilize every two weeks as some brands suggest, and the soil is clay based; there is a high probability that the chemicals used to stabilize the fertilizer will slowly build up over time and become toxic in the soil.

This is not an outcome we suggest aiming for.

We fertilize with animal manures, both composted, and aged. We also engineer our composts to a standard equal to or better than fertilizer quality and use it on fresh raised garden bed plantings.

With the vegetable garden then covered with mulch we have the nutrients in place with beneficial microbes to match, and the garden responds well. This proved to us that you don’t need commercial products to fertilize a vegetable.

How do we go about this process? It is one of those topics that could have an entire website dedicated to it (This website is but we are not done by a long shot), but for now all we can offer is this article explaining our compost process. There are a few surprises in there.

What are our vegetable garden fertilizer recommendations?

We understand that fertilizing means different things to people, and with so many ways of feeding vegetable gardens it can be confusing to beginners and experienced alike.

We can only recommend the methods we use to fertilize vegetables, as we have come to trust and accept the results we obtain as we plant out and harvest each year.

We will only apply organic methods to growing our vegetable supply because we see our efforts as a partnership with the life in the soil, and by doing so the return from our vegetables is measured in many ways.

It tastes great, it is nutrient dense, it contains no toxins, and the cost of growing is close to zero. We understand that each vegetable variety has different needs, and have found that good quality composts with local animal manures can be a sustainable way of fertilizing the garden.

We also use liquid fertilizer in the form of fish emulsion, and apply this as needed. It is derived from an environmentally destructive imported fish here in Australia, so using and supporting this product is beneficial environmentally.

In Summary.

One thing every vegetable grower has in common is the want to grow good amounts of healthy food, and sometimes fertilizer is required to achieve this result.

The question of fertilizing then comes down to the thoughts and beliefs of the individual gardener, and how natural do we want to be with applying fertilizers.

Fortunately, there are companies making organic fertilizers. With these we can work in tandem with our soil biology to achieve high yields and through this we can maximize the harvest from vegetable gardens.

Article by Tim Blanch for He is a qualified Permaculture designer.