Understanding Fertilizers

We all love to get fed. Whether it’s around the table at the holidays, or out of the town with your significant other, we often choose our food based on what’s appropriate for the occasion. Feeding your plants is not so different. While fertilizers can be intimidating, given all the options out there, it doesn’t have to be. Just like it is with feeding a person, it’s all about offering a balanced diet, feeding at the right time, and not overdoing it. Also like our human diets, there’s a LOT of junk out there, and it’s important to know how to avoid it!

Organic vs. Inorganic Fertilizers

When we’re shopping for our own groceries, we tend to think organic is better. When it comes to fertilizer, that’s not necessarily the case. Both types of fertilizers have distinct advantages and disadvantages, depending on what you’re trying to achieve with your plant food. Organic and inorganic quite simply refers to what the fertilizer formulation is made from.

Organics are made from decomposed matter, like compost and good old-fashioned manure.

Inorganics are engineered from straight nutrients, not unlike your daily multivitamin pill.

hand holding inorganic fertilizer

Pros and Cons of Inorganic Fertilizers

The multivitamin example is a good starting point for understanding why you might choose an inorganic over an organic. The benefits of inorganic fertilizers are:

  • They’re fast-acting – You’re delivering nutrients directly to your plant in an easy-to-absorb formulation.
  • They’re goal-oriented – The manufacturer can control the exact proportions of nitrogen, phosphorus, and potassium. This isn’t nearly as easy to control with organic fertilizers.

On the other hand, they aren’t really a complete solution for most gardens. Some of the drawbacks of inorganic fertilizers are:

  • They’re short-lived – Liquid fertilizers pass right through the soil and wash away easily with water, so they only offer plants a quick boost.
  • They leave no traces – Unlike a scoop of compost that integrates with the soil, liquid fertilizers pass through to the water table without leaving the soil any richer.
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Pros and Cons of Organic Fertilizers

If inorganic soils are a one-night stand – brief, satisfying, and then out of the picture – you could say organic soils stick around to put a ring on it.

  • They integrate with the soil – Solid organic fertilizers become one with your garden soil, enriching the soil quality in the long-term as they decompose.
  • They’re nurturing (to the planet, not just the soil) – Organics are made from all sorts of biodegradable materials, which means they’re more environmentally-friendly.

However, just because these fertilizers stick around, doesn’t mean it’s all happily-ever-after!

planting organic fertilizer to your plants
  • They aren’t as rich – It’s not that organics don’t contribute a lot over time, but they definitely can’t spoil your plants with nutrients like inorganics can.
  • Some are untrustworthy – If the fertilizer claims to be organic but doesn’t reveal the ingredients anywhere on the packaging, keep moving! You don’t want to introduce any unknowns to your beloved plants.

Since organics and inorganics offer complementary pros and cons, it’s usually a good strategy to incorporate both into your gardening strategy. (Remember, we’re still talking about fertilizers – we don’t recommend incorporating both into your relationship strategy.)

ammonium nitrate fertilizer

Making Sense of Fertilizer Labels

For those of us who weren’t so strong in chemistry, words like “nitrogen”, “phosphorus”, and “potassium” can bring on a little queasiness. Luckily, there’s an easy way to grasp what they all do – “up, down, and all around”.

Nitrogen, the “Up” – Nitrogen feeds the top parts of the plant – the stems and foliage. A fertilizer with a higher amount of nitrogen (like a 30-10-10) will give you lots of leaf growth, which can give plants that bushy, full look, but doesn’t really do much for flowering. Too little nitrogen looks like yellow, dull-looking leaves.

Phosphorus, the “Down” – Phosphorus feeds the plant roots, allowing root systems to grow vigorously. A higher-phosphate fertilizer (like 15-30-15) will help seedlings get established and promotes flowering.

Potassium, the “All Around” – Potassium – the last number – is like a supplement that helps your plant absorb all the micronutrients it needs to thrive. This ensures even, healthy growth.

For most purposes, an even 20-20-20 fertilizer is appropriate. With balanced levels of each nutrient, your plants should get a healthy dose of nutrition without too much of any one thing.

If you’re new to fertilizing plants, don’t be nervous! It all makes a lot of sense once you start reading the labels. Just make sure to follow the package instructions to the letter and your plants will be enjoying a satisfying meal in no time – no cooking required!