How to Fertilize Houseplants

Fertilize Houseplants

When it comes to plant caretaking, sunlight and water are instrumental to healthy growth. But what about fertilizer? Just like humans, plants need essential nutrients to help them grow, and that’s precisely what fertilizers provide.

Plant fertilizer is a natural or artificial substance that is added to soil to supply plant nutrients. It is not plant food. Plants produce their own food using sunlight in the process of photosynthesis.

The three main macronutrients in fertilizers are typically nitrogen, phosphorus and potassium. For this reason, you will see the letters NPK on fertilizer packages. Nitrogen helps with leaf growth, phosphorus develops roots, flowers, and seeds, and potassium with drought resistance. In a nutshell, fertilizers enhance overall soil fertility and improve plant growth.

Indoor plants especially need fertilizer because the natural nutrients it would get from direct sunlight and rain are limited. In the wild, plants are naturally fertilized by other means, like animal droppings and decomposition. Houseplants need our help.

It isn’t always easy to detect when plants need fertilizing, but practice makes perfect. Luckily and conveniently, nowadays, you can order plants right to your door, and retailers will give detailed instructions on how to care for your plants, including fertilizing properly. Not only that, but you can order wholesale indoor plants from sites like once you catch your plant groove. Here are the main things to consider when learning how best to fertilize house plants.

Types of Fertilizers

There are a variety of fertilizers: liquids, sticks, granules, tablets, and slow-release forms. The best fertilizers for indoor plants are liquid and slow-release forms.

Liquid fertilizers are the most common for indoor plants. They’re diluted and applied with a watering can. They’re easy to use. Liquid fertilizers are best for small plants or plants that need little feeding. When it comes to fertilizing, under-fertilizing is better than overfertilizing making diluted fertilizers beginner-friendly.

Slow-release forms are coated in time-release shells that slowly spread the nutrients throughout the soil. One can last a very long time, some lasting 3-6 months, as opposed to liquid fertilizers that require constant application.

When Should I Fertilize?

Knowing exactly when to fertilize your houseplants can get tricky. Just as overwatering and too much sunlight can damage plants, so can over-fertilizing. Too many nutrients cause what’s called “fertilizer burn.” Fertilizing should be done during the growing season: spring to summer. Around that time is when they grow actively, so they would benefit the most.

Each houseplant has specific needs, but a consistent schedule should do the trick. Depending on the fertilizer, you could have a biweekly or monthly schedule. Be sure to read the label and instructions on the fertilizer you purchase.

If the houseplant has been recently potted or repotted, it’s best to wait 2-3 months and allow the plants to make use of the fresh nutrients in the potting mix. If you’ve repotted in winter, wait until spring to fertilize.

Plants that grow faster should be fertilized more often as well as flowering and fruiting plants. Cacti and succulents should be limited to every 6 weeks.

How Should I Fertilize?

The best way is to dilute it. You should dilute liquid fertilizers in water with a 1:4 ratio. If applied daily, a 1:10 ratio is best. Watering your plants before fertilizing helps prevent burning, and moist soils optimize absorption.

What Do the Numbers Mean?

You will see three numbers on fertilizer packages. For example: 7-10-7. Those numbers represent the percentage by weight of each macronutrient. Higher numbers do not mean better fertilizers, only higher concentration. You should be sure to dilute higher concentrations.

Most houseplants do well with a 10-10-10 or even 5-5-5 balanced ratio. It is important to learn about your plant’s specific needs, though. For example, plants with large foliage might prefer a higher nitrogen concentration. On the other hand, plants with lots of blooming flowers and fruits would benefit from more phosphorus. Potassium promotes strong, healthy root growth, so it’s usually the same as the other numbers.

Should I Use Organic or Synthetic?

Most recommend organic. One of the few advantages of synthetic fertilizers is that they act quickly, but the tradeoff is toxic buildups. Synthetic fertilizers also tend to be concentrated and remember, over-fertilizing will kill houseplants.

On the other hand, organic fertilizers have other micronutrients such as copper and zinc and beneficial fungi and bacteria that improve the soil. They are also less likely to burn roots or cause toxic buildups in the soil.


Is organic better than synthetic?

It really comes down to preference. Organic is all-natural and environmentally friendly, making it safe and chemical-free. On the other hand, synthetic fertilizers can be more cost-effective because they are more formulated.

Do low-light plants need fertilizer?

It is not always necessary, but always make sure to read the specific fertilizing needs of your houseplants.

What is the best N-P-K ratio?

It depends. A balanced ratio is a safe bet but always research or ask about the specific needs of the plant you are fertilizing.

What are the signs that a plant needs to be fertilized?

Firstly, lack of growth in the summer. Secondly, rapid yellowing might be a sign of a lack of nutrients.

That being said, always err on the side of caution. Lighting and watering could easily be the culprits, and it’s best to resort to fertilizing as a last step to avoid over-fertilizing.

What Should I Do If I Over Fertilize?

Signs of over-fertilization include a white layer of salt buildup on the topsoil, leaf yellowing or browning, stunted growth, and defoliation, usually after the yellowing and browning.

Remove the damaged foliage. Scoop the salt buildup. Remove any granular fertilizer. Repot with fresher soil, although this could cause a lot of stress for the plant.

Leach the plant by watering it as much as possible without drowning the plant. You can place it in a tub or sink and flush out the excess nutrients. Careful with this method as the drawbacks are potential root rotting and natural ecosystem disruptions if excess chemicals find their way to waterways.

Should I buy my plant at a nursery?

You don’t have to. Nowadays, there are informative websites that support you along the way, and you can have plants shipped to your door! That includes wholesale plants!

Do clay plants need fertilizers?

Clay soil doesn’t need fertilizing as regularly because clay traps water and nutrients. The best fertilizer for clay plants is organic materials like compost and manure.