The 7 Best Homemade Liquid Fertilizer for Indoor Plants

Fertilizers are needed to keep our indoor plants healthy. But not all fertilizers are made equal. In fact, synthetic products can be potentially harmful to our beloved plants.

This is why I make my own homemade liquid fertilizer for indoor plants. There are quite a few options at your disposal, with most found in your kitchen cupboard. Let’s jump in…

The Best Homemade Liquid Fertilizers for Indoor Plants

  1. Worm Tea

Using worm farms is a great way to get rid of your kitchen scraps and feed your plant at the same time. This is one of the most economical ways to fertilize indoor plants.

Simply drop any leftovers into the worm farm, and then give the worms some time to break the food down into a nutritious fertilizer mix.

If the thought of worms in your kitchen puts you off, you can always use a compost bin instead. The Bokashi product (Amazon link) breaks down your leftovers into a nutritious liquid fertilizer that can be poured on your indoor plants.

  1. Cooking Water

Are you someone who regularly boils or steams vegetables? If so, you can use the excess water as natural fertilizer for indoor houseplants. This is very simple to do – just remember to let the water cool down before pouring it over your plant.

  1. Coffee

Humans love coffee, and so do our houseplants. In fact, we have a whole article on how you can use coffee grounds as fertilizer. Coffee works by adding essential nutrients, like nitrogen, to your soil.

Coffee is best used on plants that enjoy slightly acidic soil. Simply make a coffee as you normally would, let it cool down to room temperature, and then pour the coffee into the soil of your plant.

  1. Fish Tank Water

This sounds like a weird one, but you can use fish tank water as plant fertilizer. This is because fish waste contains nutrients that plants love, like potassium and nitrogen. You can simply use a cup to scoop the water from your tank, and then carefully pour the nutritious liquid into the soil.

  1. Green Tea

Just like with the coffee grounds, you can use green tea on your plants, especially if your plant enjoys a slightly more acidic soil. While some pour their green tea straight onto the plant, others rip a used tea bag open and mix it with the plant’s soil.

  1. Epsom Salt Water

There’s a massive trend to put Epsom salts in our bath water. It makes a lot of sense as Epsom salts contain magnesium and sulphate. These compounds are great for our skin, but also allow our plants to thrive to their maximum potential.

You can make a liquid Epsom salts plant fertilizer by mixing a teaspoon of salt with a litre of water. You can then water each houseplant like you usually would.

  1. Molasses

Those who enjoy cooking will likely have a jar of molasses in their cupboard. If you’re not aware of what molasses is, it’s a thick liquid made from sugar cane. Dark in colour and full of nutrients, molasses is one of the best natural liquid fertilizers for houseplants.

Just like with the salts, you should mix a tea spoon with a litre of water, and then water your plants like you usually would.

Why Do Indoor Plants Need Fertilizer?

The reason fertilizers work is because indoor plants need a range of nutrients to thrive. Stuff like nitrogen, potassium, calcium, and magnesium.

These natural houseplant fertilizers break down over days and weeks, which slowly feed our houseplants with the essential nutrients they need to grow and look their best.

When Should Indoor Plants Be Fertilized?

Plants require the most fertilizer during the spring and summer months when they are at maximum growing capacity. Essentially, you should give your plant more nutrients when the plant does more of its growth.