Your peace lily will need nutrients to continually draw from between fertilizing. Potting soil will ideally be some sort of blend of the ingredients you will use to make your own. Avoid using too much of this ingredient, however, since some potting soils can be dense and too heavy for peace lilies. It should comprise about 20% of your soil mix.

You can use a liquid fertilizer or a solid, granular fertilizer designed for flowering tropical and houseplants. Many houseplant fertilizers are characterized by their nitrogen, phosphorus, and potassium balance. A peace lily should have a fertilizer comprised of 20% of each of these ingredients, commonly called a 20-20-20 fertilizer. Be sure to follow the instructions on the bottle about dilution, and only use about 5% if you're incorporating a granular fertilizer; however, houseplant fertilizers are usually in liquid form and should be mixed with distilled water.

Compost is a great addition to your soil, as it will continue to enrich the mixture as the matter decays. If you're using your own organic matter, make sure it's considerably decayed. If it has manure, especially, make sure the matter is two to four months-decayed, or it may burn the roots. Organic matter can also be purchased online or from larger home improvement retailers ready-to-use. Organic matter and compost should compose about 10% of your soil mix.

Worm castings are essentially worm poop, which is another crucial type of fertilizer. Worm castings also have the added benefit of repelling pests like mites and aphids. Since peace lilies are susceptible to spider mites, adding worm castings throughout your soil and at the top as you finish potting can protect your plant. This ingredient should make up about 5% of your mix; you only need a handful for a small pot.

Coconut coir is made from the husk of coconuts and can be found in fibrous and ground forms. It's good at retaining water, which will be crucial to keep the soil from drying out too much between waterings. Loose soil also struggles to retain nutrients, so this is an important ingredient. It should comprise about 20% of your soil mix.

If you don't have coconut coir at your disposal, you can use its more popular and widely used alternative: peat moss. This relatively inexpensive option also retains water, which is crucial when trying to balance airiness and the ability to hold moisture in tropical plants. Peat moss is made from the dead fibrous materials of a number of mosses. Some gardeners prefer to avoid the ingredient because of the detrimental environmental effects of removing it from bogs for commercial and personal use.

As a sort of antidote to the water-retaining capabilities of peat moss or coconut coir, perlite is a natural volcanic rock. It can be used to aerate the soil and should make up about 15% of your soil mix. You can increase this amount depending on what your plant likes and how loose the soil is after you've completed the entire process.

If you don't have access to perlite, you can also use horticultural charcoal to aerate your soil mix. Horticultural charcoal is usually in the form of chips and is porous enough to have a similar effect to perlite. It's also absorbent, which is good to have if you have the tendency to overwater your plants. Additionally, charcoal helps capture odors within the soil.

Orchid bark is a slightly more niche ingredient, but its benefits are well worth the effort of finding it online or in a store. It is also used to loosen soil and improve drainage, usually in orchids but also in houseplants like monstera deliciosas. This ingredient should make up about 10% of your potting mix.