Soil - Mushrooms, Fuzz, & Nutrients

[Alyssa Piombo]

By Maddy Hogan

We’ve harped on the importance of light and watering when it comes to indoor plants and now we are ready to close the loop by discussing all things indoor potting soil. Arguably one of the most important factors in an indoor plant's health, the soil is where plants obtain their nutrients, water, and support. Let’s dive into indoor plant soil, soil nutrients, and additives that will allow your indoor plants to thrive.

Soil Nutrients

Just like humans need water and nutrients to survive, our indoor plants need nutrients to grow and remain healthy. Of all the nutrients required, the most important macronutrients are nitrogen (N), phosphorus (P), and potassium (K), which is often referenced as NPK percentages on soils or plant food nutrients. Nitrogen helps the plants produce chlorophyll that gives plants their green coloration and is essential for indoor plants to turn sunlight into energy via photosynthesis. Phosphorus assists in the development of a plants roots, flowers, and in some instances fruits, while potassium is required for overall plant health and the battling of disease and pests. While macronutrients are the most important, indoor plants also need secondary macronutrients and micronutrients to assist in important cell function, chlorophyll production during photosynthesis, and long-term disease resistance.

When choosing your indoor potting soil, it is important to take these macro and micronutrients into consideration. Indoor potting mixes, like those from The Good Dirt and Black Gold that we use at Riza, are typically a mix of peat moss, perlite, or vermiculite in addition to soil, bark, and any gritty rock-like texture. This blend of substances in indoor potting mixes supports a nutrient balance, while allowing indoor plants to retain water while also draining appropriately.

Mushrooms & Fuzz

With nutrient-dense soil, especially during the shift from cool winter to warmer spring months, the appearance of mushrooms or fuzz may occur on your indoor potting soil. The conditions for mushrooms or fuzz to appear on your indoor potting soil usually means that your soil is too damp or soggy. The mushrooms and fuzz themselves are typically not harmful to your indoor houseplants, but indicate that a consistently soggy soil could be an issue. It is important to allow your plants to dry out for longer periods of time during cooler months and by limiting the prolonged moisture levels in the soil, you will limit the presence of mushrooms or fuzz growing in your indoor potted plants.

Mushrooms are a representation of a fruiting body of fungi that lives in a nutrient-rich soil. These fungi feed on organic matter within the soil that is decaying, such as fallen leaves or roots. This increases in a moist environment or when your indoor potting soil retains moisture for longer periods of time, allowing the decay process to accelerate and mushrooms to appear. Fuzz in your indoor soil is a display that your soil contains beneficial fungi that help break down organic matter in the soil, providing a symbiotic relationship with the roots and overall health of your indoor plants.

Soil Additives

In addition to choosing a nutrient-dense potting soil for your indoor plants, there are also several additive substances that we want to educate you about. These substances can be beneficial on a case by case basis and are dependent on other factors such as the type of plant, what zone you reside in, and what indoor lighting your plant will have in its space.

Perlite is a mineral created from a volcanic matter that is exposed to heat until it expands and becomes porous. This helps with improving soil drainage and compaction, which can limit root growth and nutrient absorption. We carry perlite available for purchase at Riza in our Downtown Napa location.

Peat Moss is an organic matter that improves water retention within indoor potting soil. Peat moss is a helpful addition to plants that require a consistently moist, but not soggy soil. We carry perlite available for purchase at Riza in our Downtown Napa location.​

Fish emulsion is rich in nitrogen, phosphorus, and potassium to provide a nutrient boost to indoor potting soil in between re-potting. We have some at Riza in the SALE bin in the back!​

It is important to read soil nutrient and additive instructions carefully, or speak to a knowledgeable team member at the Riza store, because over-fertilization can occur which can damage the roots or leaves (and future leaves) of your plant as a result of nutrient burn. The same goes for general fertilization with watering, we recommend fertilizing your plants once per month during the active growing season of April - October.

Riza has a Soil Bar in our Downtown Napa location at 1300 1st Street, Suite 355 in Napa, where we can re-pot all your indoor plants this spring and get them prepared for the active growing months this summer. All the additives and nutrients mentioned in this post can be found at our Soil Bar or in the fertilizers we carry. Give us a call or swing by in-person to chat about what your indoor plants need, we are happy to help you all have a thriving indoor plant scene!