The Many Lava Rock Types For Your Garden

The Many Lava Rock Types For Your Garden

When it comes to popular gardening materials, volcanic rock is up there with the best. Whether you’re using it as a landscaping supply or placing it into the soil of a potted plant for drainage, there are lots of benefits of lava rock, no matter its color.

What’s the difference between black and red lava rock? The color of volcanic rock is determined by its cooling process and mineral content, so it differs with each color.

Generally, though, there’s little difference between black and red lava rock when using them in the garden.

If you’ve been looking for a new mulching material or something to help your potted plants, lava rock is the way to go.

Before you can jump in and get a wheelbarrow full of these rocks, check out this guide for the difference between black and red lava rock and which applications they can be used for.

What is Lava Rock?

What is Lava Rock?

To get back to basics, it’s best to learn about what lava rock really is and why it’s so beneficial for the garden. These rocks are classified as igneous rock and they’re scientifically known as scoria or volcanic rock, although most gardening supply stores call them lava rocks.

The lava rocks are formed when a volcano spews out molten lava which then turns solid as it cools. There are small air bubbles present in each of these solid creations that also solidify, and thus the rock is lighter and more porous than others once it hardens.

These properties make this natural material highly prized for things like mulches and soil drainage.

Black vs Red Lava Rock

Black vs Red Lava Rock

Lava rock is a popular landscaping material and gardening supply, and it comes in three main colors red, black, and gray. The color of these rocks is determined by two main factors: how the volcanic rock was cooled and what minerals are found within them.

When it comes to lava rock being used for gardening, there’s little difference between the colors. As long as you’re purchasing quality lava rock, they both offer benefits like being porous, stable, non-toxic, and versatile, so you can use them in a range of ways.

The only difference that these colors bring is what preference the gardener has, as some people prefer the subtlety of black lava rock and others like the standout hue that red lava rock has.

If it’s buried in the soil then the color won’t matter as much, but when used as a dressing or landscaping material, you’ll want to get the color just right.

The Best Uses for Lava Rock in the Garden

The Best Uses for Lava Rock in the Garden

As one of the cheaper natural materials available for gardeners, you might be wondering how you can put volcanic rock to use. Here are a few ideas that highlight just how effective lava rock can be in the garden:

  • Improve drainage: Plants that need more assistance with drainage than others will benefit from the addition of lava rock to their soil. You can place a few at the bottom of a potted plant or on top of the soil for great results.
  • Help compacted soil: Mixing through some lava rock in your potted plants or a garden bed can help break up compacted soil. This allows nutrients, water, and air to better reach the root system of the plants.
  • Topdressing: If you’re looking for something attractive to cover your potted plants with, small lava rocks are ideal. They’re cheap and attractive and come in a few different colors, so you can match them to your garden perfectly. For larger landscaping needs, big volcanic rocks can be used for pathways and garden beds.
  • Garden mulch: Because lava rock never breaks down, it’s ideal when used as mulch. You can mix these rocks with other materials to improve their lifespan and toss them through your garden or on top of garden beds to provide nutrients to the plants below and deter weeds.

Pros and Cons of Lava Rock

Pros and Cons of Lava Rock

As one of the most utilized natural materials in the garden, it makes sense to put lava rock to good use in yours.

However, it’s worth noting the pros and cons that these small rocks come with before you start scattering them around.

The Pros

  • A single bag of lava rocks is versatile enough to be used throughout your whole garden including mulch, dressing, and soil amendment.
  • You can choose either black, red, or gray lava rocks to suit whatever look you’re going for.
  • As far as natural materials go, lava rocks are affordable and easy to buy from just about anywhere, with even better savings when you buy in bulk.
  • When used as mulch or dressing, the heavier nature of lava rock means it can’t be easily washed or blown away.
  • It’s a lot lighter than other rocks thanks to the solidified air bubbles within it, so it won’t weigh down the soil.

The Cons

  • The smaller size of some lava rocks means they can easily fall out of the bottom of potted plants with drainage holes.
  • Not all lava rocks are created equally and it can be hard to find quality products that are as genuine as they claim to be.
  • When used as mulch, lava rocks won’t impart any nutrients into the soil, so they have to be added to something else for those kinds of benefits.
  • In warmer climates, you’ll need to check that the rocks aren’t heating up too much and damaging the plants they’re surrounding.

A Powerful Rock For Your Garden

The color of the lava rock in your garden won’t have much impact on it, as long as it suits your preferences and the purpose it’s being used for.

Whether black or red, this natural substance can work wonders in the garden, so consider picking up a bag today.

Related Questions

Landscaping materials like lava rocks can be hugely beneficial to the garden when used correctly. If you’re thinking about utilizing some raw materials in your garden but don’t know where to start, read on for a few FAQs that can help.

What Do You Use Pea Gravel For?

Pea gravel is a small, pea-sized type of gravel that can be used around the garden as coverage for patios, pathways, and high-traffic areas.

The use of pea gravel in the soil can assist with drainage and aeration, so it’s got plenty of benefits both above and underground in the garden.

What is Garden Pumice?

What is Garden Pumice?

Pumice is a type of volcanic rock that can be used in the garden for various horticultural applications, in hydroponics, and even as a growing medium.

The light rock is affordable and attractive, as well as being practical, so it’s a popular choice for gardeners who prefer to use natural materials.

Can You Put Wood Chips in a Vegetable Garden?

Wood chips are better suited for surrounding established plants and should be left out of smaller garden beds, including vegetable patches.

If you do wish to add wood chips to the garden, composting them first for a year will make it easier for the plants to receive nutrients from them.


About The Author

Gina Harper grew up dreaming about farms and growing her own food. She began an urban garden to feed herself and turned it into an incredible hobby. Gina is here to teach you everything from raised beds to container gardening, how to keep plants alive and well in a smoggy city, and the works. It’s time that we carve our own piece of green earth and reap what we sow—she’s here to help you with that.