What is the Purpose of Perlite in Potting Soil? [7 Benefits]

Perlite is a natural soil additive that improves soil drainage, reduces soil compaction, and helps your soil hold the ideal amount of water for many species of potted plants. Perlite is especially good to add to your soil if you are growing cactus or succulents. It also helps plant cuttings take root in new soil. Perlite provides all these benefits without altering the soil pH or introducing any synthetic chemicals.

What is the purpose of perlite in potting soil?

What is Perlite?

Perlite is actually a form of rock. This lightweight material is made by heating volcanic glass until it pops like popcorn, expanding up to 16 times its original size. The resulting “popped” perlite kernel is a white, porous material that holds air and water within the soil to encourage plant health.

  • Perlite is a type of volcanic rock.
  • Gardening perlite is made by heating mineral perlite until it “pops” like popcorn.
  • Perlite is not made of plastic or styrofoam.

Perlite is typically mixed into potting soils or compost to help plants perform better. It is not a type of soil, nor is it plastic or styrofoam, as some believe. It is a naturally occurring mineral that has been exposed to high temperatures.

What are the Top 7 Benefits of Perlite in Soil?

If you’ve bought a commercial potting mix or a potted plant you’ve probably encountered the little white pebbles known as perlite. You may be wondering why it’s used. You may also be wondering if it would be good to mix perlite into your garden soil. Here are the top benefits of perlite:

Brings Water to Plant Roots

Perlite’s surface is porous, which allows particles of perlite to retain small amounts of water. Mixing perlite into compost, potting soil, or garden topsoil helps to evenly distribute moisture throughout the soil. This allows roots to access water as needed without requiring you to overwater your plants.

Improves Drainage

Unlike other water-retaining elements that may make the ground boggy, perlite encourages drainage. The lightweight, porous soil amendment allows water to percolate through the soil and allows excess water to drain away. This prevents standing water, root rot, and other negative affects your plants may suffer due to too much water.

Prevents Soil Compaction

The presence of perlite in the soil stops soil from becoming hard and compact. This is ideal because semi-loose soil with perlite allows plants to develop strong, deep roots. Overly compact soil without perlite hinders root growth. The air trapped in porous perlite helps naturally aerate the soil with very little effort on your part.

Encourages Low-Water Plants to Thrive

Perlite is an ideal soil additive if you are growing succulents, cacti, or other plant varieties that do best with relatively low amounts of water. The presence of perlite in the soil mix helps excess water drain away. This provides arid-region plants with just the right amount of water to thrive. Soil without perlite can hold too much water. Large amounts of water retention in potted plants result in diseased roots and struggling plants.

Helps Cuttings Take Root

Have you ever wondered how some gardeners turn root and branch cuttings into whole new plants? Perlite is often the answer. A 50/50 perlite-and-soil mix, or even 100% perlite planting techniques, provide the perfect environment for cuttings to grow roots. Once these plants establish themselves, they’re ready for transplanting.

Preserves Soil Ph

Perlite is not an acidic or base substance, meaning it won’t change soil chemistry. Other soil amendment products designed to aid water retention—such as peat moss—can make soil more acidic. Soil with an extremely high or low pH prevents plants from pulling nutrients from the soil. This leads to dead or dying plants. Perlite provides several benefits without the drawback of ruining your soil quality.

It’s a Natural Choice

Perlite is not a synthetic material and contains no chemicals, styrofoam, or plastics. Those little white pieces in your potting soil are an organic material. Perlite is a completely natural product. You can follow 100% organic gardening practices and use perlite to boost the performance of potting soil, compost, or garden soil.

How Much Perlite Should You Add to Potting Soil?

If you are making your own perlite-and-soil mix, use a 1:4 ratio of perlite to soil or compost. This ratio is similar to what you will find in most potting soils at your garden center. It allows for excellent drainage but still contains enough soil to provide your plants with nutrients.

  • Add 1 part perlite for every 4 parts compost or soil in potting soil.
  • This ratio provides ideal drainage for most dry soil.
  • Moisten perlite prior to mixing with soil to remove dust.

If you are using perlite in your own homemade potting soil, it’s a good idea to moisten the perlite with water before using it. This removes the dust from the perlite, making it far more effective when mixed with your soil.

Does Perlite Add Nutrients to Soil?

Perlite is not a fertilizer. It doesn’t add significant nutrients to the soil, nor does it introduce healthy soil microbes. Horticultural perlite is best used to provide proper drainage and aeration to potting mix, but do not rely on it for soil nutrients.

  • Perlite does not add nutrients to the soil.
  • All the nutrients your plants will gather via root must come from the compost and soil mixed with the perlite.
  • Fertilize plants to replenish nutrient levels in the soil.

To feed your plants, make sure you mix perlite with soil that contains high levels of organic material. One way to add organic material is by mixing in compost. It’s also essential to periodically provide fertilizer to potted plants. The soil needs to be replenished with nutrients to keep your plants healthy and strong.

Should You Add Perlite to Potting Soil?

Perlite is an incredible soil additive useful for potted plants, container gardens, and in-ground gardens. The benefits of adding perlite to your soil are:

  • Improves healthy water retention levels in soil.
  • Encourages proper soil drainage.
  • Helps soil resist compaction.
  • Provides the ideal environment for potted plants such as succulents and cacti.
  • Boosts the survivability of plant cuttings.
  • Won’t throw off soil pH.
  • Is 100% natural.

Whether you are working with clay soils that need extra drainage or you want to plant succulents in the right soil so they’ll thrive, perlite is an incredible answer. These little white specks can provide a world of good to your garden, indoors or out.

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