Perlite Vs. Sand: The Best Way to Improve Soil Drainage

Tired of slogging in clay soil? Large clumps, soggy conditions, and dense dirt make working in poorly draining soil a chore. Perlite and sand are two horticultural materials perfect for improving drainage, but which is best for you and your garden?

Sand vs perlite to improve soil drainage.

Contents

Drainage is one of the most important aspects of plant health. Certain plants prefer different drainage levels, from free draining to soggy. Species that originate in dry climates often prefer well-drained soil, while those from wet or swampy ones usually favor soggy or slow-draining dirt

Drainage is complicated; adding perlite or sand is the first step towards creating healthy soil. Some other materials aside from perlite and sand can prevent compaction. After deciding whether perlite or sand is better for your garden, we’ll look at other ways to maintain the site for optimal plant health.

The other factor to consider is the vessel you’re growing plants with. Containers, raised beds, and in-ground beds benefit from different drainage components; each requires different amendment techniques. 

No matter your garden setup, we’ll discover methods and materials for easily improving drainage. Grab your gloves, amendments, and a shovel. It’s time to get digging!

What is Perlite?

Small, lightweight, white, porous granules with a rough texture fill a white bag, accompanied by a green shovel placed inside.
These volcanic minerals create ideal conditions for plants.

Perlite is all-natural! It’s a volcanic mineral that looks like pumice. Manufacturers break rocks into tiny particles, heat them at high temperatures, and force them to puff up into light, airy chunks. These chunks create the ideal particle for improving garden drainage—they’re porous, lightweight, and slightly absorbent

Perlite is also incredibly cheap! It’s often more affordable than other products, as a single stone can create hundreds of perlite particles for horticultural use. Potting mixes use it as a cost-effective drainage component. Some seed starting mixes also use it, though they include tiny perlite pieces smaller than a pea seed. 

What is Sand?

A gloved hand holds a small shovel filled with fine, light beige sand above a bucket brimming with smooth, evenly textured sand.
Coarse materials help create dirt that breathes well.

Sand can refer to many different materials. It most commonly refers to soil particles of a certain size. Clay, though it forms big chunks, consists of tiny particles. Silt has medium-sized particles, while sand has the biggest ones.

Bigger particles lead to better drainage—they don’t stick together well! They let water and air flow freely and don’t absorb as much moisture as silt or clay particles. Most soils have a mix of all three components. Loamy soil contains a perfect blend of all three types; it’s best for growing crops and wildflowers.

The most promising sands for improving drainage will have the words “horticultural sand” or “horticultural grit” on their labels. They consist of broken minerals that are coarse and irregular. En masse, the particles create a free-draining soil with low absorbency. Though they aren’t as free draining as horticultural sand, you may use chemical-free builders or play sand instead.

Perlite vs. Sand

Now that we know the difference between the two materials, it’s time to determine which is best for your garden. They excel in many applications, from seed starting to amending old garden beds. Sometimes, both perlite and sand are necessary for improving drainage!

Seed Starting

Seed starting trays filled with dark, loose soil, neatly arranged with evenly spaced cells ready for planting.
Choose the right mix to grow healthy seedlings.

Every vegetable garden starts with seeds! The type of mix you use can greatly affect your seedlings’ health, no matter whether you’re starting them indoors or outdoors. The best mix for growing seeds is fertile, free-draining, and absorbent

Most seed-starting mixes contain perlite or sand when you buy them. You may add extra perlite if the blend seems soggy and dense. Otherwise, plant seeds directly into the dirt. 

Sand isn’t ideal for seed-starting mixes, as it encourages nutrients and water to drain freely from the containers. A little is okay in dense blends, though perlite is the better option. Perlite facilitates drainage while trapping air and water for plant roots to access, while sand boosts drainage but doesn’t help absorption rates. 

If you’re making a blend at home, consider trying this perfect ratio from Epic Gardening founder Kevin Espiritu and the garden hermit Jacques Lyakov:

  • ⅓ pumice or perlite
  • ⅓ coco coir
  • ⅓ compost, worm castings, and Azomite

YouTube video

Potting Soil

A woman wearing a beige apron uses a shovel to prepare loose, dark brown soil in a black plastic bucket on a table surrounded by various houseplants.
Adjust your mix for the plants you’re growing.

Whether potting soil is ideal or not depends on the plants you’re growing. Species that prefer dry conditions will benefit from a well-drained mix, while others that love moisture prefer less drainage and more absorbency. Often, a mix of both sand and perlite creates the perfect blend.

Store-bought mixes usually mixes perlite, peat moss or coco coir, and organic matter like compost. Sand is a rare component, though it’s more common in cacti, succulent, and bonsai blends. 

Perlite is best for improving drainage for houseplants, vegetables, and seedlings. Sand and perlite work well for cacti, succulents, bonsai trees, and plants from dry regions. Avoid using too much perlite or sand by mixing in a little at a time until you reach the desired consistency.

Raised Beds and Containers

A male gardener wearing yellow rubber boots empties a bucket of fresh black soil onto a raised wooden bed inside a greenhouse.
Gardening above ground makes cultivation and amending easier.

Raised beds and containers are similar, as they both involve gardening in soil above the ground. This allows for easy amending, longer growing seasons, and simple cultivation. These vessels work well for growing crops, herbs, and flowering annuals.

Perlite and sand help boost drainage levels quickly in containers, though they’re less effective in large spaces like raised beds. Soil amending takes time in large spaces, so patience is key to success. It often requires other materials aside from perlite and sand, like compost, leaf mold, or worm castings

In-Ground Beds

A gardener wearing a striped sweater inspects the texture of brown, lumpy soil in a garden bed with their hands.
Organic amendments work best for amending in-ground beds.

In-ground beds are like raised beds but without elevation. They’re level with the ground and perfect for growing crops and herbs. Amending them may prove difficult, as the larger they are, the more materials they require. 

Adding sand to in-ground beds is best if you plan on growing cacti, succulents, or other sand-loving plants. They prefer growing in gritty soil and need more sand than clay or silt. If you’re growing crops, herbs, or wildflowers, you may want to avoid adding sand in favor of other organic amendments that boost drainage. 

Horticultural sand and perlite help improve drainage in the short term, though they often lose effectiveness as time passes. Clay and loam mix with the drainage particles, and large clumps form again. They work well for containers, seedlings, and small beds, but not for large spaces. 

So, what’s the solution? For raised and in-ground beds, adding compost or leaf mold is ideal. Keep reading to learn how these two amendments boost your garden’s performance. 

Other Materials to Improve Soil Drainage

Rather than immediately changing the quality of a growing medium, organic amendments like compost and leaf mold work slowly and efficiently. They boost drainage, fertility, and porosity in existing soils. Add them weeks or months before planting, and you’ll have loose, free-draining dirt perfect for your crops. 

Compost

Male hands holding fresh, finely sifted compost soil with a rich, dark texture above a larger compost pile in a garden setting.
Keep your garden happy with nutrient-packed compost applications.

Compost is the best soil amendment! It has a load of benefits like feeding plants, fueling soil microbes, and helping sensitive plant roots. But what is compost? It’s fully decomposed organic matter. Leaves, kitchen scraps, and paper products mix to create a pile. Worms, larvae, fungi, bacteria, and archaea work together to eat the rotting waste and turn it into crumbly black humus.

Compost is best for helping drainage, fertility, and porosity. Apply a two to three-inch thick layer of the stuff twice a year to keep beds happy and healthy. It works well for feeding nutrients to vegetables, fruits, and herbs.

Leaf Mold

A pile of dry, dark brown leaves breaking down in a compost heap with a rich, earthy texture.
Boost soil fertility with decomposed leaves.

Leaf mold is like compost, except it consists only of leaves! The leaves decompose into a crumbly amendment that mirrors compost in structure, fertility, and absorbency. Though compost is rich in nitrogen and carbon, leaf mold has more carbon and is better for woody trees and shrubs.

Add leaf mold as you do compost. Spread a two to three-inch thick layer around existing plants and on new beds. Gently rake it to incorporate it into the dirt, then water well. Plant directly into leaf mold after it’s sat for two to three weeks. 

Frequently Asked Questions

What is perlite or sand used for?

Perlite and sand are two common horticultural materials for increasing drainage in potting mixes. The best sand for plants is horticultural sand, though builders or play sand works in a pinch.

Can perlite replace sand?

Though perlite and sand help increase drainage, they each have specific applications where they work best. Use perlite for houseplants, container veggies, and seed starting. Use sand for cacti, succulents, and shrubs that live in dry conditions.

Can I use sand instead of perlite?

Sand increases how fast nutrients and water drain from the soil, while perlite traps air while also allowing water to flow freely. Use sand for plants that need little nutrients and water. Use perlite for other species, mixing it well with other soil components to create the perfect mix.

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