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For many gardeners, the temptation strikes every spring – why spend money on potting soil when there’s free topsoil ready for the taking in your own backyard? Scooping up that rich, familiar dirt to fill your containers seems like a no-brainer.

Yet what works wonders in your garden beds doesn’t always translate into container success. Before digging up topsoil for your pots and planters, discover why it tends to fall short for container plants.

In this article, you’ll learn:

  • The key differences between topsoil and potting mixes
  • What critical amendments can transform topsoil into usable container soil
  • Which plants won’t mind amended topsoil, and which demand potting mix
  • Troubleshooting issues like drainage, nutrients, and pests in topsoil containers

With the right information and techniques, gardeners can occasionally repurpose topsoil for containers under the right conditions. But more often than not, quality potting soil is a wise investment for thriving, hassle-free container gardens.

Is top soil the same thing as potting soil?

No, topsoil and potting soil are not the same. Topsoil refers to the upper layer of native soil found in yards and gardens. It is naturally occurring, heavy, and dense. Potting soil is a specially formulated, lightweight mix designed for container gardening.

Topsoil Vs Potting Mixes: Key Differences

Topsoil is the upper, outermost layer of soil found in yards and gardens. It is composed of naturally occurring organic materials like decaying leaves, insects, fungi, bacteria, as well as sand, silt, and clay particles. Topsoil is dug up from the earth prior to installing lawns, garden beds, or landscaping elements.

In contrast, potting soil is an artificial soil mix specially created for growing plants in containers. High quality potting mixes are designed to be loose, well-draining, and lightweight. Typical ingredients include:

  • Peat moss or coconut coir to retain moisture
  • Perlite or vermiculite to improve drainage and aeration
  • Compost, worm castings, or other organic matter for nutrients
  • Sand or bark chips to create loose texture

Additionally, potting soils are pH adjusted, fertilized, and sterilized to optimize conditions for container plants. They are soilless mixes blended for the specific needs of potted plants.

Topsoil is heavy, dense, and can easily become compacted in containers. Potting soil is formulated to be porous and fast-draining for excellent root growth. While topsoil provides in-situ nutrients, only high quality potting mixes offer the proper balance for thriving container plants.

Top Soil Vs Garden Soil

Topsoil and garden soil are distinctly different types of earth used in gardening and landscaping. Topsoil refers to the uppermost layer of native soil found on the ground’s surface. It is composed of mineral particles like sand, silt and clay, along with some organic matter from decomposed plants, leaves, and animals.

Topsoil exists naturally in yards and landscapes without any intentional enhancement. In contrast, garden soil is soil that has been modified intentionally to optimize it for actively growing plants. Gardeners often amend native topsoil and subsoils by mixing in organic matter like compost or manure to improve texture, fertility, and drainage.

Garden soil is also treated to adjust pH, eliminate weeds/pests, and incorporate balanced fertilizers and nutrients that plants need to thrive. While topsoil occurs naturally, garden soil is an engineered growing medium carefully cultivated to provide ideal conditions for all types of plants, flowers, vegetables, and other gardening purposes. The two soils have very different properties in terms of texture, structure, drainage, nutrients, and suitability for plant growth.

If you are wondering what the difference is between garden soil and potting mix, check out that guide as well to decide if you should be using it in your containers.

Pros of Using Topsoil for Containers

Affordable and Accessible
Topsoil is extremely affordable and readily available, making it tempting for container gardening. Rather than purchasing bags of potting mix, gardeners can simply dig up existing topsoil from their yard or surrounding areas at little to no cost.

Contains Some Nutrients
Since topsoil originates from the earth, it will contain some naturally present organic matter and minerals that provide basic nutrients for plants. The organic content includes partially decomposed leaves, twigs, and other debris that releases nutrients as it breaks down further.

May Work for Temporary Plants
Topsoil could potentially be used short term for hardier annual plants or temporary transplants that will be moved to the ground later on. Certain resilient flowers and vegetables may be able to tolerate unmodified topsoil for a season.

Gets Better With Amendments
While untreated topsoil is not ideal, amending it properly with compost, fertilizer, and other additions can get it closer to usable potting soil. With some effort, topsoil can be transformed into a viable container mix.

Cons to using topsoil for container gardening

Poor Drainage
One major downside of topsoil is that it typically retains too much moisture and does not drain well in containers and pots. This can lead to root rot and other problems in wet, dense topsoil.

Compaction
Topsoil tends to compact and settle over time in pots and planters. This reduces the oxygen content in the soil and stunts root growth. Plants become stressed and undersized.

Nutrient Deficiencies
While topsoil contains some organic matter, the levels of essential nutrients like nitrogen, phosphorus and potassium are often not high enough for vigorous container plant growth.

Diseases & Pests
Using straight topsoil introduces risks of fungal diseases, bacteria, nematodes, insects and weed seeds. Contaminants can quickly spread to container plants.

Incorrect pH
Topsoil may have an incompatible pH for the plants you wish to grow. It could be too acidic or alkaline without amendments to reach optimal container plant pH.

Weeds
Viable weed seeds in untreated topsoil will germinate rapidly and compete with container plants for water, light and nutrients.

Heavy to Move
Dense, heavy topsoil is difficult to transport and work with compared to lightweight potting mixes formulated for containers.

Making Topsoil Work as Potting Soil

Plain topsoil is rarely suitable for containers as-is. However, with some effort it is possible to amend and condition topsoil into a usable potting mix.

First, mix in organic materials like compost, peat moss, or coconut coir. Aim for around 30% organic content. This lightens dense topsoil and improves moisture retention.

Next, add perlite or vermiculite, about 20% by volume. These porous rocks will significantly increase drainage and aeration when blended into topsoil.

Test and adjust the pH of the amended topsoil to fall between 6.0-6.5, ideal for most container plants. This prevents nutrient deficiencies.

Finally, mix in a balanced organic fertilizer according to package instructions before potting up containers. This will provide plants with necessary nutrition.

How Do You Turn Topsoil Into Potting Soil?

  • For organic matter, add 3-5 cups of compost or peat moss per gallon of topsoil. Worm castings and rotted manure also work well.
  • Mix in 1-2 cups of perlite or vermiculite per gallon of topsoil to improve drainage. Coarse perlite works best to create air pockets.
  • Supplement with 1-2 cups of coconut coir, shredded bark or pine needles per gallon topsoil to retain moisture.
  • Test pH after amending. Topsoil is often too acidic. Add lime if below 6.0 or sulfur if above 6.5 to reach optimal pH for containers.
  • Choose a balanced organic fertilizer with an NPK ratio like 5-5-5 or 8-2-4 and mix according to label instructions. Start with 1-2 tablespoons per gallon of soil.
  • Consider sterilizing amended topsoil by baking in the oven at 180°F for 30 minutes to kill any weed seeds or pathogens.
  • Plan to re-test and amend container topsoil yearly, as nutrients deplete over time. Top-dress containers with compost or fertilizer as needed.

With the right ratio of additions, even dense garden topsoil can be transformed into a nutritious, fast-draining potting mix suitable for containers.

Can You Grow Plants in Just Topsoil?

Growing plants directly in plain, untreated topsoil is generally not recommended for containers and pots. Topsoil dug straight from the ground usually does not provide ideal conditions for most container plants.

While amending and conditioning topsoil for containers takes effort, there are some situations where it could provide adequate results:

For temporary use with annuals – Fast-growing resilient annual flowers and vegetables that will be harvested within a season may tolerate amended topsoil long enough to survive one growing cycle. Fast-growing annuals that only need to survive one season, like marigolds, zinnias, and tomatoes, may grow acceptably in amended topsoil for a short period. However, check the soil frequently for moisture, nutrients, and compaction issues.

Avoid topsoil for long term containers or sensitive plants – Permanent containers, shrubs, trees, and delicate plants like orchids or herbs are not good candidates for topsoil. They require the better drainage and fertility that commercial potting mixes provide.

Small or experimental container plantings – Amended topsoil may suffice for very small pots or experimental propagations that are not expected to thrive long term.

With frequent fertilizing and close monitoring – In amended topsoil, container plants will likely need more frequent watering, fertilizer doses, and attentive care to ensure they are not stressed.

For hardy, less-demanding plants – Tough, drought-resistant perennials like lavender, rosemary, sedums, yuccas may grow acceptably in properly conditioned topsoil for a season or two.

When potting soil is unavailable or cost-prohibitive – In situations where purchasing or obtaining potting mixes is difficult, amended topsoil could be used out of necessity as a low-cost option.

Never use topsoil from an unknown source or location. Only use topsoil from your own yard where you know the history. Topsoil acquired from elsewhere could contain contaminated runoff, weed seeds, or diseases that can devastate container plants before it is noticed.`

With close attention and care, some plants may grow reasonably well short term in amended topsoil. But it still falls short of quality potting mixes designed for optimal drainage and nutrients in containers.

Troubleshooting Topsoil Container Problems

Poor drainage/waterlogging

  • Mix in more perlite, vermiculite or bark to improve drainage
  • Create drainage holes if lacking and clear any clogged holes
  • Use containers with adequate drainage and no saucers

Nutrient deficiencies

  • Test soil and adjust pH to 6.0-6.5 if too high/low
  • Mix in balanced fertilizer per label instructions
  • Top dress containers with compost/manure every 2-3 months

Pest issues

  • Sterilize reused topsoil prior to potting by baking or solarizing
  • Remove and destroy affected plants immediately
  • Treat insects with neem oil or insecticidal soap
  • Prevent disease spread by spacing and air circulation

Compaction/settling

  • Loosen and cultivate topsoil monthly with a trowel or fork
  • Top dress containers with compost to add air pockets
  • Repot plants in fresh topsoil as needed

Monitoring soil moisture, nutrients, and pests closely can help avoid and correct issues with topsoil in containers. Address problems immediately before they worsen.

Is Top Soil Good For Potted Plants? Final Thoughts

While plain topsoil is not well-suited for containers, it is possible to transform it into usable potting soil with the right amendments and effort. Adding organic matter, drainage materials, pH adjusters, and fertilizer can potentially create an adequate potting mix from humble topsoil. However, even amended topsoil tends to compact and degrade more over time than commercial mixes designed specifically for container gardening.

For best results with the least hassle, purchasing a quality potting soil is worth the modest investment. Potting mixes are carefully crafted to provide an optimal blend of drainage, moisture retention, and nutrients that containers plants need to thrive. While periodic fertilizing and close monitoring can help topsoil work in a pinch, potting soil gives consistently better outcomes.

Unless other options are unavailable, turn to trusted potting soil blends over topsoil for healthier, faster growing container gardens. Or limit topsoil to temporary annuals and experimental pots. With knowledge of its drawbacks and the right amendments, gardeners can occasionally repurpose topsoil for containers under the right conditions. But potting soil is easier, more effective, and well worth the purchase.

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