The Silent Saviour: Why Drainage is Non-Negotiable for Happy Succulents and Cacti

In the captivating world of succulents and cacti, with their architectural forms and resilient reputations, it's easy to focus on sunlight and the occasional sip of water. However, there's a less glamorous but absolutely crucial element that often gets overlooked: drainage. Think of it as the unsung hero, the silent Saviour that stands between your beloved desert dwellers and a soggy demise.

​Preventing Root Rot: This is the big one. When soil stays consistently wet, the air spaces within it are filled with water, depriving the roots of the oxygen they need to respire. This creates an anaerobic environment that encourages the growth of harmful fungal pathogens, leading to the dreaded root rot. Once root rot sets in, it can be difficult to reverse, and often the plant will succumb.​​

Avoiding Water Retention Issues: Many potting mixes designed for general houseplants are too dense and retain excessive moisture. While this is beneficial for water-loving plants, it's a death sentence for succulents and cacti. This constant dampness can also lead to other issues like edema (water blisters on leaves) and fungal diseases.

Encouraging Healthy Root Growth: When the soil drains well, the roots are encouraged to actively seek out moisture, leading to a stronger and more extensive root system. This makes the plant more resilient to drought and nutrient uptake more efficient.

Proper drainage is absolutely crucial for healthy potted plants, as stagnant water can lead to root rot and other issues. Here's a breakdown of the best ways to add or improve drainage to a pot:

What does good drainage look like?

1. Drainage Holes are King:

•  Always prioritize pots with drainage holes. This is the most effective and straightforward way to ensure excess water can escape.

• If your pot doesn't have drainage holes, consider drilling them. Use a masonry drill bit for ceramic or terracotta pots, going slowly and keeping the drill bit wet to prevent cracking. For plastic pots, a regular drill bit will work.

• Cover drainage holes (optional but recommended): To prevent soil from washing out, you can cover the drainage holes with:

  • Broken pieces of terracotta pots or crockery

  • Mesh screen

  • Coffee filters

  • Landscape fabric

2. Amend Your Potting Mix:

The right potting mix is essential for good drainage. Even if your pot has holes, a dense, heavy soil can still lead to waterlogging.

• Use a well-draining potting mix: Look for mixes that contain ingredients like:

• Perlite: Lightweight volcanic glass that creates air pockets and improves aeration.

• Vermiculite: A porous material that helps with water retention while also improving drainage.

• Coarse sand: Adds grit and prevents compaction.

• Coco coir: An environmentally friendly option made from coconut husks that improves porosity.

• Orchid bark: Good for plants that need excellent aeration, like orchids (of course!) and some aroids.

• Add amendments to your existing soil: If your current potting mix is too dense, you can mix in extra perlite, coarse sand, or coco coir to improve its drainage capabilities.

• Compost: Incorporating compost can also improve soil structure and aeration over time.

3. "Staging" or Double Potting:

This is a fantastic method for decorative pots without drainage holes.

•  Keep the plant in its nursery pot: The plastic nursery pot usually has multiple drainage holes.

• Place the nursery pot inside the decorative pot: When watering, you can simply lift the nursery pot out, water it thoroughly in a sink or outdoors until water drains, and then place it back in the decorative pot once it has stopped dripping. This prevents water from accumulating in the bottom of the decorative pot.

4. The "False Bottom" or Drainage Layer (Use with Caution):

Historically, people would add a layer of rocks, gravel, or broken pottery at the bottom of a pot to improve drainage. While this seems intuitive, it's generally not recommended for improving drainage within the soil.

•  Why it's often a myth: Water tends to accumulate at the interface between the potting mix and the drainage layer (this is called a "perched water table"). The soil will only drain into the gravel once it's completely saturated above that layer, meaning the roots are still sitting in water for longer than ideal.

• When it might be useful:

• Adding weight: If you have a very large, lightweight pot that's prone to tipping over in windy conditions, a layer of heavy rocks at the bottom can add stability.

• Reducing soil volume: In extremely large planters, you can fill the bottom with lightweight, non-biodegradable materials like empty plastic bottles (with caps on to prevent water collection), crushed cans, or packing peanuts, then cover them with landscape fabric before adding soil. This reduces the amount of potting mix needed, making the pot lighter and more cost-effective to fill. However, it's not primarily for drainage.

Key Takeaways for Optimal Drainage:

•   Drainage holes are non-negotiable for most plants.

• A well-draining potting mix is your best friend.

• Consider double potting for aesthetic pots without holes.

• Avoid using rocks or gravel as a "drainage layer" at the bottom of the pot, as it can actually worsen drainage issues.

• Empty saucers regularly: If your pot has a saucer, don't let it sit in standing water.

In conclusion, while the allure of a perfectly plump succulent or a stoic cactus might lie in its form, remember that the foundation of their health lies beneath the soil. Prioritizing excellent drainage is not just a suggestion; it's a fundamental requirement for their survival and thriving. Give your succulents and cacti the gift of well-draining conditions, and they'll reward you with their unique beauty for years to come.

By following these tips, you'll create an environment where your potted plants can thrive!

What about glass terrariums?

Given that a glass bowl lacks drainage holes, we have to manage moisture very carefully to prevent root rot. Here's the best way to pot a succulent terrarium in a glass bowl, minimizing drainage issues:

The Key is to Manage Moisture, Not Rely on Drainage (as there are no holes):

•  Choose the Right Container and Succulents:

  • Wide-mouthed glass bowl: A wider opening allows for better airflow, which helps with evaporation and prevents humidity buildup, crucial for succulents. Avoid narrow-necked containers.

  • Drought-tolerant succulents: Select succulents that are highly tolerant of infrequent watering and prefer drier conditions. Examples include:

  Haworthia species, Gasteria species, Sempervivum (Hens and Chicks), some Crassula species (e.g., 'Jade Plant' if you are extremely careful), Small Echeveria varieties (though they generally prefer more airflow than a terrarium provides).

• Avoid highly sensitive succulents or those that need more consistent watering.

• Activated Charcoal Layer (Optional but Recommended):

  • Purpose: While it doesn't provide drainage, activated charcoal can help absorb odors and filter impurities from the water that does accumulate, keeping the environment cleaner. It's not a substitute for drainage, but it can help manage stagnant conditions.

  • How much: A thin layer, about 1/2 to 1 inch (1-2.5 cm) at the bottom.

• Use a SUPER Well-Draining Potting Mix:

  • This is the most critical component for success. Since excess water can't drain out, the mix itself must dry out quickly.

  • Ingredients: Use a specialized succulent/cactus mix. Even better, amend it heavily yourself:

     * 50% succulent/cactus potting mix

     * 25% perlite

     * 25% coarse sand or pumice

   * This gritty mix will allow water to pass through quickly and minimize the amount of water retained, thus preventing the roots from sitting in soggy conditions.

• Careful Planting:

  • Place a layer of your super well-draining mix over the charcoal (if used).

  • Gently remove your succulents from their nursery pots, shaking off as much old soil as possible. This helps to reduce any moisture-retentive soil from their previous environment.

  • Arrange your succulents in the bowl, ensuring they have enough space for airflow around them. Avoid overcrowding.

  • Backfill with your specialized potting mix, ensuring the base of the plants is covered, but avoid burying the leaves.

  • Top Dressing (Optional but Beneficial):

  • A layer of small gravel, sand, or decorative stones on top of the soil can help reduce evaporation slightly (which might seem counter-intuitive, but it helps keep the very top layer dry to prevent fungal issues) and adds to the aesthetic.

• MOST IMPORTANT: EXTREMELY CAREFUL WATERING:

  •    This is where success or failure lies. With no drainage holes, every drop of water stays in the bowl.

  • Water sparingly: Water much less frequently than you would a potted succulent with drainage. Err on the side of underwatering.

  • Method: Use a watering can with a thin spout or even a squeeze bottle to precisely deliver small amounts of water directly to the base of each plant, avoiding the leaves and the glass sides as much as possible.

• Check the soil: Before watering, stick your finger deep into the soil. Only water when the soil is completely dry for several days (or even weeks, depending on your environment).

  
  

• Observe: Watch your plants closely for signs of thirst (slight wrinkling of leaves) before watering. Never water on a schedule.

• Evaporation: The only way water leaves the system is through evaporation or plant transpiration. A wider opening helps with this.

  
  

•  Airflow and Light:

  •    Good Airflow: Place the terrarium in a spot with good air circulation. This helps with evaporation.

• Bright, Indirect Light: Succulents need bright light, but direct, intense sun through glass can magnify heat and humidity, which is detrimental. Bright, indirect light is best.

Why the "Drainage Layer" of Rocks is a Bad Idea (Revisited):

As discussed, adding a layer of rocks at the bottom of a pot without drainage holes doesn't create drainage. Instead, it creates a "perched water table" where water accumulates above the rock layer, saturating the soil and the plant roots. In a sealed terrarium, this water has nowhere to go, leading to stagnant, oxygen-depleted conditions perfect for root rot and fungal growth. The aim in a terrarium is to manage moisture levels in the soil, not to facilitate water flow through the system.

In summary, while challenging, a successful succulent terrarium in a glass bowl relies entirely on meticulous moisture control and a highly porous potting mix, compensating for the lack of actual drainage.